This function is used by the block layer queue to bail out of
requests if the current request is towards an RPMB
"block device".

This was done to avoid boot time scanning of this "block
device" which was never really a block device, thus duct-taping
over the fact that it was badly engineered.

This problem is now gone as we removed the offending RPMB block
device in another patch and replaced it with a character
device.

Cc: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

In may, Steven sent a patch deleting the bounce buffer handling
and the CONFIG_MMC_BLOCK_BOUNCE option.

I chose the less invasive path of making it a runtime config
option, and we merged that successfully for kernel v4.12.

The code is however just standing in the way and taking up
space for seemingly no gain on any systems in wide use today.

Pierre says the code was there to improve speed on TI SDHCI
controllers on certain HP laptops and possibly some Ricoh
controllers as well. Early SDHCI controllers lacked the
scatter-gather feature, which made software bounce buffers
a significant speed boost.

We are clearly talking about the list of SDHCI PCI-based
MMC/SD card readers found in the pci_ids[] list in
drivers/mmc/host/sdhci-pci-core.c.

The TI SDHCI derivative is not supported by the upstream
kernel. This leaves the Ricoh.

What we can however notice is that the x86 defconfigs in the
kernel did not enable CONFIG_MMC_BLOCK_BOUNCE option, which
means that any such laptop would have to have a custom
configured kernel to actually take advantage of this
bounce buffer speed-up. It simply seems like there was
a speed optimization for the Ricoh controllers that noone
was using. (I have not checked the distro defconfigs but
I am pretty sure the situation is the same there.)

Bounce buffers increased performance on the OMAP HSMMC
at one point, and was part of the original submission in
commit a45c6cb8 ("[ARM] 5369/1: omap mmc: Add new
   omap hsmmc controller for 2430 and 34xx, v3")

This optimization was removed in
commit 0ccd76d4 ("omap_hsmmc: Implement scatter-gather
   emulation")
which found that scatter-gather emulation provided even
better performance.

The same was introduced for SDHCI in
commit 2134a922 ("sdhci: scatter-gather (ADMA) support")

I am pretty positively convinced that software
scatter-gather emulation will do for any host controller what
the bounce buffers were doing. Essentially, the bounce buffer
was a reimplementation of software scatter-gather-emulation in
the MMC subsystem, and it should be done away with.

Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Juha Yrjola <juha.yrjola@solidboot.com>
Cc: Steven J. Hill <Steven.Hill@cavium.com>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Suggested-by: NSteven J. Hill <Steven.Hill@cavium.com>
Suggested-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

mmc_init_request() depends on card->bouncesz so it must be calculated
before blk_init_allocated_queue() starts allocating requests.
Reported-by: NSeraphime Kirkovski <kirkseraph@gmail.com>
Fixes: 304419d8 ("mmc: core: Allocate per-request data using the..")
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Tested-by: NSeraphime Kirkovski <kirkseraph@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NPavel Machek <pavel@ucw.cz>

BLK_BOUNCE_ANY is the defauly now, so the call is superflous.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Just as we can use blk_mq_rq_from_pdu() to get the per-request
tag we can use blk_mq_rq_to_pdu() to get a request from a tag.
Introduce a static inline helper so we are on the clear what
is happening.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The mmc_queue_req is a per-request state container the MMC core uses
to carry bounce buffers, pointers to asynchronous requests and so on.
Currently allocated as a static array of objects, then as a request
comes in, a mmc_queue_req is assigned to it, and used during the
lifetime of the request.

This is backwards compared to how other block layer drivers work:
they usally let the block core provide a per-request struct that get
allocated right beind the struct request, and which can be obtained
using the blk_mq_rq_to_pdu() helper. (The _mq_ infix in this function
name is misleading: it is used by both the old and the MQ block
layer.)

The per-request struct gets allocated to the size stored in the queue
variable .cmd_size initialized using the .init_rq_fn() and
cleaned up using .exit_rq_fn().

The block layer code makes the MMC core rely on this mechanism to
allocate the per-request mmc_queue_req state container.

Doing this make a lot of complicated queue handling go away. We only
need to keep the .qnct that keeps count of how many request are
currently being processed by the MMC layer. The MQ block layer will
replace also this once we transition to it.

