Merge tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe: "Core block changes that have been queued up for this release: - Remove dead blk-throttle and blk-wbt code (Guoqing) - Include pid in blktrace note traces (Jan) - Don't spew I/O errors on wouldblock termination (me) - Zone append addition (Johannes, Keith, Damien) - IO accounting improvements (Konstantin, Christoph) - blk-mq hardware map update improvements (Ming) - Scheduler dispatch improvement (Salman) - Inline block encryption support (Satya) - Request map fixes and improvements (Weiping) - blk-iocost tweaks (Tejun) - Fix for timeout failing with error injection (Keith) - Queue re-run fixes (Douglas) - CPU hotplug improvements (Christoph) - Queue entry/exit improvements (Christoph) - Move DMA drain handling to the few drivers that use it (Christoph) - Partition handling cleanups (Christoph)" * tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block: (127 commits) block: mark bio_wouldblock_error() bio with BIO_QUIET blk-wbt: rename __wbt_update_limits to wbt_update_limits blk-wbt: remove wbt_update_limits blk-throttle: remove tg_drain_bios blk-throttle: remove blk_throtl_drain null_blk: force complete for timeout request blk-mq: drain I/O when all CPUs in a hctx are offline blk-mq: add blk_mq_all_tag_iter blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx blk-mq: use BLK_MQ_NO_TAG in more places blk-mq: rename BLK_MQ_TAG_FAIL to BLK_MQ_NO_TAG blk-mq: move more request initialization to blk_mq_rq_ctx_init blk-mq: simplify the blk_mq_get_request calling convention blk-mq: remove the bio argument to ->prepare_request nvme: force complete cancelled requests blk-mq: blk-mq: provide forced completion method block: fix a warning when blkdev.h is included for !CONFIG_BLOCK builds block: blk-crypto-fallback: remove redundant initialization of variable err block: reduce part_stat_lock() scope block: use __this_cpu_add() instead of access by smp_processor_id() ...
2026-01-06 12:30:45 -08:00 · 2020-06-02 15:29:19 -07:00
parent 1966391fa5 abb30460bd
commit 750a02ab8d
122 changed files with 4514 additions and 1493 deletions
--- a/Documentation/block/index.rst
+++ b/Documentation/block/index.rst
@@ -14,6 +14,7 @@ Block
   cmdline-partition
   data-integrity
   deadline-iosched
+   inline-encryption
   ioprio
   kyber-iosched
   null_blk
--- a/Documentation/block/inline-encryption.rst
+++ b/Documentation/block/inline-encryption.rst
@@ -0,0 +1,263 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+Inline Encryption
+=================
+
+Background
+==========
+
+Inline encryption hardware sits logically between memory and the disk, and can
+en/decrypt data as it goes in/out of the disk. Inline encryption hardware has a
+fixed number of "keyslots" - slots into which encryption contexts (i.e. the
+encryption key, encryption algorithm, data unit size) can be programmed by the
+kernel at any time. Each request sent to the disk can be tagged with the index
+of a keyslot (and also a data unit number to act as an encryption tweak), and
+the inline encryption hardware will en/decrypt the data in the request with the
+encryption context programmed into that keyslot. This is very different from
+full disk encryption solutions like self encrypting drives/TCG OPAL/ATA
+Security standards, since with inline encryption, any block on disk could be
+encrypted with any encryption context the kernel chooses.
+
+
+Objective
+=========
+
+We want to support inline encryption (IE) in the kernel.
+To allow for testing, we also want a crypto API fallback when actual
+IE hardware is absent. We also want IE to work with layered devices
+like dm and loopback (i.e. we want to be able to use the IE hardware
+of the underlying devices if present, or else fall back to crypto API
+en/decryption).
+
+
+Constraints and notes
+=====================
+
+- IE hardware has a limited number of "keyslots" that can be programmed
+  with an encryption context (key, algorithm, data unit size, etc.) at any time.
+  One can specify a keyslot in a data request made to the device, and the
+  device will en/decrypt the data using the encryption context programmed into
+  that specified keyslot. When possible, we want to make multiple requests with
+  the same encryption context share the same keyslot.
+
+- We need a way for upper layers like filesystems to specify an encryption
+  context to use for en/decrypting a struct bio, and a device driver (like UFS)
+  needs to be able to use that encryption context when it processes the bio.
+
+- We need a way for device drivers to expose their inline encryption
+  capabilities in a unified way to the upper layers.
+
+
+Design
+======
+
+We add a :c:type:`struct bio_crypt_ctx` to :c:type:`struct bio` that can
+represent an encryption context, because we need to be able to pass this
+encryption context from the upper layers (like the fs layer) to the
+device driver to act upon.
+
+While IE hardware works on the notion of keyslots, the FS layer has no
+knowledge of keyslots - it simply wants to specify an encryption context to
+use while en/decrypting a bio.
+
+We introduce a keyslot manager (KSM) that handles the translation from
+encryption contexts specified by the FS to keyslots on the IE hardware.
+This KSM also serves as the way IE hardware can expose its capabilities to
+upper layers. The generic mode of operation is: each device driver that wants
+to support IE will construct a KSM and set it up in its struct request_queue.
+Upper layers that want to use IE on this device can then use this KSM in
+the device's struct request_queue to translate an encryption context into
+a keyslot. The presence of the KSM in the request queue shall be used to mean
+that the device supports IE.
+
+The KSM uses refcounts to track which keyslots are idle (either they have no
+encryption context programmed, or there are no in-flight struct bios
+referencing that keyslot). When a new encryption context needs a keyslot, it
+tries to find a keyslot that has already been programmed with the same
+encryption context, and if there is no such keyslot, it evicts the least
+recently used idle keyslot and programs the new encryption context into that
+one. If no idle keyslots are available, then the caller will sleep until there
+is at least one.
+
+
+blk-mq changes, other block layer changes and blk-crypto-fallback
+=================================================================
+
+We add a pointer to a ``bi_crypt_context`` and ``keyslot`` to
+:c:type:`struct request`. These will be referred to as the ``crypto fields``
+for the request. This ``keyslot`` is the keyslot into which the
+``bi_crypt_context`` has been programmed in the KSM of the ``request_queue``
+that this request is being sent to.
+
+We introduce ``block/blk-crypto-fallback.c``, which allows upper layers to remain
+blissfully unaware of whether or not real inline encryption hardware is present
+underneath. When a bio is submitted with a target ``request_queue`` that doesn't
+support the encryption context specified with the bio, the block layer will
+en/decrypt the bio with the blk-crypto-fallback.
+
+If the bio is a ``WRITE`` bio, a bounce bio is allocated, and the data in the bio
+is encrypted stored in the bounce bio - blk-mq will then proceed to process the
+bounce bio as if it were not encrypted at all (except when blk-integrity is
+concerned). ``blk-crypto-fallback`` sets the bounce bio's ``bi_end_io`` to an
+internal function that cleans up the bounce bio and ends the original bio.
+
+If the bio is a ``READ`` bio, the bio's ``bi_end_io`` (and also ``bi_private``)
+is saved and overwritten by ``blk-crypto-fallback`` to
+``bio_crypto_fallback_decrypt_bio``.  The bio's ``bi_crypt_context`` is also
+overwritten with ``NULL``, so that to the rest of the stack, the bio looks
+as if it was a regular bio that never had an encryption context specified.
+``bio_crypto_fallback_decrypt_bio`` will decrypt the bio, restore the original
+``bi_end_io`` (and also ``bi_private``) and end the bio again.
+
+Regardless of whether real inline encryption hardware is used or the
+blk-crypto-fallback is used, the ciphertext written to disk (and hence the
+on-disk format of data) will be the same (assuming the hardware's implementation
+of the algorithm being used adheres to spec and functions correctly).
+
+If a ``request queue``'s inline encryption hardware claimed to support the
+encryption context specified with a bio, then it will not be handled by the
+``blk-crypto-fallback``. We will eventually reach a point in blk-mq when a
+:c:type:`struct request` needs to be allocated for that bio. At that point,
+blk-mq tries to program the encryption context into the ``request_queue``'s
+keyslot_manager, and obtain a keyslot, which it stores in its newly added
+``keyslot`` field. This keyslot is released when the request is completed.
+
+When the first bio is added to a request, ``blk_crypto_rq_bio_prep`` is called,
+which sets the request's ``crypt_ctx`` to a copy of the bio's
+``bi_crypt_context``. bio_crypt_do_front_merge is called whenever a subsequent
+bio is merged to the front of the request, which updates the ``crypt_ctx`` of
+the request so that it matches the newly merged bio's ``bi_crypt_context``. In particular, the request keeps a copy of the ``bi_crypt_context`` of the first
+bio in its bio-list (blk-mq needs to be careful to maintain this invariant
+during bio and request merges).
+
+To make it possible for inline encryption to work with request queue based
+layered devices, when a request is cloned, its ``crypto fields`` are cloned as
+well. When the cloned request is submitted, blk-mq programs the
+``bi_crypt_context`` of the request into the clone's request_queue's keyslot
+manager, and stores the returned keyslot in the clone's ``keyslot``.
+
+
+API presented to users of the block layer
+=========================================
+
+``struct blk_crypto_key`` represents a crypto key (the raw key, size of the
+key, the crypto algorithm to use, the data unit size to use, and the number of
+bytes required to represent data unit numbers that will be specified with the
+``bi_crypt_context``).
+
+``blk_crypto_init_key`` allows upper layers to initialize such a
+``blk_crypto_key``.
+
+``bio_crypt_set_ctx`` should be called on any bio that a user of
+the block layer wants en/decrypted via inline encryption (or the
+blk-crypto-fallback, if hardware support isn't available for the desired
+crypto configuration). This function takes the ``blk_crypto_key`` and the
+data unit number (DUN) to use when en/decrypting the bio.
+
+``blk_crypto_config_supported`` allows upper layers to query whether or not the
+an encryption context passed to request queue can be handled by blk-crypto
+(either by real inline encryption hardware, or by the blk-crypto-fallback).
+This is useful e.g. when blk-crypto-fallback is disabled, and the upper layer
+wants to use an algorithm that may not supported by hardware - this function
+lets the upper layer know ahead of time that the algorithm isn't supported,
+and the upper layer can fallback to something else if appropriate.
+
+``blk_crypto_start_using_key`` - Upper layers must call this function on
+``blk_crypto_key`` and a ``request_queue`` before using the key with any bio
+headed for that ``request_queue``. This function ensures that either the
+hardware supports the key's crypto settings, or the crypto API fallback has
+transforms for the needed mode allocated and ready to go. Note that this
+function may allocate an ``skcipher``, and must not be called from the data
+path, since allocating ``skciphers`` from the data path can deadlock.
+
+``blk_crypto_evict_key`` *must* be called by upper layers before a
+``blk_crypto_key`` is freed. Further, it *must* only be called only once
+there are no more in-flight requests that use that ``blk_crypto_key``.
+``blk_crypto_evict_key`` will ensure that a key is removed from any keyslots in
+inline encryption hardware that the key might have been programmed into (or the blk-crypto-fallback).
+
+API presented to device drivers
+===============================
+
+A :c:type:``struct blk_keyslot_manager`` should be set up by device drivers in
+the ``request_queue`` of the device. The device driver needs to call
+``blk_ksm_init`` on the ``blk_keyslot_manager``, which specifying the number of
+keyslots supported by the hardware.
+
+The device driver also needs to tell the KSM how to actually manipulate the
+IE hardware in the device to do things like programming the crypto key into
+the IE hardware into a particular keyslot. All this is achieved through the
+:c:type:`struct blk_ksm_ll_ops` field in the KSM that the device driver
+must fill up after initing the ``blk_keyslot_manager``.
+
+The KSM also handles runtime power management for the device when applicable
+(e.g. when it wants to program a crypto key into the IE hardware, the device
+must be runtime powered on) - so the device driver must also set the ``dev``
+field in the ksm to point to the `struct device` for the KSM to use for runtime
+power management.
+
+``blk_ksm_reprogram_all_keys`` can be called by device drivers if the device
+needs each and every of its keyslots to be reprogrammed with the key it
+"should have" at the point in time when the function is called. This is useful
+e.g. if a device loses all its keys on runtime power down/up.
+
+``blk_ksm_destroy`` should be called to free up all resources used by a keyslot
+manager upon ``blk_ksm_init``, once the ``blk_keyslot_manager`` is no longer
+needed.
+
+
+Layered Devices
+===============
+
+Request queue based layered devices like dm-rq that wish to support IE need to
+create their own keyslot manager for their request queue, and expose whatever
+functionality they choose. When a layered device wants to pass a clone of that
+request to another ``request_queue``, blk-crypto will initialize and prepare the
+clone as necessary - see ``blk_crypto_insert_cloned_request`` in
+``blk-crypto.c``.
+
+
+Future Optimizations for layered devices
+========================================
+
+Creating a keyslot manager for a layered device uses up memory for each
+keyslot, and in general, a layered device merely passes the request on to a
+"child" device, so the keyslots in the layered device itself are completely
+unused, and don't need any refcounting or keyslot programming. We can instead
+define a new type of KSM; the "passthrough KSM", that layered devices can use
+to advertise an unlimited number of keyslots, and support for any encryption
+algorithms they choose, while not actually using any memory for each keyslot.
+Another use case for the "passthrough KSM" is for IE devices that do not have a
+limited number of keyslots.
+
+
+Interaction between inline encryption and blk integrity
+=======================================================
+
+At the time of this patch, there is no real hardware that supports both these
+features. However, these features do interact with each other, and it's not
+completely trivial to make them both work together properly. In particular,
+when a WRITE bio wants to use inline encryption on a device that supports both
+features, the bio will have an encryption context specified, after which
+its integrity information is calculated (using the plaintext data, since
+the encryption will happen while data is being written), and the data and
+integrity info is sent to the device. Obviously, the integrity info must be
+verified before the data is encrypted. After the data is encrypted, the device
+must not store the integrity info that it received with the plaintext data
+since that might reveal information about the plaintext data. As such, it must
+re-generate the integrity info from the ciphertext data and store that on disk
+instead. Another issue with storing the integrity info of the plaintext data is
+that it changes the on disk format depending on whether hardware inline
+encryption support is present or the kernel crypto API fallback is used (since
+if the fallback is used, the device will receive the integrity info of the
+ciphertext, not that of the plaintext).
+
+Because there isn't any real hardware yet, it seems prudent to assume that
+hardware implementations might not implement both features together correctly,
+and disallow the combination for now. Whenever a device supports integrity, the
+kernel will pretend that the device does not support hardware inline encryption
+(by essentially setting the keyslot manager in the request_queue of the device
+to NULL). When the crypto API fallback is enabled, this means that all bios with
+and encryption context will use the fallback, and IO will complete as usual.
+When the fallback is disabled, a bio with an encryption context will be failed.
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -146,6 +146,7 @@ config BLK_CGROUP_IOLATENCY
 config BLK_CGROUP_IOCOST
 	bool "Enable support for cost model based cgroup IO controller"
 	depends on BLK_CGROUP=y
+	select BLK_RQ_IO_DATA_LEN
 	select BLK_RQ_ALLOC_TIME
 	---help---
 	Enabling this option enables the .weight interface for cost
@@ -185,6 +186,23 @@ config BLK_SED_OPAL
 	Enabling this option enables users to setup/unlock/lock
 	Locking ranges for SED devices using the Opal protocol.

