Merge branch 'for-linus' into for-next

Merged upstream branch to make further fireworks development easier
(and avoid conflicts earlier).

Conflicts:
	sound/firewire/bebob/bebob_focusrite.c

Documentation/arm64/memory.txt

@@ -17,7 +17,7 @@ User addresses have bits 63:48 set to 0 while the kernel addresses have
 the same bits set to 1. TTBRx selection is given by bit 63 of the
 virtual address. The swapper_pg_dir contains only kernel (global)
 mappings while the user pgd contains only user (non-global) mappings.
-The swapper_pgd_dir address is written to TTBR1 and never written to
+The swapper_pg_dir address is written to TTBR1 and never written to
 TTBR0.
 
 

Documentation/devicetree/bindings/mailbox/mailbox.txt

@@ -0,0 +1,38 @@
+* Generic Mailbox Controller and client driver bindings
+
+Generic binding to provide a way for Mailbox controller drivers to
+assign appropriate mailbox channel to client drivers.
+
+* Mailbox Controller
+
+Required property:
+- #mbox-cells: Must be at least 1. Number of cells in a mailbox
+		specifier.
+
+Example:
+	mailbox: mailbox {
+		...
+		#mbox-cells = <1>;
+	};
+
+
+* Mailbox Client
+
+Required property:
+- mboxes: List of phandle and mailbox channel specifiers.
+
+Optional property:
+- mbox-names: List of identifier strings for each mailbox channel
+		required by the client. The use of this property
+		is discouraged in favor of using index in list of
+		'mboxes' while requesting a mailbox. Instead the
+		platforms may define channel indices, in DT headers,
+		to something legible.
+
+Example:
+	pwr_cntrl: power {
+		...
+		mbox-names = "pwr-ctrl", "rpc";
+		mboxes = <&mailbox 0
+			&mailbox 1>;
+	};

Documentation/devicetree/bindings/pwm/pwm-fsl-ftm.txt

@@ -1,5 +1,20 @@
 Freescale FlexTimer Module (FTM) PWM controller
 
+The same FTM PWM device can have a different endianness on different SoCs. The
+device tree provides a property to describing this so that an operating system
+device driver can handle all variants of the device. Refer to the table below
+for the endianness of the FTM PWM block as integrated into the existing SoCs:
+
+	SoC     | FTM-PWM endianness
+	--------+-------------------
+	Vybrid  | LE
+	LS1     | BE
+	LS2     | LE
+
+Please see ../regmap/regmap.txt for more detail about how to specify endian
+modes in device tree.
+
+
 Required properties:
 - compatible: Should be "fsl,vf610-ftm-pwm".
 - reg: Physical base address and length of the controller's registers
@@ -16,7 +31,8 @@ Required properties:
 - pinctrl-names: Must contain a "default" entry.
 - pinctrl-NNN: One property must exist for each entry in pinctrl-names.
   See pinctrl/pinctrl-bindings.txt for details of the property values.
-
+- big-endian: Boolean property, required if the FTM PWM registers use a big-
+  endian rather than little-endian layout.
 
 Example:
 
@@ -32,4 +48,5 @@ pwm0: pwm@40038000 {
 			<&clks VF610_CLK_FTM0_EXT_FIX_EN>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&pinctrl_pwm0_1>;
+		big-endian;
 };

Documentation/devicetree/bindings/pwm/pwm-rockchip.txt

@@ -7,8 +7,8 @@ Required properties:
    "rockchip,vop-pwm": found integrated in VOP on RK3288 SoC
  - reg: physical base address and length of the controller's registers
  - clocks: phandle and clock specifier of the PWM reference clock
- - #pwm-cells: should be 2. See pwm.txt in this directory for a
-   description of the cell format.
+ - #pwm-cells: must be 2 (rk2928) or 3 (rk3288). See pwm.txt in this directory
+   for a description of the cell format.
 
 Example:
 

Documentation/devicetree/bindings/sound/sgtl5000.txt

@@ -7,10 +7,20 @@ Required properties:
 
 - clocks : the clock provider of SYS_MCLK
 
+- VDDA-supply : the regulator provider of VDDA
+
+- VDDIO-supply: the regulator provider of VDDIO
+
+Optional properties:
+
+- VDDD-supply : the regulator provider of VDDD
+
 Example:
 
 codec: sgtl5000@0a {
 	compatible = "fsl,sgtl5000";
 	reg = <0x0a>;
 	clocks = <&clks 150>;
+	VDDA-supply = <&reg_3p3v>;
+	VDDIO-supply = <&reg_3p3v>;
 };

Documentation/devicetree/bindings/thermal/imx-thermal.txt

@@ -1,7 +1,10 @@
 * Temperature Monitor (TEMPMON) on Freescale i.MX SoCs
 
 Required properties:
-- compatible : "fsl,imx6q-thermal"
+- compatible : "fsl,imx6q-tempmon" for i.MX6Q, "fsl,imx6sx-tempmon" for i.MX6SX.
+  i.MX6SX has two more IRQs than i.MX6Q, one is IRQ_LOW and the other is IRQ_PANIC,
+  when temperature is below than low threshold, IRQ_LOW will be triggered, when temperature
+  is higher than panic threshold, system will auto reboot by SRC module.
 - fsl,tempmon : phandle pointer to system controller that contains TEMPMON
   control registers, e.g. ANATOP on imx6q.
 - fsl,tempmon-data : phandle pointer to fuse controller that contains TEMPMON