Doing this refactoring is necessary to move the ioctl() operations
into custom block layer requests tagged with REQ_OP_DRV_[IN|OUT]
instead of the custom code using the BigMMCHostLock that we have
today: those require that per-request data be obtainable easily from
a request after creating a custom request with e.g.:

struct request *rq = blk_get_request(q, REQ_OP_DRV_IN, __GFP_RECLAIM);
struct mmc_queue_req *mq_rq = req_to_mq_rq(rq);

And this is not possible with the current construction, as the request
is not immediately assigned the per-request state container, but
instead it gets assigned when the request finally enters the MMC
queue, which is way too late for custom requests.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
[Ulf: Folded in the fix to drop a call to blk_cleanup_queue()]
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NHeiner Kallweit <hkallweit1@gmail.com>

This option is activated by all multiplatform configs and what
not so we almost always have it turned on, and the memory it
saves is negligible, even more so moving forward. The actual
bounce buffer only gets allocated only when used, the only
thing the ifdefs are saving is a little bit of code.

It is highly improper to have this as a Kconfig option that
get turned on by Kconfig, make this a pure runtime-thing and
let the host decide whether we use bounce buffers. We add a
new property "disable_bounce" to the host struct.

Notice that mmc_queue_calc_bouncesz() already disables the
bounce buffers if host->max_segs != 1, so any arch that has a
maximum number of segments higher than 1 will have bounce
buffers disabled.

The option CONFIG_MMC_BLOCK_BOUNCE is default y so the
majority of platforms in the kernel already have it on, and
it then gets turned off at runtime since most of these have
a host->max_segs > 1. The few exceptions that have
host->max_segs == 1 and still turn off the bounce buffering
are those that disable it in their defconfig.

Those are the following:

arch/arm/configs/colibri_pxa300_defconfig
arch/arm/configs/zeus_defconfig
- Uses MMC_PXA, drivers/mmc/host/pxamci.c
- Sets host->max_segs = NR_SG, which is 1
- This needs its bounce buffer deactivated so we set
  host->disable_bounce to true in the host driver

arch/arm/configs/davinci_all_defconfig
- Uses MMC_DAVINCI, drivers/mmc/host/davinci_mmc.c
- This driver sets host->max_segs to MAX_NR_SG, which is 16
- That means this driver anyways disabled bounce buffers
- No special action needed for this platform

arch/arm/configs/lpc32xx_defconfig
arch/arm/configs/nhk8815_defconfig
arch/arm/configs/u300_defconfig
- Uses MMC_ARMMMCI, drivers/mmc/host/mmci.[c|h]
- This driver by default sets host->max_segs to NR_SG,
  which is 128, unless a DMA engine is used, and in that case
  the number of segments are also > 1
- That means this driver already disables bounce buffers
- No special action needed for these platforms

arch/arm/configs/sama5_defconfig
- Uses MMC_SDHCI, MMC_SDHCI_PLTFM, MMC_SDHCI_OF_AT91, MMC_ATMELMCI
- Uses drivers/mmc/host/sdhci.c
- Normally sets host->max_segs to SDHCI_MAX_SEGS which is 128 and
  thus disables bounce buffers
- Sets host->max_segs to 1 if SDHCI_USE_SDMA is set
- SDHCI_USE_SDMA is only set by SDHCI on PCI adapers
- That means that for this platform bounce buffers are already
  disabled at runtime
- No special action needed for this platform

arch/blackfin/configs/CM-BF533_defconfig
arch/blackfin/configs/CM-BF537E_defconfig
- Uses MMC_SPI (a simple MMC card connected on SPI pins)
- Uses drivers/mmc/host/mmc_spi.c
- Sets host->max_segs to MMC_SPI_BLOCKSATONCE which is 128
- That means this platform already disables bounce buffers at
  runtime
- No special action needed for these platforms

arch/mips/configs/cavium_octeon_defconfig
- Uses MMC_CAVIUM_OCTEON, drivers/mmc/host/cavium.c
- Sets host->max_segs to 16 or 1
- Setting host->disable_bounce to be sure for the 1 case

arch/mips/configs/qi_lb60_defconfig
- Uses MMC_JZ4740, drivers/mmc/host/jz4740_mmc.c
- This sets host->max_segs to 128 so bounce buffers are
  already runtime disabled
- No action needed for this platform