+config BLK_INLINE_ENCRYPTION
+	bool "Enable inline encryption support in block layer"
+	help
+	  Build the blk-crypto subsystem. Enabling this lets the
+	  block layer handle encryption, so users can take
+	  advantage of inline encryption hardware if present.
+
+config BLK_INLINE_ENCRYPTION_FALLBACK
+	bool "Enable crypto API fallback for blk-crypto"
+	depends on BLK_INLINE_ENCRYPTION
+	select CRYPTO
+	select CRYPTO_SKCIPHER
+	help
+	  Enabling this lets the block layer handle inline encryption
+	  by falling back to the kernel crypto API when inline
+	  encryption hardware is not present.
+
 menu "Partition Types"

 source "block/partitions/Kconfig"
--- a/block/Makefile
+++ b/block/Makefile
@@ -36,3 +36,5 @@ obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
 obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
 obj-$(CONFIG_BLK_SED_OPAL)	+= sed-opal.o
 obj-$(CONFIG_BLK_PM)		+= blk-pm.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o blk-crypto.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK)	+= blk-crypto-fallback.o
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -6073,7 +6073,7 @@ static struct bfq_queue *bfq_get_bfqq_handle_split(struct bfq_data *bfqd,
 * comments on bfq_init_rq for the reason behind this delayed
 * preparation.
 */
-static void bfq_prepare_request(struct request *rq, struct bio *bio)
+static void bfq_prepare_request(struct request *rq)
 {
 	/*
 	 * Regardless of whether we have an icq attached, we have to
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -42,6 +42,9 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 	struct bio_set *bs = bio->bi_pool;
 	unsigned inline_vecs;

+	if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
 		bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
 		inline_vecs = nr_vecs;
--- a/block/bio.c
+++ b/block/bio.c
@@ -18,6 +18,7 @@
 #include <linux/blk-cgroup.h>
 #include <linux/highmem.h>
 #include <linux/sched/sysctl.h>
+#include <linux/blk-crypto.h>

 #include <trace/events/block.h>
 #include "blk.h"
@@ -237,6 +238,8 @@ void bio_uninit(struct bio *bio)

 	if (bio_integrity(bio))
 		bio_integrity_free(bio);
+
+	bio_crypt_free_ctx(bio);
 }
 EXPORT_SYMBOL(bio_uninit);

