block: don't allow enabling a cache on devices that don't support it

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[ Upstream commit 43c9835b14 ]

Currently the write_cache attribute allows enabling the QUEUE_FLAG_WC
flag on devices that never claimed the capability.

Fix that by adding a QUEUE_FLAG_HW_WC flag that is set by
blk_queue_write_cache and guards re-enabling the cache through sysfs.

Note that any rescan that calls blk_queue_write_cache will still
re-enable the write cache as in the current code.

Fixes: 93e9d8e836 ("block: add ability to flag write back caching on a device")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230707094239.107968-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Christoph Hellwig 2023-07-07 11:42:39 +02:00 • committed by Greg Kroah-Hartman

parent db22fcbad5

commit 4355a1c3a5

3 changed files with 13 additions and 6 deletions

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7

block/blk-settings.c

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11

block/blk-sysfs.c

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1

include/linux/blkdev.h

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