Documentation/devicetree/bindings/watchdog/cadence-wdt.txt

@@ -0,0 +1,24 @@
+Zynq Watchdog Device Tree Bindings
+-------------------------------------------
+
+Required properties:
+- compatible		: Should be "cdns,wdt-r1p2".
+- clocks		: This is pclk (APB clock).
+- interrupts		: This is wd_irq - watchdog timeout interrupt.
+- interrupt-parent	: Must be core interrupt controller.
+
+Optional properties
+- reset-on-timeout	: If this property exists, then a reset is done
+			  when watchdog times out.
+- timeout-sec		: Watchdog timeout value (in seconds).
+
+Example:
+	watchdog@f8005000 {
+		compatible = "cdns,wdt-r1p2";
+		clocks = <&clkc 45>;
+		interrupt-parent = <&intc>;
+		interrupts = <0 9 1>;
+		reg = <0xf8005000 0x1000>;
+		reset-on-timeout;
+		timeout-sec = <10>;
+	};

Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt

@@ -7,7 +7,8 @@ Required properties:
 
 Optional property:
 - big-endian: If present the watchdog device's registers are implemented
-  in big endian mode, otherwise in little mode.
+  in big endian mode, otherwise in native mode(same with CPU), for more
+  detail please see: Documentation/devicetree/bindings/regmap/regmap.txt.
 
 Examples:
 

Documentation/devicetree/bindings/watchdog/meson6-wdt.txt

@@ -0,0 +1,13 @@
+Meson SoCs Watchdog timer
+
+Required properties:
+
+- compatible : should be "amlogic,meson6-wdt"
+- reg : Specifies base physical address and size of the registers.
+
+Example:
+
+wdt: watchdog@c1109900 {
+	compatible = "amlogic,meson6-wdt";
+	reg = <0xc1109900 0x8>;
+};

Documentation/devicetree/bindings/watchdog/qcom-wdt.txt

@@ -0,0 +1,24 @@
+Qualcomm Krait Processor Sub-system (KPSS) Watchdog
+---------------------------------------------------
+
+Required properties :
+- compatible : shall contain only one of the following:
+
+			"qcom,kpss-wdt-msm8960"
+			"qcom,kpss-wdt-apq8064"
+			"qcom,kpss-wdt-ipq8064"
+
+- reg : shall contain base register location and length
+- clocks : shall contain the input clock
+
+Optional properties :
+- timeout-sec : shall contain the default watchdog timeout in seconds,
+                if unset, the default timeout is 30 seconds
+
+Example:
+	watchdog@208a038 {
+		compatible = "qcom,kpss-wdt-ipq8064";
+		reg = <0x0208a038 0x40>;
+		clocks = <&sleep_clk>;
+		timeout-sec = <10>;
+	};

Documentation/devicetree/bindings/watchdog/samsung-wdt.txt

@@ -9,6 +9,7 @@ Required properties:
 	(a) "samsung,s3c2410-wdt" for Exynos4 and previous SoCs
 	(b) "samsung,exynos5250-wdt" for Exynos5250
 	(c) "samsung,exynos5420-wdt" for Exynos5420
+	(c) "samsung,exynos7-wdt" for Exynos7
 
 - reg : base physical address of the controller and length of memory mapped
 	region.

Documentation/filesystems/Locking

@@ -67,6 +67,7 @@ prototypes:
 				struct file *, unsigned open_flag,
 				umode_t create_mode, int *opened);
 	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+	int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
 
 locking rules:
 	all may block
@@ -96,6 +97,7 @@ fiemap:		no
 update_time:	no
 atomic_open:	yes
 tmpfile:	no
+dentry_open:	no
 
 	Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
 victim.