@@ -708,6 +711,8 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)

 	__bio_clone_fast(b, bio);

+	bio_crypt_clone(b, bio, gfp_mask);
+
 	if (bio_integrity(bio)) {
 		int ret;

@@ -748,9 +753,14 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
 	return true;
 }

-static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
-		struct page *page, unsigned len, unsigned offset,
-		bool *same_page)
+/*
+ * Try to merge a page into a segment, while obeying the hardware segment
+ * size limit.  This is not for normal read/write bios, but for passthrough
+ * or Zone Append operations that we can't split.
+ */
+static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
+				 struct page *page, unsigned len,
+				 unsigned offset, bool *same_page)
 {
 	struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
 	unsigned long mask = queue_segment_boundary(q);
@@ -765,38 +775,32 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
 }

 /**
- *	__bio_add_pc_page	- attempt to add page to passthrough bio
- *	@q: the target queue
- *	@bio: destination bio
- *	@page: page to add
- *	@len: vec entry length
- *	@offset: vec entry offset
- *	@same_page: return if the merge happen inside the same page
+ * bio_add_hw_page - attempt to add a page to a bio with hw constraints
+ * @q: the target queue
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ * @max_sectors: maximum number of sectors that can be added
+ * @same_page: return if the segment has been merged inside the same page
 *
- *	Attempt to add a page to the bio_vec maplist. This can fail for a
- *	number of reasons, such as the bio being full or target block device
- *	limitations. The target block device must allow bio's up to PAGE_SIZE,
- *	so it is always possible to add a single page to an empty bio.
- *
- *	This should only be used by passthrough bios.
+ * Add a page to a bio while respecting the hardware max_sectors, max_segment
+ * and gap limitations.
 */
-int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
+int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		struct page *page, unsigned int len, unsigned int offset,
-		bool *same_page)
+		unsigned int max_sectors, bool *same_page)
 {
 	struct bio_vec *bvec;

-	/*
-	 * cloned bio must not modify vec list
-	 */
-	if (unlikely(bio_flagged(bio, BIO_CLONED)))
+	if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
 		return 0;

-	if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
+	if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
 		return 0;

 	if (bio->bi_vcnt > 0) {
-		if (bio_try_merge_pc_page(q, bio, page, len, offset, same_page))
+		if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
 			return len;

 		/*
@@ -823,11 +827,27 @@ int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
 	return len;
 }

+/**
+ * bio_add_pc_page	- attempt to add page to passthrough bio
+ * @q: the target queue
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * Attempt to add a page to the bio_vec maplist. This can fail for a
+ * number of reasons, such as the bio being full or target block device
+ * limitations. The target block device must allow bio's up to PAGE_SIZE,
+ * so it is always possible to add a single page to an empty bio.
+ *
+ * This should only be used by passthrough bios.
+ */
 int bio_add_pc_page(struct request_queue *q, struct bio *bio,
 		struct page *page, unsigned int len, unsigned int offset)
 {
 	bool same_page = false;
-	return __bio_add_pc_page(q, bio, page, len, offset, &same_page);
+	return bio_add_hw_page(q, bio, page, len, offset,
+			queue_max_hw_sectors(q), &same_page);
 }
 EXPORT_SYMBOL(bio_add_pc_page);

@@ -936,6 +956,7 @@ void bio_release_pages(struct bio *bio, bool mark_dirty)
 		put_page(bvec->bv_page);
 	}
 }
+EXPORT_SYMBOL_GPL(bio_release_pages);

 static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
 {
@@ -1010,6 +1031,50 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 	return 0;
 }

+static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
+{
+	unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
+	unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
+	struct request_queue *q = bio->bi_disk->queue;
+	unsigned int max_append_sectors = queue_max_zone_append_sectors(q);
+	struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
+	struct page **pages = (struct page **)bv;
+	ssize_t size, left;
+	unsigned len, i;
+	size_t offset;
+
+	if (WARN_ON_ONCE(!max_append_sectors))
+		return 0;
+
+	/*
+	 * Move page array up in the allocated memory for the bio vecs as far as
+	 * possible so that we can start filling biovecs from the beginning
+	 * without overwriting the temporary page array.
+	 */
+	BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
+	pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
+
+	size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
+	if (unlikely(size <= 0))
+		return size ? size : -EFAULT;
+
+	for (left = size, i = 0; left > 0; left -= len, i++) {
+		struct page *page = pages[i];
+		bool same_page = false;
+
+		len = min_t(size_t, PAGE_SIZE - offset, left);
+		if (bio_add_hw_page(q, bio, page, len, offset,
+				max_append_sectors, &same_page) != len)
+			return -EINVAL;
+		if (same_page)
+			put_page(page);
+		offset = 0;
+	}
+
+	iov_iter_advance(iter, size);
+	return 0;
+}
+
 /**
 * bio_iov_iter_get_pages - add user or kernel pages to a bio
 * @bio: bio to add pages to
@@ -1039,16 +1104,23 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 		return -EINVAL;

 	do {
-		if (is_bvec)
-			ret = __bio_iov_bvec_add_pages(bio, iter);
-		else
-			ret = __bio_iov_iter_get_pages(bio, iter);
+		if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
+			if (WARN_ON_ONCE(is_bvec))
+				return -EINVAL;
+			ret = __bio_iov_append_get_pages(bio, iter);
+		} else {
+			if (is_bvec)
+				ret = __bio_iov_bvec_add_pages(bio, iter);
+			else
+				ret = __bio_iov_iter_get_pages(bio, iter);
+		}
 	} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));

 	if (is_bvec)
 		bio_set_flag(bio, BIO_NO_PAGE_REF);
 	return bio->bi_vcnt ? 0 : ret;
 }
+EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);

 static void submit_bio_wait_endio(struct bio *bio)
 {
@@ -1105,6 +1177,7 @@ void bio_advance(struct bio *bio, unsigned bytes)
 	if (bio_integrity(bio))
 		bio_integrity_advance(bio, bytes);

+	bio_crypt_advance(bio, bytes);
 	bio_advance_iter(bio, &bio->bi_iter, bytes);
 }
 EXPORT_SYMBOL(bio_advance);
@@ -1303,55 +1376,6 @@ defer:
 	schedule_work(&bio_dirty_work);
 }

-void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)
-{
-	unsigned long stamp;
-again:
-	stamp = READ_ONCE(part->stamp);
-	if (unlikely(stamp != now)) {
-		if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) {
-			__part_stat_add(part, io_ticks, end ? now - stamp : 1);
-		}
-	}
-	if (part->partno) {
-		part = &part_to_disk(part)->part0;
-		goto again;
-	}
-}
-
-void generic_start_io_acct(struct request_queue *q, int op,
-			   unsigned long sectors, struct hd_struct *part)
-{
-	const int sgrp = op_stat_group(op);
-
-	part_stat_lock();
-
-	update_io_ticks(part, jiffies, false);
-	part_stat_inc(part, ios[sgrp]);
-	part_stat_add(part, sectors[sgrp], sectors);
-	part_inc_in_flight(q, part, op_is_write(op));
-
-	part_stat_unlock();
-}
-EXPORT_SYMBOL(generic_start_io_acct);
-
-void generic_end_io_acct(struct request_queue *q, int req_op,
-			 struct hd_struct *part, unsigned long start_time)
-{
-	unsigned long now = jiffies;
-	unsigned long duration = now - start_time;
-	const int sgrp = op_stat_group(req_op);
-
-	part_stat_lock();
-
-	update_io_ticks(part, now, true);
-	part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
-	part_dec_in_flight(q, part, op_is_write(req_op));
-
-	part_stat_unlock();
-}
-EXPORT_SYMBOL(generic_end_io_acct);
-
 static inline bool bio_remaining_done(struct bio *bio)
 {
 	/*
@@ -1445,6 +1469,10 @@ struct bio *bio_split(struct bio *bio, int sectors,
 	BUG_ON(sectors <= 0);
 	BUG_ON(sectors >= bio_sectors(bio));

+	/* Zone append commands cannot be split */
+	if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
+		return NULL;
+
 	split = bio_clone_fast(bio, gfp, bs);
 	if (!split)
 		return NULL;
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1530,6 +1530,10 @@ static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now)
 {
 	u64 old = atomic64_read(&blkg->delay_start);