It would be interesting to come up with a list of the platforms
that actually end up using bounce buffers. I have not been
able to infer such a list, but it occurs when
host->max_segs == 1 and the bounce buffering is not explicitly
disabled.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Currently we use nornal Linux errno values in the block layer, and while
we accept any error a few have overloaded magic meanings.  This patch
instead introduces a new  blk_status_t value that holds block layer specific
status codes and explicitly explains their meaning.  Helpers to convert from
and to the previous special meanings are provided for now, but I suspect
we want to get rid of them in the long run - those drivers that have a
errno input (e.g. networking) usually get errnos that don't know about
the special block layer overloads, and similarly returning them to userspace
will usually return somethings that strictly speaking isn't correct
for file system operations, but that's left as an exercise for later.

For now the set of errors is a very limited set that closely corresponds
to the previous overloaded errno values, but there is some low hanging
fruite to improve it.

blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
typechecking, so that we can easily catch places passing the wrong values.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

eMMC can have multiple internal partitions that are represented as separate
disks / queues. However switching between partitions is only done when the
queue is empty. Consequently the array of mmc requests that are queued can
be shared between partitions saving memory.

Keep a pointer to the mmc request queue on the card, and use that instead
of allocating a new one for each partition.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Change from viewing the requests in progress as 'current' and 'previous',
to viewing them as a queue. The current request is allocated to the first
free slot. The presence of incomplete requests is determined from the
count (mq->qcnt) of entries in the queue. Non-read-write requests (i.e.
discards and flushes) are not added to the queue at all and require no
special handling. Also no special handling is needed for the
MMC_BLK_NEW_REQUEST case.

As well as allowing an arbitrarily sized queue, the queue thread function
is significantly simpler.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

mmc only supports discarding on large alignments, so the zeroing code
would always fall back to explicit writings of zeroes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Instead of masking and setting two bits in the "flags" field
for the mmc_queue, just use two bools named "suspended" and
"new_request".

The masking and setting would likely have race conditions
anyways, it is better to use a simple member like this.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

A significant amount of functions and other definitions are available
through the public mmc card.h header file. Let's slim down this public mmc
interface, as to prevent users from abusing it, by moving some of the
functions/definitions to private mmc header files.

This change concentrates on moving the functions into private mmc headers,
following changes may continue with additional clean-ups.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

A significant amount of functions are available through the public mmc
core.h header file. Let's slim down this public mmc interface, as to
prevent users from abusing it, by moving some of the functions to private
mmc header files.

This change concentrates on moving the functions into private mmc headers,
following changes may continue with additional clean-ups, as an example
some functions can be turned into static.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

* A multiplication for the size determination of a memory allocation
  indicated that an array data structure should be processed.
  Thus use the corresponding function "kmalloc_array".

  This issue was detected by using the Coccinelle software.

* Replace the specification of a data structure by a pointer dereference
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The block layer won't send requests the driver isn't asking for,
so remove this check.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Once upon a time it made sense to keep the mmc block device driver and its
related code, in its own directory called card. Over time, more an more
functions/structures have become shared through generic mmc header files,
between the core and the card directory. In other words, the relationship
between them has become closer.

By sharing functions/structures via generic header files, it becomes easy
for outside users to abuse them. In a way to avoid that from happen, let's
move the files from card directory into the core directory, as it enables
us to move definitions of functions/structures into mmc core specific
header files.

Note, this is only the first step in providing a cleaner mmc interface for
outside users. Following changes will do the actual cleanup, as that is not
part of this change.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

bounce_sg for mqrq_cur and mqrq_pre are proper
allocated when initializing the queue and will not
be freed before explicitly cleaning the queue. So from
the code itself it should be quite confident to remove
this check. If that BUG_ON take effects, it is mostly
likely the memory is randomly oopsing.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add a mmc_queue member to record the size of the queue, which currently
supports 2 requests on-the-go at a time. Instead of allocating resources
for 2 slots in the queue, allow for an arbitrary number.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

In preparation for supporting a queue of requests, factor out
mmc_queue_reqs_free_bufs().
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

In preparation for supporting a queue of requests, factor out
mmc_queue_alloc_sgs().
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

In preparation for supporting a queue of requests, factor out
mmc_queue_alloc_bounce_sgs().
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
[Ulf: Fixed compiler warning]
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

In preparation for supporting a queue of requests, factor out
mmc_queue_alloc_bounce_bufs().
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
[Ulf: Fixed compiler warning]
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The only time the driver sleeps expecting to be woken upon the arrival of
a new request, is when the dispatch queue is empty. The only time that it
is known whether the dispatch queue is empty is after NULL is returned
from blk_fetch_request() while under the queue lock.