Documentation/filesystems/overlayfs.txt

@@ -0,0 +1,198 @@
+Written by: Neil Brown <neilb@suse.de>
+
+Overlay Filesystem
+==================
+
+This document describes a prototype for a new approach to providing
+overlay-filesystem functionality in Linux (sometimes referred to as
+union-filesystems).  An overlay-filesystem tries to present a
+filesystem which is the result over overlaying one filesystem on top
+of the other.
+
+The result will inevitably fail to look exactly like a normal
+filesystem for various technical reasons.  The expectation is that
+many use cases will be able to ignore these differences.
+
+This approach is 'hybrid' because the objects that appear in the
+filesystem do not all appear to belong to that filesystem.  In many
+cases an object accessed in the union will be indistinguishable
+from accessing the corresponding object from the original filesystem.
+This is most obvious from the 'st_dev' field returned by stat(2).
+
+While directories will report an st_dev from the overlay-filesystem,
+all non-directory objects will report an st_dev from the lower or
+upper filesystem that is providing the object.  Similarly st_ino will
+only be unique when combined with st_dev, and both of these can change
+over the lifetime of a non-directory object.  Many applications and
+tools ignore these values and will not be affected.
+
+Upper and Lower
+---------------
+
+An overlay filesystem combines two filesystems - an 'upper' filesystem
+and a 'lower' filesystem.  When a name exists in both filesystems, the
+object in the 'upper' filesystem is visible while the object in the
+'lower' filesystem is either hidden or, in the case of directories,
+merged with the 'upper' object.
+
+It would be more correct to refer to an upper and lower 'directory
+tree' rather than 'filesystem' as it is quite possible for both
+directory trees to be in the same filesystem and there is no
+requirement that the root of a filesystem be given for either upper or
+lower.
+
+The lower filesystem can be any filesystem supported by Linux and does
+not need to be writable.  The lower filesystem can even be another
+overlayfs.  The upper filesystem will normally be writable and if it
+is it must support the creation of trusted.* extended attributes, and
+must provide valid d_type in readdir responses, so NFS is not suitable.
+
+A read-only overlay of two read-only filesystems may use any
+filesystem type.
+
+Directories
+-----------
+
+Overlaying mainly involves directories.  If a given name appears in both
+upper and lower filesystems and refers to a non-directory in either,
+then the lower object is hidden - the name refers only to the upper
+object.
+
+Where both upper and lower objects are directories, a merged directory
+is formed.
+
+At mount time, the two directories given as mount options "lowerdir" and
+"upperdir" are combined into a merged directory:
+
+  mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper,\
+workdir=/work /merged
+
+The "workdir" needs to be an empty directory on the same filesystem
+as upperdir.
+
+Then whenever a lookup is requested in such a merged directory, the
+lookup is performed in each actual directory and the combined result
+is cached in the dentry belonging to the overlay filesystem.  If both
+actual lookups find directories, both are stored and a merged
+directory is created, otherwise only one is stored: the upper if it
+exists, else the lower.
+
+Only the lists of names from directories are merged.  Other content
+such as metadata and extended attributes are reported for the upper
+directory only.  These attributes of the lower directory are hidden.
+
+whiteouts and opaque directories
+--------------------------------
+
+In order to support rm and rmdir without changing the lower
+filesystem, an overlay filesystem needs to record in the upper filesystem
+that files have been removed.  This is done using whiteouts and opaque
+directories (non-directories are always opaque).
+
+A whiteout is created as a character device with 0/0 device number.
+When a whiteout is found in the upper level of a merged directory, any
+matching name in the lower level is ignored, and the whiteout itself
+is also hidden.
+
+A directory is made opaque by setting the xattr "trusted.overlay.opaque"
+to "y".  Where the upper filesystem contains an opaque directory, any
+directory in the lower filesystem with the same name is ignored.
+
+readdir
+-------
+
+When a 'readdir' request is made on a merged directory, the upper and
+lower directories are each read and the name lists merged in the
+obvious way (upper is read first, then lower - entries that already
+exist are not re-added).  This merged name list is cached in the
+'struct file' and so remains as long as the file is kept open.  If the
+directory is opened and read by two processes at the same time, they
+will each have separate caches.  A seekdir to the start of the
+directory (offset 0) followed by a readdir will cause the cache to be
+discarded and rebuilt.
+
+This means that changes to the merged directory do not appear while a
+directory is being read.  This is unlikely to be noticed by many
+programs.
+
+seek offsets are assigned sequentially when the directories are read.
+Thus if
+  - read part of a directory
+  - remember an offset, and close the directory
+  - re-open the directory some time later
+  - seek to the remembered offset
+
+there may be little correlation between the old and new locations in
+the list of filenames, particularly if anything has changed in the
+directory.
+
+Readdir on directories that are not merged is simply handled by the
+underlying directory (upper or lower).
+
+
+Non-directories
+---------------
+
+Objects that are not directories (files, symlinks, device-special
+files etc.) are presented either from the upper or lower filesystem as
+appropriate.  When a file in the lower filesystem is accessed in a way
+the requires write-access, such as opening for write access, changing
+some metadata etc., the file is first copied from the lower filesystem
+to the upper filesystem (copy_up).  Note that creating a hard-link
+also requires copy_up, though of course creation of a symlink does
+not.
+
+The copy_up may turn out to be unnecessary, for example if the file is
+opened for read-write but the data is not modified.
+
+The copy_up process first makes sure that the containing directory
+exists in the upper filesystem - creating it and any parents as
+necessary.  It then creates the object with the same metadata (owner,
+mode, mtime, symlink-target etc.) and then if the object is a file, the
+data is copied from the lower to the upper filesystem.  Finally any
+extended attributes are copied up.
+
+Once the copy_up is complete, the overlay filesystem simply
+provides direct access to the newly created file in the upper
+filesystem - future operations on the file are barely noticed by the
+overlay filesystem (though an operation on the name of the file such as
+rename or unlink will of course be noticed and handled).
+
+
+Non-standard behavior
+---------------------
+
+The copy_up operation essentially creates a new, identical file and
+moves it over to the old name.  The new file may be on a different
+filesystem, so both st_dev and st_ino of the file may change.
+
+Any open files referring to this inode will access the old data and
+metadata.  Similarly any file locks obtained before copy_up will not
+apply to the copied up file.
+
+On a file opened with O_RDONLY fchmod(2), fchown(2), futimesat(2) and
+fsetxattr(2) will fail with EROFS.
+
+If a file with multiple hard links is copied up, then this will
+"break" the link.  Changes will not be propagated to other names
+referring to the same inode.
+
+Symlinks in /proc/PID/ and /proc/PID/fd which point to a non-directory
+object in overlayfs will not contain valid absolute paths, only
+relative paths leading up to the filesystem's root.  This will be
+fixed in the future.
+
+Some operations are not atomic, for example a crash during copy_up or
+rename will leave the filesystem in an inconsistent state.  This will
+be addressed in the future.
+
+Changes to underlying filesystems
+---------------------------------
+
+Offline changes, when the overlay is not mounted, are allowed to either
+the upper or the lower trees.
+
+Changes to the underlying filesystems while part of a mounted overlay
+filesystem are not allowed.  If the underlying filesystem is changed,
+the behavior of the overlay is undefined, though it will not result in
+a crash or deadlock.