+	/* negative use_delay means no scaling, see blkcg_set_delay() */
+	if (atomic_read(&blkg->use_delay) < 0)
+		return;
+
 	/*
 	 * We only want to scale down every second.  The idea here is that we
 	 * want to delay people for min(delay_nsec, NSEC_PER_SEC) in a certain
@@ -1717,6 +1721,8 @@ void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay)
 */
 void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta)
 {
+	if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
+		return;
 	blkcg_scale_delay(blkg, now);
 	atomic64_add(delta, &blkg->delay_nsec);
 }
--- a/block/blk-core.c
+++ b/block/blk-core.c
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
--- a/block/blk-crypto-internal.h
+++ b/block/blk-crypto-internal.h
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __LINUX_BLK_CRYPTO_INTERNAL_H
+#define __LINUX_BLK_CRYPTO_INTERNAL_H
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+
+/* Represents a crypto mode supported by blk-crypto  */
+struct blk_crypto_mode {
+	const char *cipher_str; /* crypto API name (for fallback case) */
+	unsigned int keysize; /* key size in bytes */
+	unsigned int ivsize; /* iv size in bytes */
+};
+
+extern const struct blk_crypto_mode blk_crypto_modes[];
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+
+void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
+			     unsigned int inc);
+
+bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio);
+
+bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
+			     struct bio_crypt_ctx *bc2);
+
+static inline bool bio_crypt_ctx_back_mergeable(struct request *req,
+						struct bio *bio)
+{
+	return bio_crypt_ctx_mergeable(req->crypt_ctx, blk_rq_bytes(req),
+				       bio->bi_crypt_context);
+}
+
+static inline bool bio_crypt_ctx_front_mergeable(struct request *req,
+						 struct bio *bio)
+{
+	return bio_crypt_ctx_mergeable(bio->bi_crypt_context,
+				       bio->bi_iter.bi_size, req->crypt_ctx);
+}
+
+static inline bool bio_crypt_ctx_merge_rq(struct request *req,
+					  struct request *next)
+{
+	return bio_crypt_ctx_mergeable(req->crypt_ctx, blk_rq_bytes(req),
+				       next->crypt_ctx);
+}
+
+static inline void blk_crypto_rq_set_defaults(struct request *rq)
+{
+	rq->crypt_ctx = NULL;
+	rq->crypt_keyslot = NULL;
+}
+
+static inline bool blk_crypto_rq_is_encrypted(struct request *rq)
+{
+	return rq->crypt_ctx;
+}
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+static inline bool bio_crypt_rq_ctx_compatible(struct request *rq,
+					       struct bio *bio)
+{
+	return true;
+}
+
+static inline bool bio_crypt_ctx_front_mergeable(struct request *req,
+						 struct bio *bio)
+{
+	return true;
+}
+
+static inline bool bio_crypt_ctx_back_mergeable(struct request *req,
+						struct bio *bio)
+{
+	return true;
+}
+
+static inline bool bio_crypt_ctx_merge_rq(struct request *req,
+					  struct request *next)
+{
+	return true;
+}
+
+static inline void blk_crypto_rq_set_defaults(struct request *rq) { }
+
+static inline bool blk_crypto_rq_is_encrypted(struct request *rq)
+{
+	return false;
+}
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+void __bio_crypt_advance(struct bio *bio, unsigned int bytes);
+static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
+{
+	if (bio_has_crypt_ctx(bio))
+		__bio_crypt_advance(bio, bytes);
+}
+
+void __bio_crypt_free_ctx(struct bio *bio);
+static inline void bio_crypt_free_ctx(struct bio *bio)
+{
+	if (bio_has_crypt_ctx(bio))
+		__bio_crypt_free_ctx(bio);
+}
+
+static inline void bio_crypt_do_front_merge(struct request *rq,
+					    struct bio *bio)
+{
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	if (bio_has_crypt_ctx(bio))
+		memcpy(rq->crypt_ctx->bc_dun, bio->bi_crypt_context->bc_dun,
+		       sizeof(rq->crypt_ctx->bc_dun));
+#endif
+}
+
+bool __blk_crypto_bio_prep(struct bio **bio_ptr);
+static inline bool blk_crypto_bio_prep(struct bio **bio_ptr)
+{
+	if (bio_has_crypt_ctx(*bio_ptr))
+		return __blk_crypto_bio_prep(bio_ptr);
+	return true;
+}
+
+blk_status_t __blk_crypto_init_request(struct request *rq);
+static inline blk_status_t blk_crypto_init_request(struct request *rq)
+{
+	if (blk_crypto_rq_is_encrypted(rq))
+		return __blk_crypto_init_request(rq);
+	return BLK_STS_OK;
+}
+
+void __blk_crypto_free_request(struct request *rq);
+static inline void blk_crypto_free_request(struct request *rq)
+{
+	if (blk_crypto_rq_is_encrypted(rq))
+		__blk_crypto_free_request(rq);
+}
+
+void __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
+			      gfp_t gfp_mask);
+static inline void blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
+					  gfp_t gfp_mask)
+{
+	if (bio_has_crypt_ctx(bio))
+		__blk_crypto_rq_bio_prep(rq, bio, gfp_mask);
+}
+
+/**
+ * blk_crypto_insert_cloned_request - Prepare a cloned request to be inserted
+ *				      into a request queue.
+ * @rq: the request being queued
+ *
+ * Return: BLK_STS_OK on success, nonzero on error.
+ */
+static inline blk_status_t blk_crypto_insert_cloned_request(struct request *rq)
+{
+
+	if (blk_crypto_rq_is_encrypted(rq))
+		return blk_crypto_init_request(rq);
+	return BLK_STS_OK;
+}
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK
+
+int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num);
+
+bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr);
+
+int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key);
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */
+
+static inline int
+blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
+{
+	pr_warn_once("crypto API fallback is disabled\n");
+	return -ENOPKG;
+}
+
+static inline bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
+{
+	pr_warn_once("crypto API fallback disabled; failing request.\n");
+	(*bio_ptr)->bi_status = BLK_STS_NOTSUPP;
+	return false;
+}
+
+static inline int
+blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
+{
+	return 0;
+}
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK */
+
+#endif /* __LINUX_BLK_CRYPTO_INTERNAL_H */
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -0,0 +1,404 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+/*
+ * Refer to Documentation/block/inline-encryption.rst for detailed explanation.
+ */
+
+#define pr_fmt(fmt) "blk-crypto: " fmt
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/keyslot-manager.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "blk-crypto-internal.h"
+
+const struct blk_crypto_mode blk_crypto_modes[] = {
+	[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
+		.cipher_str = "xts(aes)",
+		.keysize = 64,
+		.ivsize = 16,
+	},
+	[BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV] = {
+		.cipher_str = "essiv(cbc(aes),sha256)",
+		.keysize = 16,
+		.ivsize = 16,
+	},
+	[BLK_ENCRYPTION_MODE_ADIANTUM] = {
+		.cipher_str = "adiantum(xchacha12,aes)",
+		.keysize = 32,
+		.ivsize = 32,
+	},
+};
+
+/*
+ * This number needs to be at least (the number of threads doing IO
+ * concurrently) * (maximum recursive depth of a bio), so that we don't
+ * deadlock on crypt_ctx allocations. The default is chosen to be the same
+ * as the default number of post read contexts in both EXT4 and F2FS.
+ */
+static int num_prealloc_crypt_ctxs = 128;
+
+module_param(num_prealloc_crypt_ctxs, int, 0444);
+MODULE_PARM_DESC(num_prealloc_crypt_ctxs,
+		"Number of bio crypto contexts to preallocate");
+
+static struct kmem_cache *bio_crypt_ctx_cache;
+static mempool_t *bio_crypt_ctx_pool;
+
+static int __init bio_crypt_ctx_init(void)
+{
+	size_t i;
+
+	bio_crypt_ctx_cache = KMEM_CACHE(bio_crypt_ctx, 0);
+	if (!bio_crypt_ctx_cache)
+		goto out_no_mem;
+
+	bio_crypt_ctx_pool = mempool_create_slab_pool(num_prealloc_crypt_ctxs,
+						      bio_crypt_ctx_cache);
+	if (!bio_crypt_ctx_pool)
+		goto out_no_mem;
+
+	/* This is assumed in various places. */
+	BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
+
+	/* Sanity check that no algorithm exceeds the defined limits. */
+	for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) {
+		BUG_ON(blk_crypto_modes[i].keysize > BLK_CRYPTO_MAX_KEY_SIZE);
+		BUG_ON(blk_crypto_modes[i].ivsize > BLK_CRYPTO_MAX_IV_SIZE);
+	}
+
+	return 0;
+out_no_mem:
+	panic("Failed to allocate mem for bio crypt ctxs\n");
+}
+subsys_initcall(bio_crypt_ctx_init);
+
+void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
+		       const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], gfp_t gfp_mask)
+{
+	struct bio_crypt_ctx *bc = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+
+	bc->bc_key = key;
+	memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
+
+	bio->bi_crypt_context = bc;
+}
+
+void __bio_crypt_free_ctx(struct bio *bio)
+{
+	mempool_free(bio->bi_crypt_context, bio_crypt_ctx_pool);
+	bio->bi_crypt_context = NULL;
+}
+
+void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
+{
+	dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+	*dst->bi_crypt_context = *src->bi_crypt_context;
+}
+EXPORT_SYMBOL_GPL(__bio_crypt_clone);
+
+/* Increments @dun by @inc, treating @dun as a multi-limb integer. */
+void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
+			     unsigned int inc)
+{
+	int i;
+
+	for (i = 0; inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
+		dun[i] += inc;
+		/*
+		 * If the addition in this limb overflowed, then we need to
+		 * carry 1 into the next limb. Else the carry is 0.
