Commit 8b859496 authored by Kiwoong Kim's avatar Kiwoong Kim Committed by Zheng Zengkai
Browse files

scsi: ufs: Introduce a quirk to allow only page-aligned sg entries

stable inclusion
from stable-5.10.23
commit c32b34115357ca555189b48296bbd4242b5cd256
bugzilla: 50838

--------------------------------

[ Upstream commit 2b2bfc8a ]

Some SoCs require a single scatterlist entry for smaller than page size,
i.e. 4KB. When dispatching commands with more than one scatterlist entry
under 4KB in size the following behavior is observed:

A command to read a block range is dispatched with two scatterlist entries
that are named AAA and BBB. After dispatching, the host builds two PRDT
entries and during transmission, device sends just one DATA IN because
device doesn't care about host DMA. The host then transfers the combined
amount of data from start address of the area named AAA. As a consequence,
the area that follows AAA in memory would be corrupted.

    |<------------->|
    +-------+------------         +-------+
    +  AAA  + (corrupted)   ...   +  BBB  +
    +-------+------------         +-------+

To avoid this we need to enforce page size alignment for sg entries.

Link: https://lore.kernel.org/r/56dddef94f60bd9466fd77e69f64bbbd657ed2a1.1611026909.git.kwmad.kim@samsung.com


Signed-off-by: default avatarKiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarChen Jun <chenjun102@huawei.com>
Acked-by: default avatar  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent cb4fb020
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