Documentation/filesystems/vfs.txt

@@ -364,6 +364,7 @@ struct inode_operations {
 	int (*atomic_open)(struct inode *, struct dentry *, struct file *,
 			unsigned open_flag, umode_t create_mode, int *opened);
 	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+	int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
 };
 
 Again, all methods are called without any locks being held, unless
@@ -696,6 +697,12 @@ struct address_space_operations {
   	but instead uses bmap to find out where the blocks in the file
   	are and uses those addresses directly.
 
+  dentry_open: *WARNING: probably going away soon, do not use!* This is an
+	alternative to f_op->open(), the difference is that this method may open
+	a file not necessarily originating from the same filesystem as the one
+	i_op->open() was called on.  It may be useful for stacking filesystems
+	which want to allow native I/O directly on underlying files.
+
 
   invalidatepage: If a page has PagePrivate set, then invalidatepage
         will be called when part or all of the page is to be removed

Documentation/kernel-parameters.txt

@@ -1015,10 +1015,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Format: {"off" | "on" | "skip[mbr]"}
 
 	efi=		[EFI]
-			Format: { "old_map" }
+			Format: { "old_map", "nochunk", "noruntime" }
 			old_map [X86-64]: switch to the old ioremap-based EFI
 			runtime services mapping. 32-bit still uses this one by
 			default.
+			nochunk: disable reading files in "chunks" in the EFI
+			boot stub, as chunking can cause problems with some
+			firmware implementations.
+			noruntime : disable EFI runtime services support
 
 	efi_no_storage_paranoia [EFI; X86]
 			Using this parameter you can use more than 50% of
@@ -2232,7 +2236,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	nodsp		[SH] Disable hardware DSP at boot time.
 
-	noefi		[X86] Disable EFI runtime services support.
+	noefi		Disable EFI runtime services support.
 
 	noexec		[IA-64]
 
@@ -3465,6 +3469,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			e.g. base its process migration decisions on it.
 			Default is on.
 
+	topology_updates= [KNL, PPC, NUMA]
+			Format: {off}
+			Specify if the kernel should ignore (off)
+			topology updates sent by the hypervisor to this
+			LPAR.
+
 	tp720=		[HW,PS2]
 
 	tpm_suspend_pcr=[HW,TPM]

