block: move cache control settings out of queue->flags

Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features a

block: move cache control settings out of queue->flags

Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features and flags field for the driver set flags, and internal
(usually sysfs-controlled) flags in the block layer. Note that we'll
eventually remove enough field from queue_limits to bring it back to the
previous size.

The disable flag is inverted compared to the previous meaning, which
means it now survives a rescan, similar to the max_sectors and
max_discard_sectors user limits.

The FLUSH and FUA flags are now inherited by blk_stack_limits, which
simplified the code in dm a lot, but also causes a slight behavior
change in that dm-switch and dm-unstripe now advertise a write cache
despite setting num_flush_bios to 0. The I/O path will handle this
gracefully, but as far as I can tell the lack of num_flush_bios
and thus flush support is a pre-existing data integrity bug in those
targets that really needs fixing, after which a non-zero num_flush_bios
should be required in dm for targets that map to underlying devices.

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Ulf Hansson <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

mmc: switch to blk_mq_alloc_disk

Use the blk_mq_alloc_disk to allocate the request_queue and gendisk
together.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Ulf Hansson <ulf.hansson@li

mmc: switch to blk_mq_alloc_disk

Use the blk_mq_alloc_disk to allocate the request_queue and gendisk
together.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

mmc: core: Remove mq->use_cqe from the struct mmc_queue

The host->cqe_enabled is already containing the needed information about
whether the CQE is enabled or not, hence there is no need to keep ano

mmc: core: Remove mq->use_cqe from the struct mmc_queue

The host->cqe_enabled is already containing the needed information about
whether the CQE is enabled or not, hence there is no need to keep another
copy of it around.

Signed-off-by: Luca Porzio <[email protected]>
Signed-off-by: Zhan Liu <[email protected]>
Link: https://lore.kernel.org/r/20210215003217.GA12240@lupo-laptop
Signed-off-by: Ulf Hansson <[email protected]>

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mmc: queue: Remove unused define

MMC_CQE_QUEUE_FULL is not set and is only cleared.
Therefore, define is unnecessary.

Signed-off-by: ChanWoo Lee <[email protected]>
Acked-by: Adrian Hunter <ad

mmc: queue: Remove unused define

MMC_CQE_QUEUE_FULL is not set and is only cleared.
Therefore, define is unnecessary.

Signed-off-by: ChanWoo Lee <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

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mmc: stop abusing the request queue_lock pointer

Replace the lock in mmc_blk_data that is only used through a pointer
in struct mmc_queue and to protect fields in that structure with
an actual lock

mmc: stop abusing the request queue_lock pointer

Replace the lock in mmc_blk_data that is only used through a pointer
in struct mmc_queue and to protect fields in that structure with
an actual lock in struct mmc_queue.

Suggested-by: Ulf Hansson <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

show more ...

mmc: stop abusing the request queue_lock pointer

mmc uses the block layer struct request pointer to indirect their own
lock to the mmc_queue structure, given that the original lock isn't
reachable o

mmc: stop abusing the request queue_lock pointer

mmc uses the block layer struct request pointer to indirect their own
lock to the mmc_queue structure, given that the original lock isn't
reachable outside of block.c. Add a lock pointer to struct mmc_queue
instead and stop overriding the block layer lock which protects fields
entirely separate from the mmc use.

Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

show more ...

mmc: simplify queue initialization

Merge three functions initializing the queue into a single one, and drop
an unused argument for it.

Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by:

mmc: simplify queue initialization

Merge three functions initializing the queue into a single one, and drop
an unused argument for it.

Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

show more ...

mmc: block: Fix unsupported parallel dispatch of requests

The mmc block driver does not support parallel dispatch of requests. In
normal circumstances, all requests are anyway funneled through a sin

mmc: block: Fix unsupported parallel dispatch of requests

The mmc block driver does not support parallel dispatch of requests. In
normal circumstances, all requests are anyway funneled through a single
work item, so parallel dispatch never happens. However it can happen if
there is no elevator.

Fix that by detecting if a dispatch is in progress and returning busy
(BLK_STS_RESOURCE) in that case

Fixes: 81196976ed94 ("mmc: block: Add blk-mq support")
Cc: [email protected] # v4.16+
Signed-off-by: Adrian Hunter <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: Remove code no longer needed after the switch to blk-mq

Remove code no longer needed after the switch to blk-mq.

Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Linus W

mmc: block: Remove code no longer needed after the switch to blk-mq

Remove code no longer needed after the switch to blk-mq.

Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Tested-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: blk-mq: Add support for direct completion

For blk-mq, add support for completing requests directly in the ->done
callback. That means that error handling and urgent background operations

mmc: block: blk-mq: Add support for direct completion

For blk-mq, add support for completing requests directly in the ->done
callback. That means that error handling and urgent background operations
must be handled by recovery_work in that case.

Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Linus Walleij <[email protected]>

show more ...

mmc: block: Add CQE support

Add CQE support to the block driver, including:
- optionally using DCMD for flush requests
- "manually" issuing discard requests
- issuing read / write reques

mmc: block: Add CQE support

Add CQE support to the block driver, including:
- optionally using DCMD for flush requests
- "manually" issuing discard requests
- issuing read / write requests to the CQE
- supporting block-layer timeouts
- handling recovery
- supporting re-tuning

CQE offers 25% - 50% better random multi-threaded I/O. There is a slight
(e.g. 2%) drop in sequential read speed but no observable change to sequential
write.

CQE automatically sends the commands to complete requests. However it only
supports reads / writes and so-called "direct commands" (DCMD). Furthermore
DCMD is limited to one command at a time, but discards require 3 commands.
That makes issuing discards through CQE very awkward, but some CQE's don't
support DCMD anyway. So for discards, the existing non-CQE approach is
taken, where the mmc core code issues the 3 commands one at a time i.e.
mmc_erase(). Where DCMD is used, is for issuing flushes.

Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Linus Walleij <[email protected]>

show more ...

mmc: block: Add blk-mq support

Define and use a blk-mq queue. Discards and flushes are processed
synchronously, but reads and writes asynchronously. In order to support
slow DMA unmapping, DMA unmap

mmc: block: Add blk-mq support

Define and use a blk-mq queue. Discards and flushes are processed
synchronously, but reads and writes asynchronously. In order to support
slow DMA unmapping, DMA unmapping is not done until after the next request
is started. That means the request is not completed until then. If there is
no next request then the completion is done by queued work.

Signed-off-by: Adrian Hunter <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Linus Walleij <[email protected]>

show more ...

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

mmc: block: Delete mmc_access_rpmb()

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 tim

mmc: block: Delete mmc_access_rpmb()

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 <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: Convert RPMB to a character device

The RPMB partition on the eMMC devices is a special area used
for storing cryptographically safe information signed by a
special secret key. To write a

mmc: block: Convert RPMB to a character device

The RPMB partition on the eMMC devices is a special area used
for storing cryptographically safe information signed by a
special secret key. To write and read records from this special
area, authentication is needed.

The RPMB area is *only* and *exclusively* accessed using
ioctl():s from userspace. It is not really a block device,
as blocks cannot be read or written from the device, also
the signed chunks that can be stored on the RPMB are actually
256 bytes, not 512 making a block device a real bad fit.

Currently the RPMB partition spawns a separate block device
named /dev/mmcblkNrpmb for each device with an RPMB partition,
including the creation of a block queue with its own kernel
thread and all overhead associated with this. On the Ux500
HREFv60 platform, for example, the two eMMCs means that two
block queues with separate threads are created for no use
whatsoever.

I have concluded that this block device design for RPMB is
actually pretty wrong. The RPMB area should have been designed
to be accessed from /dev/mmcblkN directly, using ioctl()s on
the main block device. It is however way too late to change
that, since userspace expects to open an RPMB device in
/dev/mmcblkNrpmb and we cannot break userspace.

This patch tries to amend the situation using the following
strategy:

- Stop creating a block device for the RPMB partition/area

- Instead create a custom, dynamic character device with
the same name.

- Make this new character device support exactly the same
set of ioctl()s as the old block device.

- Wrap the requests back to the same ioctl() handlers, but
issue them on the block queue of the main partition/area,
i.e. /dev/mmcblkN

We need to create a special "rpmb" bus type in order to get
udev and/or busybox hot/coldplug to instantiate the device
node properly.

Before the patch, this appears in 'ps aux':

101 root 0:00 [mmcqd/2rpmb]
123 root 0:00 [mmcqd/3rpmb]

After applying the patch these surplus block queue threads
are gone, but RPMB is as usable as ever using the userspace
MMC tools, such as 'mmc rpmb read-counter'.