+		 */
+		if (dun[i] < inc)
+			inc = 1;
+		else
+			inc = 0;
+	}
+}
+
+void __bio_crypt_advance(struct bio *bio, unsigned int bytes)
+{
+	struct bio_crypt_ctx *bc = bio->bi_crypt_context;
+
+	bio_crypt_dun_increment(bc->bc_dun,
+				bytes >> bc->bc_key->data_unit_size_bits);
+}
+
+/*
+ * Returns true if @bc->bc_dun plus @bytes converted to data units is equal to
+ * @next_dun, treating the DUNs as multi-limb integers.
+ */
+bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
+				 unsigned int bytes,
+				 const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
+{
+	int i;
+	unsigned int carry = bytes >> bc->bc_key->data_unit_size_bits;
+
+	for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
+		if (bc->bc_dun[i] + carry != next_dun[i])
+			return false;
+		/*
+		 * If the addition in this limb overflowed, then we need to
+		 * carry 1 into the next limb. Else the carry is 0.
+		 */
+		if ((bc->bc_dun[i] + carry) < carry)
+			carry = 1;
+		else
+			carry = 0;
+	}
+
+	/* If the DUN wrapped through 0, don't treat it as contiguous. */
+	return carry == 0;
+}
+
+/*
+ * Checks that two bio crypt contexts are compatible - i.e. that
+ * they are mergeable except for data_unit_num continuity.
+ */
+static bool bio_crypt_ctx_compatible(struct bio_crypt_ctx *bc1,
+				     struct bio_crypt_ctx *bc2)
+{
+	if (!bc1)
+		return !bc2;
+
+	return bc2 && bc1->bc_key == bc2->bc_key;
+}
+
+bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio)
+{
+	return bio_crypt_ctx_compatible(rq->crypt_ctx, bio->bi_crypt_context);
+}
+
+/*
+ * Checks that two bio crypt contexts are compatible, and also
+ * that their data_unit_nums are continuous (and can hence be merged)
+ * in the order @bc1 followed by @bc2.
+ */
+bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
+			     struct bio_crypt_ctx *bc2)
+{
+	if (!bio_crypt_ctx_compatible(bc1, bc2))
+		return false;
+
+	return !bc1 || bio_crypt_dun_is_contiguous(bc1, bc1_bytes, bc2->bc_dun);
+}
+
+/* Check that all I/O segments are data unit aligned. */
+static bool bio_crypt_check_alignment(struct bio *bio)
+{
+	const unsigned int data_unit_size =
+		bio->bi_crypt_context->bc_key->crypto_cfg.data_unit_size;
+	struct bvec_iter iter;
+	struct bio_vec bv;
+
+	bio_for_each_segment(bv, bio, iter) {
+		if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
+			return false;
+	}
+
+	return true;
+}
+
+blk_status_t __blk_crypto_init_request(struct request *rq)
+{
+	return blk_ksm_get_slot_for_key(rq->q->ksm, rq->crypt_ctx->bc_key,
+					&rq->crypt_keyslot);
+}
+
+/**
+ * __blk_crypto_free_request - Uninitialize the crypto fields of a request.
+ *
+ * @rq: The request whose crypto fields to uninitialize.
+ *
+ * Completely uninitializes the crypto fields of a request. If a keyslot has
+ * been programmed into some inline encryption hardware, that keyslot is
+ * released. The rq->crypt_ctx is also freed.
+ */
+void __blk_crypto_free_request(struct request *rq)
+{
+	blk_ksm_put_slot(rq->crypt_keyslot);
+	mempool_free(rq->crypt_ctx, bio_crypt_ctx_pool);
+	blk_crypto_rq_set_defaults(rq);
+}
+
+/**
+ * __blk_crypto_bio_prep - Prepare bio for inline encryption
+ *
+ * @bio_ptr: pointer to original bio pointer
+ *
+ * If the bio crypt context provided for the bio is supported by the underlying
+ * device's inline encryption hardware, do nothing.
+ *
+ * Otherwise, try to perform en/decryption for this bio by falling back to the
+ * kernel crypto API. When the crypto API fallback is used for encryption,
+ * blk-crypto may choose to split the bio into 2 - the first one that will
+ * continue to be processed and the second one that will be resubmitted via
+ * generic_make_request. A bounce bio will be allocated to encrypt the contents
+ * of the aforementioned "first one", and *bio_ptr will be updated to this
+ * bounce bio.
+ *
+ * Caller must ensure bio has bio_crypt_ctx.
+ *
+ * Return: true on success; false on error (and bio->bi_status will be set
+ *	   appropriately, and bio_endio() will have been called so bio
+ *	   submission should abort).
+ */
+bool __blk_crypto_bio_prep(struct bio **bio_ptr)
+{
+	struct bio *bio = *bio_ptr;
+	const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
+
+	/* Error if bio has no data. */
+	if (WARN_ON_ONCE(!bio_has_data(bio))) {
+		bio->bi_status = BLK_STS_IOERR;
+		goto fail;
+	}
+
+	if (!bio_crypt_check_alignment(bio)) {
+		bio->bi_status = BLK_STS_IOERR;
+		goto fail;
+	}
+
+	/*
+	 * Success if device supports the encryption context, or if we succeeded
+	 * in falling back to the crypto API.
+	 */
+	if (blk_ksm_crypto_cfg_supported(bio->bi_disk->queue->ksm,
+					 &bc_key->crypto_cfg))
+		return true;
+
+	if (blk_crypto_fallback_bio_prep(bio_ptr))
+		return true;
+fail:
+	bio_endio(*bio_ptr);
+	return false;
+}
+
+/**
+ * __blk_crypto_rq_bio_prep - Prepare a request's crypt_ctx when its first bio
+ *			      is inserted
+ *
+ * @rq: The request to prepare
+ * @bio: The first bio being inserted into the request
+ * @gfp_mask: gfp mask
+ */
+void __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
+			      gfp_t gfp_mask)
+{
+	if (!rq->crypt_ctx)
+		rq->crypt_ctx = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+	*rq->crypt_ctx = *bio->bi_crypt_context;
+}
+
+/**
+ * blk_crypto_init_key() - Prepare a key for use with blk-crypto
+ * @blk_key: Pointer to the blk_crypto_key to initialize.
+ * @raw_key: Pointer to the raw key. Must be the correct length for the chosen
+ *	     @crypto_mode; see blk_crypto_modes[].
+ * @crypto_mode: identifier for the encryption algorithm to use
+ * @dun_bytes: number of bytes that will be used to specify the DUN when this
+ *	       key is used
+ * @data_unit_size: the data unit size to use for en/decryption
+ *
+ * Return: 0 on success, -errno on failure.  The caller is responsible for
+ *	   zeroizing both blk_key and raw_key when done with them.
+ */
+int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
+			enum blk_crypto_mode_num crypto_mode,
+			unsigned int dun_bytes,
+			unsigned int data_unit_size)
+{
+	const struct blk_crypto_mode *mode;
+
+	memset(blk_key, 0, sizeof(*blk_key));
+
+	if (crypto_mode >= ARRAY_SIZE(blk_crypto_modes))
+		return -EINVAL;
+
+	mode = &blk_crypto_modes[crypto_mode];
+	if (mode->keysize == 0)
+		return -EINVAL;
+
+	if (dun_bytes == 0 || dun_bytes > BLK_CRYPTO_MAX_IV_SIZE)
+		return -EINVAL;
+
+	if (!is_power_of_2(data_unit_size))
+		return -EINVAL;
+
+	blk_key->crypto_cfg.crypto_mode = crypto_mode;
+	blk_key->crypto_cfg.dun_bytes = dun_bytes;
+	blk_key->crypto_cfg.data_unit_size = data_unit_size;
+	blk_key->data_unit_size_bits = ilog2(data_unit_size);
+	blk_key->size = mode->keysize;
+	memcpy(blk_key->raw, raw_key, mode->keysize);
+
+	return 0;
+}
+
+/*
+ * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
+ * request queue it's submitted to supports inline crypto, or the
+ * blk-crypto-fallback is enabled and supports the cfg).
+ */
+bool blk_crypto_config_supported(struct request_queue *q,
+				 const struct blk_crypto_config *cfg)
+{
+	return IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) ||
+	       blk_ksm_crypto_cfg_supported(q->ksm, cfg);
+}
+
+/**
+ * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device
+ * @key: A key to use on the device
+ * @q: the request queue for the device
+ *
+ * Upper layers must call this function to ensure that either the hardware
+ * supports the key's crypto settings, or the crypto API fallback has transforms
+ * for the needed mode allocated and ready to go. This function may allocate
+ * an skcipher, and *should not* be called from the data path, since that might
+ * cause a deadlock
+ *
+ * Return: 0 on success; -ENOPKG if the hardware doesn't support the key and
+ *	   blk-crypto-fallback is either disabled or the needed algorithm
+ *	   is disabled in the crypto API; or another -errno code.
+ */
+int blk_crypto_start_using_key(const struct blk_crypto_key *key,
+			       struct request_queue *q)
+{
+	if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
+		return 0;
+	return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
+}
+
+/**
+ * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
+ *			    it may have been programmed into
+ * @q: The request queue who's associated inline encryption hardware this key
+ *     might have been programmed into
+ * @key: The key to evict
+ *
+ * Upper layers (filesystems) must call this function to ensure that a key is
+ * evicted from any hardware that it might have been programmed into.  The key
+ * must not be in use by any in-flight IO when this function is called.
+ *
+ * Return: 0 on success or if key is not present in the q's ksm, -err on error.
+ */
+int blk_crypto_evict_key(struct request_queue *q,
+			 const struct blk_crypto_key *key)
+{
+	if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
+		return blk_ksm_evict_key(q->ksm, key);
+
+	/*
+	 * If the request queue's associated inline encryption hardware didn't
+	 * have support for the key, then the key might have been programmed
+	 * into the fallback keyslot manager, so try to evict from there.
+	 */
+	return blk_crypto_fallback_evict_key(key);
+}
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -55,7 +55,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 	rq->rq_disk = bd_disk;
 	rq->end_io = done;