Documentation/mailbox.txt

@@ -0,0 +1,122 @@
+		The Common Mailbox Framework
+		Jassi Brar <jaswinder.singh@linaro.org>
+
+ This document aims to help developers write client and controller
+drivers for the API. But before we start, let us note that the
+client (especially) and controller drivers are likely going to be
+very platform specific because the remote firmware is likely to be
+proprietary and implement non-standard protocol. So even if two
+platforms employ, say, PL320 controller, the client drivers can't
+be shared across them. Even the PL320 driver might need to accommodate
+some platform specific quirks. So the API is meant mainly to avoid
+similar copies of code written for each platform. Having said that,
+nothing prevents the remote f/w to also be Linux based and use the
+same api there. However none of that helps us locally because we only
+ever deal at client's protocol level.
+ Some of the choices made during implementation are the result of this
+peculiarity of this "common" framework.
+
+
+
+	Part 1 - Controller Driver (See include/linux/mailbox_controller.h)
+
+ Allocate mbox_controller and the array of mbox_chan.
+Populate mbox_chan_ops, except peek_data() all are mandatory.
+The controller driver might know a message has been consumed
+by the remote by getting an IRQ or polling some hardware flag
+or it can never know (the client knows by way of the protocol).
+The method in order of preference is IRQ -> Poll -> None, which
+the controller driver should set via 'txdone_irq' or 'txdone_poll'
+or neither.
+
+
+	Part 2 - Client Driver (See include/linux/mailbox_client.h)
+
+ The client might want to operate in blocking mode (synchronously
+send a message through before returning) or non-blocking/async mode (submit
+a message and a callback function to the API and return immediately).
+
+
+struct demo_client {
+	struct mbox_client cl;
+	struct mbox_chan *mbox;
+	struct completion c;
+	bool async;
+	/* ... */
+};
+
+/*
+ * This is the handler for data received from remote. The behaviour is purely
+ * dependent upon the protocol. This is just an example.
+ */
+static void message_from_remote(struct mbox_client *cl, void *mssg)
+{
+	struct demo_client *dc = container_of(mbox_client,
+						struct demo_client, cl);
+	if (dc->aysnc) {
+		if (is_an_ack(mssg)) {
+			/* An ACK to our last sample sent */
+			return; /* Or do something else here */
+		} else { /* A new message from remote */
+			queue_req(mssg);
+		}
+	} else {
+		/* Remote f/w sends only ACK packets on this channel */
+		return;
+	}
+}
+
+static void sample_sent(struct mbox_client *cl, void *mssg, int r)
+{
+	struct demo_client *dc = container_of(mbox_client,
+						struct demo_client, cl);
+	complete(&dc->c);
+}
+
+static void client_demo(struct platform_device *pdev)
+{
+	struct demo_client *dc_sync, *dc_async;
+	/* The controller already knows async_pkt and sync_pkt */
+	struct async_pkt ap;
+	struct sync_pkt sp;
+
+	dc_sync = kzalloc(sizeof(*dc_sync), GFP_KERNEL);
+	dc_async = kzalloc(sizeof(*dc_async), GFP_KERNEL);
+
+	/* Populate non-blocking mode client */
+	dc_async->cl.dev = &pdev->dev;
+	dc_async->cl.rx_callback = message_from_remote;
+	dc_async->cl.tx_done = sample_sent;
+	dc_async->cl.tx_block = false;
+	dc_async->cl.tx_tout = 0; /* doesn't matter here */
+	dc_async->cl.knows_txdone = false; /* depending upon protocol */
+	dc_async->async = true;
+	init_completion(&dc_async->c);
+
+	/* Populate blocking mode client */
+	dc_sync->cl.dev = &pdev->dev;
+	dc_sync->cl.rx_callback = message_from_remote;
+	dc_sync->cl.tx_done = NULL; /* operate in blocking mode */
+	dc_sync->cl.tx_block = true;
+	dc_sync->cl.tx_tout = 500; /* by half a second */
+	dc_sync->cl.knows_txdone = false; /* depending upon protocol */
+	dc_sync->async = false;
+
+	/* ASync mailbox is listed second in 'mboxes' property */
+	dc_async->mbox = mbox_request_channel(&dc_async->cl, 1);
+	/* Populate data packet */
+	/* ap.xxx = 123; etc */
+	/* Send async message to remote */
+	mbox_send_message(dc_async->mbox, &ap);
+
+	/* Sync mailbox is listed first in 'mboxes' property */
+	dc_sync->mbox = mbox_request_channel(&dc_sync->cl, 0);
+	/* Populate data packet */
+	/* sp.abc = 123; etc */
+	/* Send message to remote in blocking mode */
+	mbox_send_message(dc_sync->mbox, &sp);
+	/* At this point 'sp' has been sent */
+
+	/* Now wait for async chan to be done */
+	wait_for_completion(&dc_async->c);
+}

Documentation/power/pm_qos_interface.txt

@@ -5,7 +5,8 @@ performance expectations by drivers, subsystems and user space applications on
 one of the parameters.
 
 Two different PM QoS frameworks are available:
-1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput.
+1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput,
+memory_bandwidth.
 2. the per-device PM QoS framework provides the API to manage the per-device latency
 constraints and PM QoS flags.
 
@@ -13,6 +14,7 @@ Each parameters have defined units:
  * latency: usec
  * timeout: usec
  * throughput: kbs (kilo bit / sec)
+ * memory bandwidth: mbs (mega bit / sec)
 
 
 1. PM QoS framework

Documentation/scsi/osd.txt

@@ -184,8 +184,7 @@ Any problems, questions, bug reports, lonely OSD nights, please email:
 More up-to-date information can be found on:
 http://open-osd.org
 
-Boaz Harrosh <bharrosh@panasas.com>
-Benny Halevy <bhalevy@panasas.com>
+Boaz Harrosh <ooo@electrozaur.com>
 
