Pull XArray updates from Matthew Wilcox:
- Documentation update
- Fix test-suite build after move of bitmap.h
- Fix xas_create_range() when a large entry is already present
- Fix xas_split() of a shadow entry
* tag 'xarray-5.18' of git://git.infradead.org/users/willy/xarray:
XArray: Update the LRU list in xas_split()
XArray: Fix xas_create_range() when multi-order entry present
XArray: Include bitmap.h from xarray.h
XArray: Document the locking requirement for the xa_state
This reverts commit aa6f8dcbab.
It turns out this breaks at least the ath9k wireless driver, and
possibly others.
What the ath9k driver does on packet receive is to set up the DMA
transfer with:
int ath_rx_init(..)
..
bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
common->rx_bufsize,
DMA_FROM_DEVICE);
and then the receive logic (through ath_rx_tasklet()) will fetch
incoming packets
static bool ath_edma_get_buffers(..)
..
dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
common->rx_bufsize, DMA_FROM_DEVICE);
ret = ath9k_hw_process_rxdesc_edma(ah, rs, skb->data);
if (ret == -EINPROGRESS) {
/*let device gain the buffer again*/
dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
common->rx_bufsize, DMA_FROM_DEVICE);
return false;
}
and it's worth noting how that first DMA sync:
dma_sync_single_for_cpu(..DMA_FROM_DEVICE);
is there to make sure the CPU can read the DMA buffer (possibly by
copying it from the bounce buffer area, or by doing some cache flush).
The iommu correctly turns that into a "copy from bounce bufer" so that
the driver can look at the state of the packets.
In the meantime, the device may continue to write to the DMA buffer, but
we at least have a snapshot of the state due to that first DMA sync.
But that _second_ DMA sync:
dma_sync_single_for_device(..DMA_FROM_DEVICE);
is telling the DMA mapping that the CPU wasn't interested in the area
because the packet wasn't there. In the case of a DMA bounce buffer,
that is a no-op.
Note how it's not a sync for the CPU (the "for_device()" part), and it's
not a sync for data written by the CPU (the "DMA_FROM_DEVICE" part).
Or rather, it _should_ be a no-op. That's what commit aa6f8dcbab
broke: it made the code bounce the buffer unconditionally, and changed
the DMA_FROM_DEVICE to just unconditionally and illogically be
DMA_TO_DEVICE.
[ Side note: purely within the confines of the swiotlb driver it wasn't
entirely illogical: The reason it did that odd DMA_FROM_DEVICE ->
DMA_TO_DEVICE conversion thing is because inside the swiotlb driver,
it uses just a swiotlb_bounce() helper that doesn't care about the
whole distinction of who the sync is for - only which direction to
bounce.
So it took the "sync for device" to mean that the CPU must have been
the one writing, and thought it meant DMA_TO_DEVICE. ]
Also note how the commentary in that commit was wrong, probably due to
that whole confusion, claiming that the commit makes the swiotlb code
"bounce unconditionally (that is, also
when dir == DMA_TO_DEVICE) in order do avoid synchronising back stale
data from the swiotlb buffer"
which is nonsensical for two reasons:
- that "also when dir == DMA_TO_DEVICE" is nonsensical, as that was
exactly when it always did - and should do - the bounce.
- since this is a sync for the device (not for the CPU), we're clearly
fundamentally not coping back stale data from the bounce buffers at
all, because we'd be copying *to* the bounce buffers.
So that commit was just very confused. It confused the direction of the
synchronization (to the device, not the cpu) with the direction of the
DMA (from the device).