-	blk_account_io_start(rq, true);
+	blk_account_io_start(rq);

 	/*
 	 * don't check dying flag for MQ because the request won't
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -258,7 +258,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 		blk_flush_complete_seq(rq, fq, seq, error);
 	}

-	fq->flush_queue_delayed = 0;
 	spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
 }

@@ -433,41 +432,20 @@ void blk_insert_flush(struct request *rq)
 * blkdev_issue_flush - queue a flush
 * @bdev:	blockdev to issue flush for
 * @gfp_mask:	memory allocation flags (for bio_alloc)
- * @error_sector:	error sector
 *
 * Description:
- *    Issue a flush for the block device in question. Caller can supply
- *    room for storing the error offset in case of a flush error, if they
- *    wish to.
+ *    Issue a flush for the block device in question.
 */
-int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
-		sector_t *error_sector)
+int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask)
 {
-	struct request_queue *q;
 	struct bio *bio;
 	int ret = 0;

-	if (bdev->bd_disk == NULL)
-		return -ENXIO;
-
-	q = bdev_get_queue(bdev);
-	if (!q)
-		return -ENXIO;
-
 	bio = bio_alloc(gfp_mask, 0);
 	bio_set_dev(bio, bdev);
 	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;

 	ret = submit_bio_wait(bio);
-
-	/*
-	 * The driver must store the error location in ->bi_sector, if
-	 * it supports it. For non-stacked drivers, this should be
-	 * copied from blk_rq_pos(rq).
-	 */
-	if (error_sector)
-		*error_sector = bio->bi_iter.bi_sector;
-
 	bio_put(bio);
 	return ret;
 }
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -409,6 +409,13 @@ void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template
 	bi->tag_size = template->tag_size;

 	disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	if (disk->queue->ksm) {
+		pr_warn("blk-integrity: Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n");
+		blk_ksm_unregister(disk->queue);
+	}
+#endif
 }
 EXPORT_SYMBOL(blk_integrity_register);

--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -260,6 +260,7 @@ enum {
 	VTIME_PER_SEC_SHIFT	= 37,
 	VTIME_PER_SEC		= 1LLU << VTIME_PER_SEC_SHIFT,
 	VTIME_PER_USEC		= VTIME_PER_SEC / USEC_PER_SEC,
+	VTIME_PER_NSEC		= VTIME_PER_SEC / NSEC_PER_SEC,

 	/* bound vrate adjustments within two orders of magnitude */
 	VRATE_MIN_PPM		= 10000,	/* 1% */
@@ -1206,14 +1207,14 @@ static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }

-static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
+static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now)
 {
 	struct ioc *ioc = iocg->ioc;
 	struct blkcg_gq *blkg = iocg_to_blkg(iocg);
 	u64 vtime = atomic64_read(&iocg->vtime);
 	u64 vmargin = ioc->margin_us * now->vrate;
 	u64 margin_ns = ioc->margin_us * NSEC_PER_USEC;
-	u64 expires, oexpires;
+	u64 delta_ns, expires, oexpires;
 	u32 hw_inuse;

 	lockdep_assert_held(&iocg->waitq.lock);
@@ -1236,15 +1237,10 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
 		return false;

 	/* use delay */
-	if (cost) {
-		u64 cost_ns = DIV64_U64_ROUND_UP(cost * NSEC_PER_USEC,
-						 now->vrate);
-		blkcg_add_delay(blkg, now->now_ns, cost_ns);
-	}
-	blkcg_use_delay(blkg);
-
-	expires = now->now_ns + DIV64_U64_ROUND_UP(vtime - now->vnow,
-						   now->vrate) * NSEC_PER_USEC;
+	delta_ns = DIV64_U64_ROUND_UP(vtime - now->vnow,
+				      now->vrate) * NSEC_PER_USEC;
+	blkcg_set_delay(blkg, delta_ns);
+	expires = now->now_ns + delta_ns;

 	/* if already active and close enough, don't bother */
 	oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer));
@@ -1265,7 +1261,7 @@ static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer)

 	spin_lock_irqsave(&iocg->waitq.lock, flags);
 	ioc_now(iocg->ioc, &now);
-	iocg_kick_delay(iocg, &now, 0);
+	iocg_kick_delay(iocg, &now);
 	spin_unlock_irqrestore(&iocg->waitq.lock, flags);

 	return HRTIMER_NORESTART;
@@ -1383,7 +1379,7 @@ static void ioc_timer_fn(struct timer_list *timer)
 		if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt) {
 			/* might be oversleeping vtime / hweight changes, kick */
 			iocg_kick_waitq(iocg, &now);
-			iocg_kick_delay(iocg, &now, 0);
+			iocg_kick_delay(iocg, &now);
 		} else if (iocg_is_idle(iocg)) {
 			/* no waiter and idle, deactivate */
 			iocg->last_inuse = iocg->inuse;
@@ -1543,19 +1539,39 @@ skip_surplus_transfers:
 	if (rq_wait_pct > RQ_WAIT_BUSY_PCT ||
 	    missed_ppm[READ] > ppm_rthr ||
 	    missed_ppm[WRITE] > ppm_wthr) {
+		/* clearly missing QoS targets, slow down vrate */
 		ioc->busy_level = max(ioc->busy_level, 0);
 		ioc->busy_level++;
 	} else if (rq_wait_pct <= RQ_WAIT_BUSY_PCT * UNBUSY_THR_PCT / 100 &&
 		   missed_ppm[READ] <= ppm_rthr * UNBUSY_THR_PCT / 100 &&
 		   missed_ppm[WRITE] <= ppm_wthr * UNBUSY_THR_PCT / 100) {
-		/* take action iff there is contention */
-		if (nr_shortages && !nr_lagging) {
+		/* QoS targets are being met with >25% margin */
+		if (nr_shortages) {
+			/*
+			 * We're throttling while the device has spare
+			 * capacity.  If vrate was being slowed down, stop.
+			 */
 			ioc->busy_level = min(ioc->busy_level, 0);
-			/* redistribute surpluses first */
-			if (!nr_surpluses)
+
+			/*
+			 * If there are IOs spanning multiple periods, wait
+			 * them out before pushing the device harder.  If
+			 * there are surpluses, let redistribution work it
+			 * out first.
+			 */
+			if (!nr_lagging && !nr_surpluses)
 				ioc->busy_level--;
+		} else {
+			/*
+			 * Nobody is being throttled and the users aren't
+			 * issuing enough IOs to saturate the device.  We
+			 * simply don't know how close the device is to
+			 * saturation.  Coast.
+			 */
+			ioc->busy_level = 0;
 		}
 	} else {
+		/* inside the hysterisis margin, we're good */
 		ioc->busy_level = 0;
 	}

@@ -1678,6 +1694,31 @@ static u64 calc_vtime_cost(struct bio *bio, struct ioc_gq *iocg, bool is_merge)
 	return cost;
 }