We get instead those dynamice devices in /dev:

brw-rw---- 1 root root 179, 0 Jan 1 2000 mmcblk0
brw-rw---- 1 root root 179, 1 Jan 1 2000 mmcblk0p1
brw-rw---- 1 root root 179, 2 Jan 1 2000 mmcblk0p2
brw-rw---- 1 root root 179, 5 Jan 1 2000 mmcblk0p5
brw-rw---- 1 root root 179, 8 Jan 1 2000 mmcblk2
brw-rw---- 1 root root 179, 16 Jan 1 2000 mmcblk2boot0
brw-rw---- 1 root root 179, 24 Jan 1 2000 mmcblk2boot1
crw-rw---- 1 root root 248, 0 Jan 1 2000 mmcblk2rpmb
brw-rw---- 1 root root 179, 32 Jan 1 2000 mmcblk3
brw-rw---- 1 root root 179, 40 Jan 1 2000 mmcblk3boot0
brw-rw---- 1 root root 179, 48 Jan 1 2000 mmcblk3boot1
brw-rw---- 1 root root 179, 33 Jan 1 2000 mmcblk3p1
crw-rw---- 1 root root 248, 1 Jan 1 2000 mmcblk3rpmb

Notice the (248,0) and (248,1) character devices for RPMB.

Cc: Tomas Winkler <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: Delete bounce buffer handling

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 conf

mmc: Delete bounce buffer handling

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 a45c6cb81647 ("[ARM] 5369/1: omap mmc: Add new
omap hsmmc controller for 2430 and 34xx, v3")

This optimization was removed in
commit 0ccd76d4c236 ("omap_hsmmc: Implement scatter-gather
emulation")
which found that scatter-gather emulation provided even
better performance.

The same was introduced for SDHCI in
commit 2134a922c6e7 ("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 <[email protected]>
Cc: Juha Yrjola <[email protected]>
Cc: Steven J. Hill <[email protected]>
Cc: Shawn Lin <[email protected]>
Cc: Adrian Hunter <[email protected]>
Suggested-by: Steven J. Hill <[email protected]>
Suggested-by: Shawn Lin <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: debugfs: Move block debugfs into block module

If we don't have the block layer enabled, we do not present card
status and extcsd in the debugfs.

Debugfs is not ABI, and maintaining files of no

mmc: debugfs: Move block debugfs into block module

If we don't have the block layer enabled, we do not present card
status and extcsd in the debugfs.

Debugfs is not ABI, and maintaining files of no relevance for
non-block devices comes at a high maintenance cost if we shall
support it with the block layer compiled out.

The debugfs entries suffer from all the same starvation
issues as the other userspace things, under e.g. a heavy
dd operation.

The expected number of debugfs users utilizing these two
debugfs files is already low as there is an ioctl() to get the
same information using the mmc-tools, and of these few users
the expected number of people using it on SDIO or combo cards
are expected to be zero.

It is therefore logical to move this over to the block layer
when it is enabled, using the new custom requests and issue
it using the block request queue.

On the other hand it moves some debugfs code from debugfs.c
and into block.c.

Tested during heavy dd load by cat:in the status file.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: Anonymize the drv op data pointer

We have a data pointer for the ioctl() data, but we need to
pass other data along with the DRV_OP:s, so make this a
void * so it can be reused.

Signed-

mmc: block: Anonymize the drv op data pointer

We have a data pointer for the ioctl() data, but we need to
pass other data along with the DRV_OP:s, so make this a
void * so it can be reused.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: Move boot partition locking into a driver op

This moves the boot partition lock command (issued from sysfs)
into a custom block layer request, just like the ioctl()s,
getting rid of yet

mmc: block: Move boot partition locking into a driver op

This moves the boot partition lock command (issued from sysfs)
into a custom block layer request, just like the ioctl()s,
getting rid of yet another instance of mmc_get_card().

Since we now have two operations issuing special DRV_OP's, we
rename the result variable ->drv_op_result.