 References
 ==========

Documentation/target/tcmu-design.txt

@@ -0,0 +1,378 @@
+Contents:
+
+1) TCM Userspace Design
+  a) Background
+  b) Benefits
+  c) Design constraints
+  d) Implementation overview
+     i. Mailbox
+     ii. Command ring
+     iii. Data Area
+  e) Device discovery
+  f) Device events
+  g) Other contingencies
+2) Writing a user pass-through handler
+  a) Discovering and configuring TCMU uio devices
+  b) Waiting for events on the device(s)
+  c) Managing the command ring
+3) Command filtering and pass_level
+4) A final note
+
+
+TCM Userspace Design
+--------------------
+
+TCM is another name for LIO, an in-kernel iSCSI target (server).
+Existing TCM targets run in the kernel.  TCMU (TCM in Userspace)
+allows userspace programs to be written which act as iSCSI targets.
+This document describes the design.
+
+The existing kernel provides modules for different SCSI transport
+protocols.  TCM also modularizes the data storage.  There are existing
+modules for file, block device, RAM or using another SCSI device as
+storage.  These are called "backstores" or "storage engines".  These
+built-in modules are implemented entirely as kernel code.
+
+Background:
+
+In addition to modularizing the transport protocol used for carrying
+SCSI commands ("fabrics"), the Linux kernel target, LIO, also modularizes
+the actual data storage as well. These are referred to as "backstores"
+or "storage engines". The target comes with backstores that allow a
+file, a block device, RAM, or another SCSI device to be used for the
+local storage needed for the exported SCSI LUN. Like the rest of LIO,
+these are implemented entirely as kernel code.
+
+These backstores cover the most common use cases, but not all. One new
+use case that other non-kernel target solutions, such as tgt, are able
+to support is using Gluster's GLFS or Ceph's RBD as a backstore. The
+target then serves as a translator, allowing initiators to store data
+in these non-traditional networked storage systems, while still only
+using standard protocols themselves.
+
+If the target is a userspace process, supporting these is easy. tgt,
+for example, needs only a small adapter module for each, because the
+modules just use the available userspace libraries for RBD and GLFS.
+
+Adding support for these backstores in LIO is considerably more
+difficult, because LIO is entirely kernel code. Instead of undertaking
+the significant work to port the GLFS or RBD APIs and protocols to the
+kernel, another approach is to create a userspace pass-through
+backstore for LIO, "TCMU".
+
+
+Benefits:
+
+In addition to allowing relatively easy support for RBD and GLFS, TCMU
+will also allow easier development of new backstores. TCMU combines
+with the LIO loopback fabric to become something similar to FUSE
+(Filesystem in Userspace), but at the SCSI layer instead of the
+filesystem layer. A SUSE, if you will.
+
+The disadvantage is there are more distinct components to configure, and
+potentially to malfunction. This is unavoidable, but hopefully not
+fatal if we're careful to keep things as simple as possible.
+
+Design constraints:
+
+- Good performance: high throughput, low latency
+- Cleanly handle if userspace:
+   1) never attaches
+   2) hangs
+   3) dies
+   4) misbehaves
+- Allow future flexibility in user & kernel implementations
+- Be reasonably memory-efficient
+- Simple to configure & run
+- Simple to write a userspace backend
+
+
+Implementation overview:
+
+The core of the TCMU interface is a memory region that is shared
+between kernel and userspace. Within this region is: a control area
+(mailbox); a lockless producer/consumer circular buffer for commands
+to be passed up, and status returned; and an in/out data buffer area.
+
+TCMU uses the pre-existing UIO subsystem. UIO allows device driver
+development in userspace, and this is conceptually very close to the
+TCMU use case, except instead of a physical device, TCMU implements a
+memory-mapped layout designed for SCSI commands. Using UIO also
+benefits TCMU by handling device introspection (e.g. a way for
+userspace to determine how large the shared region is) and signaling
+mechanisms in both directions.
+
+There are no embedded pointers in the memory region. Everything is
+expressed as an offset from the region's starting address. This allows
+the ring to still work if the user process dies and is restarted with
+the region mapped at a different virtual address.
+
+See target_core_user.h for the struct definitions.
+
+The Mailbox:
+
+The mailbox is always at the start of the shared memory region, and
+contains a version, details about the starting offset and size of the
+command ring, and head and tail pointers to be used by the kernel and
+userspace (respectively) to put commands on the ring, and indicate
+when the commands are completed.
+
+version - 1 (userspace should abort if otherwise)
+flags - none yet defined.
+cmdr_off - The offset of the start of the command ring from the start
+of the memory region, to account for the mailbox size.
+cmdr_size - The size of the command ring. This does *not* need to be a
+power of two.
+cmd_head - Modified by the kernel to indicate when a command has been
+placed on the ring.
+cmd_tail - Modified by userspace to indicate when it has completed
+processing of a command.
+
+The Command Ring:
+
+Commands are placed on the ring by the kernel incrementing
+mailbox.cmd_head by the size of the command, modulo cmdr_size, and
+then signaling userspace via uio_event_notify(). Once the command is
+completed, userspace updates mailbox.cmd_tail in the same way and
+signals the kernel via a 4-byte write(). When cmd_head equals
+cmd_tail, the ring is empty -- no commands are currently waiting to be
+processed by userspace.
+
+TCMU commands start with a common header containing "len_op", a 32-bit
+value that stores the length, as well as the opcode in the lowest
+unused bits. Currently only two opcodes are defined, TCMU_OP_PAD and
+TCMU_OP_CMD. When userspace encounters a command with PAD opcode, it
+should skip ahead by the bytes in "length". (The kernel inserts PAD
+entries to ensure each CMD entry fits contigously into the circular
+buffer.)
+
+When userspace handles a CMD, it finds the SCSI CDB (Command Data
+Block) via tcmu_cmd_entry.req.cdb_off. This is an offset from the
+start of the overall shared memory region, not the entry. The data
+in/out buffers are accessible via tht req.iov[] array. Note that
+each iov.iov_base is also an offset from the start of the region.
+
+TCMU currently does not support BIDI operations.
+
+When completing a command, userspace sets rsp.scsi_status, and
+rsp.sense_buffer if necessary. Userspace then increments
+mailbox.cmd_tail by entry.hdr.length (mod cmdr_size) and signals the