+static void calc_size_vtime_cost_builtin(struct request *rq, struct ioc *ioc,
+					 u64 *costp)
+{
+	unsigned int pages = blk_rq_stats_sectors(rq) >> IOC_SECT_TO_PAGE_SHIFT;
+
+	switch (req_op(rq)) {
+	case REQ_OP_READ:
+		*costp = pages * ioc->params.lcoefs[LCOEF_RPAGE];
+		break;
+	case REQ_OP_WRITE:
+		*costp = pages * ioc->params.lcoefs[LCOEF_WPAGE];
+		break;
+	default:
+		*costp = 0;
+	}
+}
+
+static u64 calc_size_vtime_cost(struct request *rq, struct ioc *ioc)
+{
+	u64 cost;
+
+	calc_size_vtime_cost_builtin(rq, ioc, &cost);
+	return cost;
+}
+
 static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 {
 	struct blkcg_gq *blkg = bio->bi_blkg;
@@ -1762,7 +1803,7 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 	 */
 	if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) {
 		iocg->abs_vdebt += abs_cost;
-		if (iocg_kick_delay(iocg, &now, cost))
+		if (iocg_kick_delay(iocg, &now))
 			blkcg_schedule_throttle(rqos->q,
 					(bio->bi_opf & REQ_SWAP) == REQ_SWAP);
 		spin_unlock_irq(&iocg->waitq.lock);
@@ -1850,7 +1891,7 @@ static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq,
 	spin_lock_irqsave(&iocg->waitq.lock, flags);
 	if (likely(!list_empty(&iocg->active_list))) {
 		iocg->abs_vdebt += abs_cost;
-		iocg_kick_delay(iocg, &now, cost);
+		iocg_kick_delay(iocg, &now);
 	} else {
 		iocg_commit_bio(iocg, bio, cost);
 	}
@@ -1868,7 +1909,7 @@ static void ioc_rqos_done_bio(struct rq_qos *rqos, struct bio *bio)
 static void ioc_rqos_done(struct rq_qos *rqos, struct request *rq)
 {
 	struct ioc *ioc = rqos_to_ioc(rqos);
-	u64 on_q_ns, rq_wait_ns;
+	u64 on_q_ns, rq_wait_ns, size_nsec;
 	int pidx, rw;

 	if (!ioc->enabled || !rq->alloc_time_ns || !rq->start_time_ns)
@@ -1889,8 +1930,10 @@ static void ioc_rqos_done(struct rq_qos *rqos, struct request *rq)

 	on_q_ns = ktime_get_ns() - rq->alloc_time_ns;
 	rq_wait_ns = rq->start_time_ns - rq->alloc_time_ns;
+	size_nsec = div64_u64(calc_size_vtime_cost(rq, ioc), VTIME_PER_NSEC);

-	if (on_q_ns <= ioc->params.qos[pidx] * NSEC_PER_USEC)
+	if (on_q_ns <= size_nsec ||
+	    on_q_ns - size_nsec <= ioc->params.qos[pidx] * NSEC_PER_USEC)
 		this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_met);
 	else
 		this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_missed);
@@ -2297,6 +2340,7 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
 	spin_lock_irq(&ioc->lock);

 	if (enable) {
+		blk_stat_enable_accounting(ioc->rqos.q);
 		blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q);
 		ioc->enabled = true;
 	} else {
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -257,6 +257,7 @@ out_bmd:
 static struct bio *bio_map_user_iov(struct request_queue *q,
 		struct iov_iter *iter, gfp_t gfp_mask)
 {
+	unsigned int max_sectors = queue_max_hw_sectors(q);
 	int j;
 	struct bio *bio;
 	int ret;
@@ -294,8 +295,8 @@ static struct bio *bio_map_user_iov(struct request_queue *q,
 				if (n > bytes)
 					n = bytes;

-				if (!__bio_add_pc_page(q, bio, page, n, offs,
-						&same_page)) {
+				if (!bio_add_hw_page(q, bio, page, n, offs,
+						     max_sectors, &same_page)) {
 					if (same_page)
 						put_page(page);
 					break;
@@ -549,6 +550,7 @@ int blk_rq_append_bio(struct request *rq, struct bio **bio)
 		rq->biotail->bi_next = *bio;
 		rq->biotail = *bio;
 		rq->__data_len += (*bio)->bi_iter.bi_size;
+		bio_crypt_free_ctx(*bio);
 	}

 	return 0;
@@ -654,8 +656,6 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 			bio = rq->bio;
 	} while (iov_iter_count(&i));

-	if (!bio_flagged(bio, BIO_USER_MAPPED))
-		rq->rq_flags |= RQF_COPY_USER;
 	return 0;

 unmap_rq:
@@ -731,7 +731,6 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 {
 	int reading = rq_data_dir(rq) == READ;
 	unsigned long addr = (unsigned long) kbuf;
-	int do_copy = 0;
 	struct bio *bio, *orig_bio;
 	int ret;

@@ -740,8 +739,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 	if (!len || !kbuf)
 		return -EINVAL;

-	do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
-	if (do_copy)
+	if (!blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf))
 		bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
 	else
 		bio = bio_map_kern(q, kbuf, len, gfp_mask);
@@ -752,9 +750,6 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 	bio->bi_opf &= ~REQ_OP_MASK;
 	bio->bi_opf |= req_op(rq);

-	if (do_copy)
-		rq->rq_flags |= RQF_COPY_USER;
-
 	orig_bio = bio;
 	ret = blk_rq_append_bio(rq, &bio);
 	if (unlikely(ret)) {
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -336,16 +336,6 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio,
 		/* there isn't chance to merge the splitted bio */
 		split->bi_opf |= REQ_NOMERGE;

-		/*
-		 * Since we're recursing into make_request here, ensure
-		 * that we mark this bio as already having entered the queue.
-		 * If not, and the queue is going away, we can get stuck
-		 * forever on waiting for the queue reference to drop. But
-		 * that will never happen, as we're already holding a
-		 * reference to it.
-		 */
-		bio_set_flag(*bio, BIO_QUEUE_ENTERED);
-
 		bio_chain(split, *bio);
 		trace_block_split(q, split, (*bio)->bi_iter.bi_sector);
 		generic_make_request(*bio);
@@ -519,44 +509,20 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
 * map a request to scatterlist, return number of sg entries setup. Caller
 * must make sure sg can hold rq->nr_phys_segments entries
 */
-int blk_rq_map_sg(struct request_queue *q, struct request *rq,
-		  struct scatterlist *sglist)
+int __blk_rq_map_sg(struct request_queue *q, struct request *rq,
+		struct scatterlist *sglist, struct scatterlist **last_sg)
 {
-	struct scatterlist *sg = NULL;
 	int nsegs = 0;

 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
-		nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, &sg);
+		nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, last_sg);
 	else if (rq->bio && bio_op(rq->bio) == REQ_OP_WRITE_SAME)
-		nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, &sg);
+		nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, last_sg);
 	else if (rq->bio)
-		nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg);
+		nsegs = __blk_bios_map_sg(q, rq->bio, sglist, last_sg);

-	if (unlikely(rq->rq_flags & RQF_COPY_USER) &&
-	    (blk_rq_bytes(rq) & q->dma_pad_mask)) {
-		unsigned int pad_len =
-			(q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
-
-		sg->length += pad_len;
-		rq->extra_len += pad_len;
-	}
-
-	if (q->dma_drain_size && q->dma_drain_needed(rq)) {
-		if (op_is_write(req_op(rq)))
-			memset(q->dma_drain_buffer, 0, q->dma_drain_size);
-
-		sg_unmark_end(sg);
-		sg = sg_next(sg);
-		sg_set_page(sg, virt_to_page(q->dma_drain_buffer),
-			    q->dma_drain_size,
-			    ((unsigned long)q->dma_drain_buffer) &
-			    (PAGE_SIZE - 1));
-		nsegs++;
-		rq->extra_len += q->dma_drain_size;
-	}
-
-	if (sg)
-		sg_mark_end(sg);
+	if (*last_sg)
+		sg_mark_end(*last_sg);

 	/*
 	 * Something must have been wrong if the figured number of
@@ -566,7 +532,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,

 	return nsegs;
 }
-EXPORT_SYMBOL(blk_rq_map_sg);
+EXPORT_SYMBOL(__blk_rq_map_sg);

 static inline int ll_new_hw_segment(struct request *req, struct bio *bio,
 		unsigned int nr_phys_segs)
@@ -596,6 +562,8 @@ int ll_back_merge_fn(struct request *req, struct bio *bio, unsigned int nr_segs)
 	if (blk_integrity_rq(req) &&
 	    integrity_req_gap_back_merge(req, bio))
 		return 0;
+	if (!bio_crypt_ctx_back_mergeable(req, bio))
+		return 0;
 	if (blk_rq_sectors(req) + bio_sectors(bio) >
 	    blk_rq_get_max_sectors(req, blk_rq_pos(req))) {
 		req_set_nomerge(req->q, req);
@@ -612,6 +580,8 @@ int ll_front_merge_fn(struct request *req, struct bio *bio, unsigned int nr_segs
 	if (blk_integrity_rq(req) &&
 	    integrity_req_gap_front_merge(req, bio))
 		return 0;
+	if (!bio_crypt_ctx_front_mergeable(req, bio))
+		return 0;
 	if (blk_rq_sectors(req) + bio_sectors(bio) >
 	    blk_rq_get_max_sectors(req, bio->bi_iter.bi_sector)) {
 		req_set_nomerge(req->q, req);
@@ -661,6 +631,9 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 	if (blk_integrity_merge_rq(q, req, next) == false)
 		return 0;