Tested by locking the boot partition from userspace:
> cd /sys/devices/platform/soc/80114000.sdi4_per2/mmc_host/mmc3/
mmc3:0001/block/mmcblk3/mmcblk3boot0
> echo 1 > ro_lock_until_next_power_on
[ 178.645324] mmcblk3boot1: Locking boot partition ro until next power on
[ 178.652221] mmcblk3boot0: Locking boot partition ro until next power on

Also tested this with a huge dd job in the background: it
is now possible to lock the boot partitions on the card even
under heavy I/O.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: Tag DRV_OPs with a driver operation type

We will expand the DRV_OP usage, so we need to know which
operation we're performing. Tag the operations with an
enum:ed type and rename the func

mmc: block: Tag DRV_OPs with a driver operation type

We will expand the DRV_OP usage, so we need to know which
operation we're performing. Tag the operations with an
enum:ed type and rename the function so it is clear that
it deals with any command and put a switch statement in
it. Currently only ioctls are supported.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: block: remove req back pointer

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

mmc: block: remove req back pointer

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: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

show more ...

mmc: queue: delete mmc_req_is_special()

commit cdf8a6fb48882651049e468e6b16956fb83db86c
"mmc: block: Introduce queue semantics"
deleted the last user of mmc_req_is_special() and it was
a horrible ha

mmc: queue: delete mmc_req_is_special()

commit cdf8a6fb48882651049e468e6b16956fb83db86c
"mmc: block: Introduce queue semantics"
deleted the last user of mmc_req_is_special() and it was
a horrible hack to classify requests as "special" or
"not special" to begin with, so delete the helper.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>

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mmc: block: move multi-ioctl() to use block layer

This switches also the multiple-command ioctl() call to issue
all ioctl()s through the block layer instead of going directly
to the device.

We exte

mmc: block: move multi-ioctl() to use block layer

This switches also the multiple-command ioctl() call to issue
all ioctl()s through the block layer instead of going directly
to the device.

We extend the passed argument with an argument count and loop
over all passed commands in the ioctl() issue function called
from the block layer.

By doing this we are again loosening the grip on the big host
lock, since two calls to mmc_get_card()/mmc_put_card() are
removed.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Avri Altman <[email protected]>

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mmc: block: move single ioctl() commands to block requests

This wraps single ioctl() commands into block requests using
the custom block layer request types REQ_OP_DRV_IN and
REQ_OP_DRV_OUT.

By doi

mmc: block: move single ioctl() commands to block requests

This wraps single ioctl() commands into block requests using
the custom block layer request types REQ_OP_DRV_IN and
REQ_OP_DRV_OUT.

By doing this we are loosening the grip on the big host lock,
since two calls to mmc_get_card()/mmc_put_card() are removed.

We are storing the ioctl() in/out argument as a pointer in
the per-request struct mmc_blk_request container. Since we
now let the block layer allocate this data, blk_get_request()
will allocate it for us and we can immediately dereference
it and use it to pass the argument into the block layer.

We refactor the if/else/if/else ladder in mmc_blk_issue_rq()
as part of the job, keeping some extra attention to the
case when a NULL req is passed into this function and
making that pipeline flush more explicit.

Tested on the ux500 with the userspace:
mmc extcsd read /dev/mmcblk3
resulting in a successful EXTCSD info dump back to the
console.

This commit fixes a starvation issue in the MMC/SD stack
that can be easily provoked in the following way by
issueing the following commands in sequence:

> dd if=/dev/mmcblk3 of=/dev/null bs=1M &
> mmc extcs read /dev/mmcblk3

Before this patch, the extcsd read command would hang
(starve) while waiting for the dd command to finish since
the block layer was holding the card/host lock.

After this patch, the extcsd ioctl() command is nicely
interpersed with the rest of the block commands and we
can issue a bunch of ioctl()s from userspace while there
is some busy block IO going on without any problems.

Conversely userspace ioctl()s can no longer starve
the block layer by holding the card/host lock.

Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Avri Altman <[email protected]>

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mmc: core: Allocate per-request data using the block layer core

The mmc_queue_req is a per-request state container the MMC core uses
to carry bounce buffers, pointers to asynchronous requests and so

mmc: core: Allocate per-request data using the block layer core

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: Linus Walleij <[email protected]>
[Ulf: Folded in the fix to drop a call to blk_cleanup_queue()]
Signed-off-by: Ulf Hansson <[email protected]>
Tested-by: Heiner Kallweit <[email protected]>

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