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: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Harjani Ritesh <riteshh@codeaurora.org>
Signed-off-by: Ulf 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 ce39f9d17c ("mmc: support packed write command for eMMC4.5
devices")
commit abd9ac1449 ("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: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf 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: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The struct mmc_blk_request contains an opaque void *data that
is actually only used to store a pointer to a per-request
struct mmc_blk_data. This is confusing, so rename the member
to blkdata and forward-declare the block.c local struct.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Commit 288dab8a35 ("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: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 288dab8a35 ("block: add a separate operation type for secure erase")
Signed-off-by: Jens Axboe <axboe@fb.com>
This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens 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: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Retry errored data requests when re-tuning is needed and
add a flag to struct mmc_blk_request so that the retry
is only done once.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf 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: 090d25fe22 ("mmc: core: Expose access to RPMB partition")
Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Tested-by: Michael Shigorin <mike@altlinux.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
For normal request mmc_blk_issue_rq is called twice with asynchronous
transfer(cur and prev). Host's claim and release can be done in each
mmc_blk_issue_rq. However, Special request is currently excluded in
asynchronous transfer. After special request is finished, if there is
no new request, mmc_release_host won't be called in mmc_blk_issue_rq.
The problem is founded during mmc_suspend.
[<c0541124>] (__schedule+0x0/0x78c) from [<c05419e8>] (schedule+0x38/0x78)
[<c05419b0>] (schedule+0x0/0x78) from [<c03a843c>] (__mmc_claim_host+0xac/0x1b4)
[<c03a8390>] (__mmc_claim_host+0x0/0x1b4) from [<c03ac98c>] (mmc_suspend+0x28/0x9c)
[<c03ac964>] (mmc_suspend+0x0/0x9c) from [<c03aad24>] (mmc_suspend_host+0xb4/0x194)
...
Reported-by: Johan Rudholm <jrudholm@gmail.com>
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Tested-by: Johan Rudholm <johan.rudholm@stericsson.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This patch supports packed write command of eMMC4.5 devices. Several
writes can be grouped in packed command and all data of the individual
commands can be sent in a single transfer on the bus. Large amounts of
data in one transfer rather than several data of small size are
effective for eMMC write internally. As a result, packed command help
write throughput be improved. The following tables show the results
of packed write.
Type A:
test none | packed
iozone 25.8 | 31
tiotest 27.6 | 31.2
lmdd 31.2 | 35.4
Type B:
test none | packed
iozone 44.1 | 51.1
tiotest 47.9 | 52.5
lmdd 51.6 | 59.2
Type C:
test none | packed
iozone 19.5 | 32
tiotest 19.9 | 34.5
lmdd 22.8 | 40.7
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
When current request is running on the bus and if next request fetched
by mmcqd is NULL, mmc context (mmcqd thread) gets blocked until the
current request completes. This means that if new request comes in while
the mmcqd thread is blocked, this new request can not be prepared in
parallel to current ongoing request. This may result in delaying the new
request execution and increase it's latency.
This change allows to wake up the MMC thread on new request arrival.
Now once the MMC thread is woken up, a new request can be fetched and
prepared in parallel to the current running request which means this new
request can be started immediately after the current running request
completes.
With this change read throughput is improved by 16%.
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
Reviewed-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Change mmc_blk_issue_rw_rq() to become asynchronous.
The execution flow looks like this:
* The mmc-queue calls issue_rw_rq(), which sends the request
to the host and returns back to the mmc-queue.
* The mmc-queue calls issue_rw_rq() again with a new request.
* This new request is prepared in issue_rw_rq(), then it waits for
the active request to complete before pushing it to the host.
* When the mmc-queue is empty it will call issue_rw_rq() with a NULL
req to finish off the active request without starting a new request.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Venkatraman S <svenkatr@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
Add an additional mmc queue request instance to make way for two active
block requests. One request may be active while the other request is
being prepared.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Venkatraman S <svenkatr@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
The way the request data is organized in the mmc queue struct, it only
allows processing of one request at a time. This patch adds a new struct
to hold mmc queue request data such as sg list, request, blk request and
bounce buffers, and updates any functions depending on the mmc queue
struct. This prepares for using multiple active requests in one mmc queue.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Venkatraman S <svenkatr@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
For example, an eMMC with 2 boot partitions will have 3 threads.
The names change from:
40 ? 00:00:00 mmcqd/0
41 ? 00:00:00 mmcqd/0
42 ? 00:00:00 mmcqd/0
to:
40 ? 00:00:00 mmcqd/0
41 ? 00:00:00 mmcqd/0boot0
42 ? 00:00:00 mmcqd/0boot1
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrei Warkentin <andreiw@motorola.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Some hosts cannot do scatter/gather in hardware. Since not doing sg
is such a big performance hit, we (optionally) bounce the requests
to a simple linear buffer that we hand over to the driver.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