Reported-and-bisected-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reported-by: Olha Cherevyk <olha.cherevyk@gmail.com>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Toke Høiland-Jørgensen <toke@toke.dk>
Cc: Maxime Bizon <mbizon@freebox.fr>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull folio updates from Matthew Wilcox:
- Rewrite how munlock works to massively reduce the contention on
i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew
Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
mm/damon: minor cleanup for damon_pa_young
selftests/vm/transhuge-stress: Support file-backed PMD folios
mm/filemap: Support VM_HUGEPAGE for file mappings
mm/readahead: Switch to page_cache_ra_order
mm/readahead: Align file mappings for non-DAX
mm/readahead: Add large folio readahead
mm: Support arbitrary THP sizes
mm: Make large folios depend on THP
mm: Fix READ_ONLY_THP warning
mm/filemap: Allow large folios to be added to the page cache
mm: Turn can_split_huge_page() into can_split_folio()
mm/vmscan: Convert pageout() to take a folio
mm/vmscan: Turn page_check_references() into folio_check_references()
mm/vmscan: Account large folios correctly
mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
mm/vmscan: Free non-shmem folios without splitting them
mm/rmap: Constify the rmap_walk_control argument
mm/rmap: Convert rmap_walk() to take a folio
mm: Turn page_anon_vma() into folio_anon_vma()
mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
...
Move compound_pincount from the third page to the second page, which
means it's available for all compound pages. That lets us delete
hpage_pincount_available().
On 32-bit systems, there isn't enough space for both compound_pincount
and compound_nr in the second page (it would collide with page->private,
which is in use for pages in the swap cache), so revert the optimisation
of storing both compound_order and compound_nr on 32-bit systems.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Unfortunately, we ended up merging an old version of the patch "fix info
leak with DMA_FROM_DEVICE" instead of merging the latest one. Christoph
(the swiotlb maintainer), he asked me to create an incremental fix
(after I have pointed this out the mix up, and asked him for guidance).
So here we go.
The main differences between what we got and what was agreed are:
* swiotlb_sync_single_for_device is also required to do an extra bounce
* We decided not to introduce DMA_ATTR_OVERWRITE until we have exploiters
* The implantation of DMA_ATTR_OVERWRITE is flawed: DMA_ATTR_OVERWRITE
must take precedence over DMA_ATTR_SKIP_CPU_SYNC
Thus this patch removes DMA_ATTR_OVERWRITE, and makes
swiotlb_sync_single_for_device() bounce unconditionally (that is, also
when dir == DMA_TO_DEVICE) in order do avoid synchronising back stale
data from the swiotlb buffer.
Let me note, that if the size used with dma_sync_* API is less than the
size used with dma_[un]map_*, under certain circumstances we may still
end up with swiotlb not being transparent. In that sense, this is no
perfect fix either.
To get this bullet proof, we would have to bounce the entire
mapping/bounce buffer. For that we would have to figure out the starting
address, and the size of the mapping in
swiotlb_sync_single_for_device(). While this does seem possible, there
seems to be no firm consensus on how things are supposed to work.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: ddbd89deb7 ("swiotlb: fix info leak with DMA_FROM_DEVICE")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem I'm addressing was discovered by the LTP test covering
cve-2018-1000204.
A short description of what happens follows:
1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO
interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV
and a corresponding dxferp. The peculiar thing about this is that TUR
is not reading from the device.
2) In sg_start_req() the invocation of blk_rq_map_user() effectively
bounces the user-space buffer. As if the device was to transfer into
it. Since commit a45b599ad8 ("scsi: sg: allocate with __GFP_ZERO in
sg_build_indirect()") we make sure this first bounce buffer is
allocated with GFP_ZERO.
3) For the rest of the story we keep ignoring that we have a TUR, so the
device won't touch the buffer we prepare as if the we had a
DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device
and the buffer allocated by SG is mapped by the function
virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here
scatter-gather and not scsi generics). This mapping involves bouncing
via the swiotlb (we need swiotlb to do virtio in protected guest like
s390 Secure Execution, or AMD SEV).
4) When the SCSI TUR is done, we first copy back the content of the second
(that is swiotlb) bounce buffer (which most likely contains some
previous IO data), to the first bounce buffer, which contains all
zeros. Then we copy back the content of the first bounce buffer to
the user-space buffer.