+	if (!bio_crypt_ctx_merge_rq(req, next))
+		return 0;
+
 	/* Merge is OK... */
 	req->nr_phys_segments = total_phys_segments;
 	return 1;
@@ -696,20 +669,17 @@ void blk_rq_set_mixed_merge(struct request *rq)
 	rq->rq_flags |= RQF_MIXED_MERGE;
 }

-static void blk_account_io_merge(struct request *req)
+static void blk_account_io_merge_request(struct request *req)
 {
 	if (blk_do_io_stat(req)) {
-		struct hd_struct *part;
-
 		part_stat_lock();
-		part = req->part;
-
-		part_dec_in_flight(req->q, part, rq_data_dir(req));
-
-		hd_struct_put(part);
+		part_stat_inc(req->part, merges[op_stat_group(req_op(req))]);
 		part_stat_unlock();
+
+		hd_struct_put(req->part);
 	}
 }
+
 /*
 * Two cases of handling DISCARD merge:
 * If max_discard_segments > 1, the driver takes every bio
@@ -821,7 +791,7 @@ static struct request *attempt_merge(struct request_queue *q,
 	/*
 	 * 'next' is going away, so update stats accordingly
 	 */
-	blk_account_io_merge(next);
+	blk_account_io_merge_request(next);

 	/*
 	 * ownership of bio passed from next to req, return 'next' for
@@ -885,6 +855,10 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
 		return false;

+	/* Only merge if the crypt contexts are compatible */
+	if (!bio_crypt_rq_ctx_compatible(rq, bio))
+		return false;
+
 	/* must be using the same buffer */
 	if (req_op(rq) == REQ_OP_WRITE_SAME &&
 	    !blk_write_same_mergeable(rq->bio, bio))
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -213,6 +213,7 @@ static const char *const hctx_state_name[] = {
 	HCTX_STATE_NAME(STOPPED),
 	HCTX_STATE_NAME(TAG_ACTIVE),
 	HCTX_STATE_NAME(SCHED_RESTART),
+	HCTX_STATE_NAME(INACTIVE),
 };
 #undef HCTX_STATE_NAME

@@ -239,6 +240,7 @@ static const char *const hctx_flag_name[] = {
 	HCTX_FLAG_NAME(TAG_SHARED),
 	HCTX_FLAG_NAME(BLOCKING),
 	HCTX_FLAG_NAME(NO_SCHED),
+	HCTX_FLAG_NAME(STACKING),
 };
 #undef HCTX_FLAG_NAME

@@ -292,7 +294,6 @@ static const char *const rqf_name[] = {
 	RQF_NAME(MQ_INFLIGHT),
 	RQF_NAME(DONTPREP),
 	RQF_NAME(PREEMPT),
-	RQF_NAME(COPY_USER),
 	RQF_NAME(FAILED),
 	RQF_NAME(QUIET),
 	RQF_NAME(ELVPRIV),
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -80,16 +80,22 @@ void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx)
 	blk_mq_run_hw_queue(hctx, true);
 }

+#define BLK_MQ_BUDGET_DELAY	3		/* ms units */
+
 /*
 * Only SCSI implements .get_budget and .put_budget, and SCSI restarts
 * its queue by itself in its completion handler, so we don't need to
 * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE.
+ *
+ * Returns -EAGAIN if hctx->dispatch was found non-empty and run_work has to
+ * be run again.  This is necessary to avoid starving flushes.
 */
-static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
+static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 {
 	struct request_queue *q = hctx->queue;
 	struct elevator_queue *e = q->elevator;
 	LIST_HEAD(rq_list);
+	int ret = 0;

 	do {
 		struct request *rq;
@@ -97,12 +103,25 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 		if (e->type->ops.has_work && !e->type->ops.has_work(hctx))
 			break;

+		if (!list_empty_careful(&hctx->dispatch)) {
+			ret = -EAGAIN;
+			break;
+		}
+
 		if (!blk_mq_get_dispatch_budget(hctx))
 			break;

 		rq = e->type->ops.dispatch_request(hctx);
 		if (!rq) {
 			blk_mq_put_dispatch_budget(hctx);
+			/*
+			 * We're releasing without dispatching. Holding the
+			 * budget could have blocked any "hctx"s with the
+			 * same queue and if we didn't dispatch then there's
+			 * no guarantee anyone will kick the queue.  Kick it
+			 * ourselves.
+			 */
+			blk_mq_delay_run_hw_queues(q, BLK_MQ_BUDGET_DELAY);
 			break;
 		}

@@ -113,6 +132,8 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 		 */
 		list_add(&rq->queuelist, &rq_list);
 	} while (blk_mq_dispatch_rq_list(q, &rq_list, true));
+
+	return ret;
 }

 static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx,
@@ -130,16 +151,25 @@ static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx,
 * Only SCSI implements .get_budget and .put_budget, and SCSI restarts
 * its queue by itself in its completion handler, so we don't need to
 * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE.
+ *
+ * Returns -EAGAIN if hctx->dispatch was found non-empty and run_work has to
+ * to be run again.  This is necessary to avoid starving flushes.
 */
-static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
+static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 {
 	struct request_queue *q = hctx->queue;
 	LIST_HEAD(rq_list);
 	struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from);
+	int ret = 0;

 	do {
 		struct request *rq;

+		if (!list_empty_careful(&hctx->dispatch)) {
+			ret = -EAGAIN;
+			break;
+		}
+
 		if (!sbitmap_any_bit_set(&hctx->ctx_map))
 			break;

@@ -149,6 +179,14 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 		rq = blk_mq_dequeue_from_ctx(hctx, ctx);
 		if (!rq) {
 			blk_mq_put_dispatch_budget(hctx);
+			/*
+			 * We're releasing without dispatching. Holding the
+			 * budget could have blocked any "hctx"s with the
+			 * same queue and if we didn't dispatch then there's
+			 * no guarantee anyone will kick the queue.  Kick it
+			 * ourselves.
+			 */
+			blk_mq_delay_run_hw_queues(q, BLK_MQ_BUDGET_DELAY);
 			break;
 		}

@@ -165,21 +203,17 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 	} while (blk_mq_dispatch_rq_list(q, &rq_list, true));

 	WRITE_ONCE(hctx->dispatch_from, ctx);
+	return ret;
 }

-void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
+static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 {
 	struct request_queue *q = hctx->queue;
 	struct elevator_queue *e = q->elevator;
 	const bool has_sched_dispatch = e && e->type->ops.dispatch_request;
+	int ret = 0;
 	LIST_HEAD(rq_list);

-	/* RCU or SRCU read lock is needed before checking quiesced flag */
-	if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)))
-		return;
-
-	hctx->run++;
-
 	/*
 	 * If we have previous entries on our dispatch list, grab them first for
 	 * more fair dispatch.
@@ -208,19 +242,41 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 		blk_mq_sched_mark_restart_hctx(hctx);
 		if (blk_mq_dispatch_rq_list(q, &rq_list, false)) {
 			if (has_sched_dispatch)
-				blk_mq_do_dispatch_sched(hctx);
+				ret = blk_mq_do_dispatch_sched(hctx);
 			else
-				blk_mq_do_dispatch_ctx(hctx);
+				ret = blk_mq_do_dispatch_ctx(hctx);
 		}
 	} else if (has_sched_dispatch) {
-		blk_mq_do_dispatch_sched(hctx);
+		ret = blk_mq_do_dispatch_sched(hctx);
 	} else if (hctx->dispatch_busy) {
 		/* dequeue request one by one from sw queue if queue is busy */
-		blk_mq_do_dispatch_ctx(hctx);
+		ret = blk_mq_do_dispatch_ctx(hctx);
 	} else {
 		blk_mq_flush_busy_ctxs(hctx, &rq_list);
 		blk_mq_dispatch_rq_list(q, &rq_list, false);
 	}
+
+	return ret;
+}
+
+void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
+{
+	struct request_queue *q = hctx->queue;
+
+	/* RCU or SRCU read lock is needed before checking quiesced flag */
+	if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)))
+		return;
+
+	hctx->run++;
+
+	/*
+	 * A return of -EAGAIN is an indication that hctx->dispatch is not
+	 * empty and we must run again in order to avoid starving flushes.
+	 */
+	if (__blk_mq_sched_dispatch_requests(hctx) == -EAGAIN) {
+		if (__blk_mq_sched_dispatch_requests(hctx) == -EAGAIN)
+			blk_mq_run_hw_queue(hctx, true);
+	}
 }

 bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
--- a/Show More
+++ b/Show More