+kernel via the UIO method, a 4-byte write to the file descriptor.
+
+The Data Area:
+
+This is shared-memory space after the command ring. The organization
+of this area is not defined in the TCMU interface, and userspace
+should access only the parts referenced by pending iovs.
+
+
+Device Discovery:
+
+Other devices may be using UIO besides TCMU. Unrelated user processes
+may also be handling different sets of TCMU devices. TCMU userspace
+processes must find their devices by scanning sysfs
+class/uio/uio*/name. For TCMU devices, these names will be of the
+format:
+
+tcm-user/<hba_num>/<device_name>/<subtype>/<path>
+
+where "tcm-user" is common for all TCMU-backed UIO devices. <hba_num>
+and <device_name> allow userspace to find the device's path in the
+kernel target's configfs tree. Assuming the usual mount point, it is
+found at:
+
+/sys/kernel/config/target/core/user_<hba_num>/<device_name>
+
+This location contains attributes such as "hw_block_size", that
+userspace needs to know for correct operation.
+
+<subtype> will be a userspace-process-unique string to identify the
+TCMU device as expecting to be backed by a certain handler, and <path>
+will be an additional handler-specific string for the user process to
+configure the device, if needed. The name cannot contain ':', due to
+LIO limitations.
+
+For all devices so discovered, the user handler opens /dev/uioX and
+calls mmap():
+
+mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)
+
+where size must be equal to the value read from
+/sys/class/uio/uioX/maps/map0/size.
+
+
+Device Events:
+
+If a new device is added or removed, a notification will be broadcast
+over netlink, using a generic netlink family name of "TCM-USER" and a
+multicast group named "config". This will include the UIO name as
+described in the previous section, as well as the UIO minor
+number. This should allow userspace to identify both the UIO device and
+the LIO device, so that after determining the device is supported
+(based on subtype) it can take the appropriate action.
+
+
+Other contingencies:
+
+Userspace handler process never attaches:
+
+- TCMU will post commands, and then abort them after a timeout period
+  (30 seconds.)
+
+Userspace handler process is killed:
+
+- It is still possible to restart and re-connect to TCMU
+  devices. Command ring is preserved. However, after the timeout period,
+  the kernel will abort pending tasks.
+
+Userspace handler process hangs:
+
+- The kernel will abort pending tasks after a timeout period.
+
+Userspace handler process is malicious:
+
+- The process can trivially break the handling of devices it controls,
+  but should not be able to access kernel memory outside its shared
+  memory areas.
+
+
+Writing a user pass-through handler (with example code)
+-------------------------------------------------------
+
+A user process handing a TCMU device must support the following:
+
+a) Discovering and configuring TCMU uio devices
+b) Waiting for events on the device(s)
+c) Managing the command ring: Parsing operations and commands,
+   performing work as needed, setting response fields (scsi_status and
+   possibly sense_buffer), updating cmd_tail, and notifying the kernel
+   that work has been finished
+
+First, consider instead writing a plugin for tcmu-runner. tcmu-runner
+implements all of this, and provides a higher-level API for plugin
+authors.
+
+TCMU is designed so that multiple unrelated processes can manage TCMU
+devices separately. All handlers should make sure to only open their
+devices, based opon a known subtype string.
+
+a) Discovering and configuring TCMU UIO devices:
+
+(error checking omitted for brevity)
+
+int fd, dev_fd;
+char buf[256];
+unsigned long long map_len;
+void *map;
+
+fd = open("/sys/class/uio/uio0/name", O_RDONLY);
+ret = read(fd, buf, sizeof(buf));
+close(fd);
+buf[ret-1] = '\0'; /* null-terminate and chop off the \n */
+
+/* we only want uio devices whose name is a format we expect */
+if (strncmp(buf, "tcm-user", 8))
+	exit(-1);
+
+/* Further checking for subtype also needed here */
+
+fd = open(/sys/class/uio/%s/maps/map0/size, O_RDONLY);
+ret = read(fd, buf, sizeof(buf));
+close(fd);
+str_buf[ret-1] = '\0'; /* null-terminate and chop off the \n */
+
+map_len = strtoull(buf, NULL, 0);
+
+dev_fd = open("/dev/uio0", O_RDWR);
+map = mmap(NULL, map_len, PROT_READ|PROT_WRITE, MAP_SHARED, dev_fd, 0);
+
+
+b) Waiting for events on the device(s)
+
+while (1) {
+  char buf[4];
+
+  int ret = read(dev_fd, buf, 4); /* will block */
+
+  handle_device_events(dev_fd, map);
+}
+
+
+c) Managing the command ring
+
+#include <linux/target_core_user.h>
+
+int handle_device_events(int fd, void *map)
+{
+  struct tcmu_mailbox *mb = map;
+  struct tcmu_cmd_entry *ent = (void *) mb + mb->cmdr_off + mb->cmd_tail;
+  int did_some_work = 0;
+
+  /* Process events from cmd ring until we catch up with cmd_head */
+  while (ent != (void *)mb + mb->cmdr_off + mb->cmd_head) {
+
+    if (tcmu_hdr_get_op(&ent->hdr) == TCMU_OP_CMD) {
+      uint8_t *cdb = (void *)mb + ent->req.cdb_off;
+      bool success = true;
+
+      /* Handle command here. */
+      printf("SCSI opcode: 0x%x\n", cdb[0]);
+
+      /* Set response fields */
+      if (success)
+        ent->rsp.scsi_status = SCSI_NO_SENSE;
+      else {
+        /* Also fill in rsp->sense_buffer here */
+        ent->rsp.scsi_status = SCSI_CHECK_CONDITION;
+      }
+    }
+    else {
+      /* Do nothing for PAD entries */
+    }
+
+    /* update cmd_tail */
+    mb->cmd_tail = (mb->cmd_tail + tcmu_hdr_get_len(&ent->hdr)) % mb->cmdr_size;
+    ent = (void *) mb + mb->cmdr_off + mb->cmd_tail;
+    did_some_work = 1;
+  }
+
+  /* Notify the kernel that work has been finished */
+  if (did_some_work) {
+    uint32_t buf = 0;
+
+    write(fd, &buf, 4);
+  }
+
+  return 0;
+}
+
+
+Command filtering and pass_level
+--------------------------------
+
+TCMU supports a "pass_level" option with valid values of 0 or 1.  When
+the value is 0 (the default), nearly all SCSI commands received for
+the device are passed through to the handler. This allows maximum
+flexibility but increases the amount of code required by the handler,
+to support all mandatory SCSI commands. If pass_level is set to 1,
+then only IO-related commands are presented, and the rest are handled
+by LIO's in-kernel command emulation. The commands presented at level
+1 include all versions of:
+
+READ
+WRITE
+WRITE_VERIFY
+XDWRITEREAD
+WRITE_SAME
+COMPARE_AND_WRITE
+SYNCHRONIZE_CACHE
+UNMAP
+
+
+A final note
+------------
+
+Please be careful to return codes as defined by the SCSI
+specifications. These are different than some values defined in the
+scsi/scsi.h include file. For example, CHECK CONDITION's status code
+is 2, not 1.