5) The test case detects that the buffer, which it zero-initialized,
ain't all zeros and fails.
One can argue that this is an swiotlb problem, because without swiotlb
we leak all zeros, and the swiotlb should be transparent in a sense that
it does not affect the outcome (if all other participants are well
behaved).
Copying the content of the original buffer into the swiotlb buffer is
the only way I can think of to make swiotlb transparent in such
scenarios. So let's do just that if in doubt, but allow the driver
to tell us that the whole mapped buffer is going to be overwritten,
in which case we can preserve the old behavior and avoid the performance
impact of the extra bounce.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
It wasn't obvious to all readers that it's unsafe to reuse an xa_state
after dropping the xas_lock() or the rcu_read_lock().
Reported-by: Charan Teja Kalla <charante@codeaurora.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
The entry/exit handling for exceptions, interrupts, syscalls and KVM is
not really documented except for some comments.
Fill the gaps.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de
Co-developed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
----
Changes since v3:
- s/nointr/noinstr/
Changes since v2:
- No big content changes, just style corrections, so it should be
pretty clean at this stage. In the light of this, I kept Mark's
Reviewed-by.
- Paul's style and paragraph re-writes
- Randy's style comments
- Add links to transition type sections
Documentation/core-api/entry.rst | 261 +++++++++++++++++++++++++++++++
Documentation/core-api/index.rst | 8 +
2 files changed, 269 insertions(+)
create mode 100644 Documentation/core-api/entry.rst
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220110105044.94423-1-nsaenzju@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull iomap updates from Matthew Wilcox:
"Convert xfs/iomap to use folios.
This should be all that is needed for XFS to use large folios. There
is no code in this pull request to create large folios, but no
additional changes should be needed to XFS or iomap once they are
created.
Usually this would have come from Darrick, and we had intended that it
would come that route. Between the holidays and various things which
Darrick needed to work on, he asked if I could send things directly.
There weren't any other iomap patches pending for this release, which
probably also played a role"
* tag 'iomap-5.17' of git://git.infradead.org/users/willy/linux: (26 commits)
iomap: Inline __iomap_zero_iter into its caller
xfs: Support large folios
iomap: Support large folios in invalidatepage
iomap: Convert iomap_migrate_page() to use folios
iomap: Convert iomap_add_to_ioend() to take a folio
iomap: Simplify iomap_do_writepage()
iomap: Simplify iomap_writepage_map()
iomap,xfs: Convert ->discard_page to ->discard_folio
iomap: Convert iomap_write_end_inline to take a folio
iomap: Convert iomap_write_begin() and iomap_write_end() to folios
iomap: Convert __iomap_zero_iter to use a folio
iomap: Allow iomap_write_begin() to be called with the full length
iomap: Convert iomap_page_mkwrite to use a folio
iomap: Convert readahead and readpage to use a folio
iomap: Convert iomap_read_inline_data to take a folio
iomap: Use folio offsets instead of page offsets
iomap: Convert bio completions to use folios
iomap: Pass the iomap_page into iomap_set_range_uptodate
iomap: Add iomap_invalidate_folio
iomap: Convert iomap_releasepage to use a folio
...
Pull driver core updates from Greg KH:
"Here is the set of changes for the driver core for 5.17-rc1.
Lots of little things here, including:
- kobj_type cleanups
- auxiliary_bus documentation updates
- auxiliary_device conversions for some drivers (relevant subsystems
all have provided acks for these)
- kernfs lock contention reduction for some workloads
- other tiny cleanups and changes.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (43 commits)
kobject documentation: remove default_attrs information
drivers/firmware: Add missing platform_device_put() in sysfb_create_simplefb
debugfs: lockdown: Allow reading debugfs files that are not world readable
driver core: Make bus notifiers in right order in really_probe()
driver core: Move driver_sysfs_remove() after driver_sysfs_add()
firmware: edd: remove empty default_attrs array
firmware: dmi-sysfs: use default_groups in kobj_type
qemu_fw_cfg: use default_groups in kobj_type
firmware: memmap: use default_groups in kobj_type
sh: sq: use default_groups in kobj_type
headers/uninline: Uninline single-use function: kobject_has_children()
devtmpfs: mount with noexec and nosuid
driver core: Simplify async probe test code by using ktime_ms_delta()
nilfs2: use default_groups in kobj_type
kobject: remove kset from struct kset_uevent_ops callbacks
driver core: make kobj_type constant.