Recognizing those facts, simplify the synchronization between the queue
thread and the request function. A couple of flags tell the request
function what to do, and the queue lock and barriers associated with
wake-ups ensure synchronization.

The result is simpler and allows the removal of the context_info lock.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

I've had it with this code now.

The packed command support is a complex hurdle in the MMC/SD block
layer, around 500+ lines of code which was introduced in 2013 in

commit ce39f9d1 ("mmc: support packed write command for eMMC4.5
devices")
commit abd9ac14 ("mmc: add packed command feature of eMMC4.5")

...and since then it has been rotting. The original author of the
code has disappeared from the community and the mail address is
bouncing.

For the code to be exercised the host must flag that it supports
packed commands, so in mmc_blk_prep_packed_list() which is called for
every single request, the following construction appears:

u8 max_packed_rw = 0;

if ((rq_data_dir(cur) == WRITE) &&
    mmc_host_packed_wr(card->host))
        max_packed_rw = card->ext_csd.max_packed_writes;

if (max_packed_rw == 0)
    goto no_packed;

This has the following logical deductions:

- Only WRITE commands can really be packed, so the solution is
  only half-done: we support packed WRITE but not packed READ.
  The packed command support has not been finalized by supporting
  reads in three years!

- mmc_host_packed_wr() is just a static inline that checks
  host->caps2 & MMC_CAP2_PACKED_WR. The problem with this is
  that NO upstream host sets this capability flag! No driver
  in the kernel is using it, and we can't test it. Packed
  command may be supported in out-of-tree code, but I doubt
  it. I doubt that the code is even working anymore due to
  other refactorings in the MMC block layer, who would
  notice if patches affecting it broke packed commands?
  No one.

- There is no Device Tree binding or code to mark a host as
  supporting packed read or write commands, just this flag
  in caps2, so for sure there are not any DT systems using
  it either.

It has other problems as well: mmc_blk_prep_packed_list() is
speculatively picking requests out of the request queue with
blk_fetch_request() making the MMC/SD stack harder to convert
to the multiqueue block layer. By this we get rid of an
obstacle.

The way I see it this is just cruft littering the MMC/SD
stack.

Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Maya Erez <qca_merez@qca.qualcomm.com>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

By moving the mmc_packed_init() and mmc_packed_clean() into the
only file in the kernel where they are used, we save two exported
functions and can staticize those to the block.c file.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.

This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests.  It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NShaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We have enough vtables in the kernel as it is, we don't need
this one to create even more artificial separation of concerns.

As is proved by the Makefile:

obj-$(CONFIG_MMC_BLOCK)         += mmc_block.o
mmc_block-objs                  := block.o queue.o

block.c and queue.c are baked into the same mmc_block.o object.
So why would one of these objects access a function in the
other object by dereferencing a pointer?

Create a new block.h header file for the single shared function
from block to queue and remove the function pointer and just
call the queue request function.

Apart from making the code more readable, this also makes link
optimizations possible and probably speeds up the call as well.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

We call mmc_req_is_special() after having processed a request, but
it could be freed after that. Check that ahead of time, and use
the cached value.
Reported-by: NHans de Goede <hdegoede@redhat.com>
Tested-by: NHans de Goede <hdegoede@redhat.com>
Fixes: c2df40df ("drivers: use req op accessor")
Signed-off-by: NJens Axboe <axboe@fb.com>

Commit 288dab8a ("block: add a separate operation type for secure
erase") split REQ_OP_SECURE_ERASE from REQ_OP_DISCARD without considering
all the places REQ_OP_DISCARD was being used to mean either. Fix those.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Fixes: 288dab8a ("block: add a separate operation type for secure erase")
Signed-off-by: NJens Axboe <axboe@fb.com>

Instead of overloading the discard support with the REQ_SECURE flag.
Use the opportunity to rename the queue flag as well, and remove the
dead checks for this flag in the RAID 1 and RAID 10 drivers that don't
claim support for secure erase.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NDan Williams <dan.j.williams@intel.com>
[hch: split from a larger patch by Dan]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Some drivers use it now, others just set the limits field manually.
But in preparation for splitting this into a hard and soft limit,
ensure that they all call the proper function for setting the hw
limit for discards.
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

On systems with CONFIG_PREEMPT=n, under certain circumstances, mmcqd
can continuously process requests for several seconds without blocking,
triggering the soft lockup watchdog.  For example, this can happen if
mmcqd runs on the CPU which services the controller's interrupt, and
a process on a different CPU continuously writes to the MMC block
device.

 NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [mmcqd/0:664]
 CPU: 0 PID: 664 Comm: mmcqd/0 Not tainted 4.1.0-rc7+ #4
 PC is at _raw_spin_unlock_irqrestore+0x24/0x28
 LR is at mmc_start_request+0x104/0x134
 ...
 [<805112a8>] (_raw_spin_unlock_irqrestore) from [<803db664>] (mmc_start_request+0x104/0x134)
 [<803db664>] (mmc_start_request) from [<803dc008>] (mmc_start_req+0x274/0x394)
 [<803dc008>] (mmc_start_req) from [<803eb2c4>] (mmc_blk_issue_rw_rq+0xd0/0xb98)
 [<803eb2c4>] (mmc_blk_issue_rw_rq) from [<803ebe8c>] (mmc_blk_issue_rq+0x100/0x470)
 [<803ebe8c>] (mmc_blk_issue_rq) from [<803ecab8>] (mmc_queue_thread+0xd0/0x170)
 [<803ecab8>] (mmc_queue_thread) from [<8003fd14>] (kthread+0xe0/0xfc)
 [<8003fd14>] (kthread) from [<8000f768>] (ret_from_fork+0x14/0x2c)

Fix it by adding a cond_resched() in the request handling loop so that
other processes get a chance to run.
Signed-off-by: NRabin Vincent <rabin.vincent@axis.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Use kernel.h macro definition.

Thanks to Julia Lawall for Coccinelle scripting support.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

During kernel boot, it will try to read some logical sectors
of each block device node for the possible partition table.

But since RPMB partition is special and can not be accessed
by normal eMMC read / write CMDs, it will cause below error
messages during kernel boot:
...
 mmc0: Got data interrupt 0x00000002 even though no data operation was in progress.
 mmcblk0rpmb: error -110 transferring data, sector 0, nr 32, cmd response 0x900, card status 0xb00
 mmcblk0rpmb: retrying using single block read
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900
 end_request: I/O error, dev mmcblk0rpmb, sector 0
 Buffer I/O error on device mmcblk0rpmb, logical block 0
 end_request: I/O error, dev mmcblk0rpmb, sector 8
 Buffer I/O error on device mmcblk0rpmb, logical block 1
 end_request: I/O error, dev mmcblk0rpmb, sector 16
 Buffer I/O error on device mmcblk0rpmb, logical block 2
 end_request: I/O error, dev mmcblk0rpmb, sector 24
 Buffer I/O error on device mmcblk0rpmb, logical block 3
...

This patch will discard the access request in eMMC queue if
it is RPMB partition access request. By this way, it avoids
trigger above error messages.

Fixes: 090d25fe ("mmc: core: Expose access to RPMB partition")
Signed-off-by: NYunpeng Gao <yunpeng.gao@intel.com>
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Tested-by: NMichael Shigorin <mike@altlinux.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Allocation of previous bounce buffer in mmc_init_queue when the current
bounce buffer allocation fails was leading to a crash later in
__blk_segment_map_sg. Error handling is improved by allocating previous
bounce buffer only if the current bounce buffer allocation succeeds.
Signed-off-by: NBhuvanesh Surachari <bhuvanesh_surachari@mentor.com>
Signed-off-by: NHarish Jenny K N <harish_kandiga@mentor.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.

Historically, all block devices have automatically made entropy
contributions.  But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
    - On SSD disks, the completion times aren't as random as they
      are for rotational drives. So it's questionable whether they
      should contribute to the random pool in the first place.
    - Calling add_disk_randomness() has a lot of overhead.

There are more reliable sources for randomness than non-rotational block
devices.  From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Use the much more common pr_warn instead of pr_warning.

Other miscellanea:

o Coalesce formats
o Realign arguments
o Remove extra spaces when coalescing formats
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>