linux/include
Stanley Chu 0fef6bb730 scsi: ufs: core: mcq: Fix the incorrect OCS value for the device command
In MCQ mode, when a device command uses a hardware queue shared with other
commands, a race condition may occur in the following scenario:

 1. A device command is completed in CQx with CQE entry "e".

 2. The interrupt handler copies the "cqe" pointer to "hba->dev_cmd.cqe"
    and completes "hba->dev_cmd.complete".

 3. The "ufshcd_wait_for_dev_cmd()" function is awakened and retrieves the
    OCS value from "hba->dev_cmd.cqe".

However, there is a possibility that the CQE entry "e" will be overwritten
by newly completed commands in CQx, resulting in an incorrect OCS value
being received by "ufshcd_wait_for_dev_cmd()".

To avoid this race condition, the OCS value should be immediately copied to
the struct "lrb" of the device command. Then "ufshcd_wait_for_dev_cmd()"
can retrieve the OCS value from the struct "lrb".

Fixes: 57b1c0ef89 ("scsi: ufs: core: mcq: Add support to allocate multiple queues")
Suggested-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Link: https://lore.kernel.org/r/20230610021553.1213-2-powen.kao@mediatek.com
Tested-by: Po-Wen Kao <powen.kao@mediatek.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2023-06-16 12:04:30 -04:00
..
acpi Power management updates for 6.4-rc1 2023-04-25 18:44:10 -07:00
asm-generic Locking changes in v6.4: 2023-05-05 12:56:55 -07:00
clocksource
crypto This update includes the following changes: 2023-04-26 08:32:52 -07:00
drm - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of 2023-04-27 19:42:02 -07:00
dt-bindings - mailbox api: allow direct registration to a channel 2023-05-07 10:17:33 -07:00
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kvm s390: 2023-05-01 12:06:20 -07:00
linux Merge patch series "Add Command Duration Limits support" 2023-05-22 17:09:51 -04:00
math-emu
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net Including fixes from netfilter. 2023-05-05 19:12:01 -07:00
pcmcia
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rv
scsi Merge patch series "ufs: Do not requeue while ungating the clock" 2023-05-31 11:45:16 -04:00
soc Nothing looks out of the ordinary in this batch of clk driver updates. There 2023-04-29 17:29:39 -07:00
sound
target Merge patch series "Use block pr_ops in LIO" 2023-05-22 16:35:02 -04:00
trace scsi: core: Trace SCSI sense data 2023-05-31 11:05:34 -04:00
uapi scsi: block: Improve ioprio value validity checks 2023-06-16 12:04:30 -04:00
ufs scsi: ufs: core: mcq: Fix the incorrect OCS value for the device command 2023-06-16 12:04:30 -04:00
vdso
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