driver core: platform: document registration-failure requirement
vdpa/mlx5: Use auxiliary_device driver data helpers
net/mlx5e: Use auxiliary_device driver data helpers
soundwire: intel: Use auxiliary_device driver data helpers
...
Allow callers to iterate over each folio instead of each page. The
bio need not have been constructed using folios originally.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
Pull workqueue updates from Tejun Heo:
"Nothing too interesting. An optimization to short-circuit noop cpumask
updates, debug dump code reorg, and doc update"
* 'for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: doc: Call out the non-reentrance conditions
workqueue: Introduce show_one_worker_pool and show_one_workqueue.
workqueue: make sysfs of unbound kworker cpumask more clever
Pull printk updates from Petr Mladek:
- Extend %pGp print format to print hex value of the page flags
- Use kvmalloc instead of kmalloc to allocate devkmsg buffers
- Misc cleanup and warning fixes
* tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
vsprintf: Update %pGp documentation about that it prints hex value
lib/vsprintf.c: Amend static asserts for format specifier flags
vsprintf: Make %pGp print the hex value
test_printf: Append strings more efficiently
test_printf: Remove custom appending of '|'
test_printf: Remove separate page_flags variable
test_printf: Make pft array const
ia64: don't do IA64_CMPXCHG_DEBUG without CONFIG_PRINTK
printk: use gnu_printf format attribute for printk_sprint()
printk: avoid -Wsometimes-uninitialized warning
printk: use kvmalloc instead of kmalloc for devkmsg_user
Pull irq updates from Thomas Gleixner:
"Updates for the interrupt subsystem:
Core changes:
- Prevent a potential deadlock when initial priority is assigned to a
newly created interrupt thread. A recent change to plug a race
between cpuset and __sched_setscheduler() introduced a new lock
dependency which is now triggered. Break the lock dependency chain
by moving the priority assignment to the thread function.
- A couple of small updates to make the irq core RT safe.
- Confine the irq_cpu_online/offline() API to the only left unfixable
user Cavium Octeon so that it does not grow new usage.
- A small documentation update
Driver changes:
- A large cross architecture rework to move irq_enter/exit() into the
architecture code to make addressing the NOHZ_FULL/RCU issues
simpler.
- The obligatory new irq chip driver for Microchip EIC
- Modularize a few irq chip drivers
- Expand usage of devm_*() helpers throughout the driver code
- The usual small fixes and improvements all over the place"
* tag 'irq-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
h8300: Fix linux/irqchip.h include mess
dt-bindings: irqchip: renesas-irqc: Document r8a774e1 bindings
MIPS: irq: Avoid an unused-variable error
genirq: Hide irq_cpu_{on,off}line() behind a deprecated option
irqchip/mips-gic: Get rid of the reliance on irq_cpu_online()
MIPS: loongson64: Drop call to irq_cpu_offline()
irq: remove handle_domain_{irq,nmi}()
irq: remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: riscv: perform irqentry in entry code
irq: openrisc: perform irqentry in entry code
irq: csky: perform irqentry in entry code
irq: arm64: perform irqentry in entry code
irq: arm: perform irqentry in entry code
irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: nds32: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: add generic_handle_arch_irq()
irq: unexport handle_irq_desc()
irq: simplify handle_domain_{irq,nmi}()
irq: mips: simplify do_domain_IRQ()
...