MAINTAINERS

@@ -1749,6 +1749,13 @@ M:	Nicolas Ferre <nicolas.ferre@atmel.com>
 S:	Supported
 F:	drivers/spi/spi-atmel.*
 
+ATMEL SSC DRIVER
+M:	Bo Shen <voice.shen@atmel.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Supported
+F:	drivers/misc/atmel-ssc.c
+F:	include/linux/atmel-ssc.h
+
 ATMEL Timer Counter (TC) AND CLOCKSOURCE DRIVERS
 M:	Nicolas Ferre <nicolas.ferre@atmel.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
@@ -5834,6 +5841,14 @@ S:	Maintained
 F:	drivers/net/macvlan.c
 F:	include/linux/if_macvlan.h
 
+MAILBOX API
+M:	Jassi Brar <jassisinghbrar@gmail.com>
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+F:	drivers/mailbox/
+F:	include/linux/mailbox_client.h
+F:	include/linux/mailbox_controller.h
+
 MAN-PAGES: MANUAL PAGES FOR LINUX -- Sections 2, 3, 4, 5, and 7
 M:	Michael Kerrisk <mtk.manpages@gmail.com>
 W:	http://www.kernel.org/doc/man-pages
@@ -6822,7 +6837,7 @@ S:	Orphan
 F:	drivers/net/wireless/orinoco/
 
 OSD LIBRARY and FILESYSTEM
-M:	Boaz Harrosh <bharrosh@panasas.com>
+M:	Boaz Harrosh <ooo@electrozaur.com>
 M:	Benny Halevy <bhalevy@primarydata.com>
 L:	osd-dev@open-osd.org
 W:	http://open-osd.org
@@ -6832,6 +6847,13 @@ F:	drivers/scsi/osd/
 F:	include/scsi/osd_*
 F:	fs/exofs/
 
+OVERLAYFS FILESYSTEM
+M:	Miklos Szeredi <miklos@szeredi.hu>
+L:	linux-fsdevel@vger.kernel.org
+S:	Supported
+F:	fs/overlayfs/*
+F:	Documentation/filesystems/overlayfs.txt
+
 P54 WIRELESS DRIVER
 M:	Christian Lamparter <chunkeey@googlemail.com>
 L:	linux-wireless@vger.kernel.org