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| author | Christoph Hellwig <hch@lst.de> | 2023-07-07 11:42:39 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-07-17 08:18:18 -0600 |
| commit | 43c9835b144c7ce29efe142d662529662a9eb376 (patch) | |
| tree | 9a76f7e28e76f520ceb20966493710c10bcc49cb /block/blk-sysfs.c | |
| parent | c4e21bcd0f9d01f9c5d6c52007f5541871a5b1de (diff) | |
| download | lwn-43c9835b144c7ce29efe142d662529662a9eb376.tar.gz lwn-43c9835b144c7ce29efe142d662529662a9eb376.zip | |
block: don't allow enabling a cache on devices that don't support it
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: 93e9d8e836cb ("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>
Diffstat (limited to 'block/blk-sysfs.c')
| -rw-r--r-- | block/blk-sysfs.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 0cde6598fb2f..63e481262336 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -449,13 +449,16 @@ static ssize_t queue_wc_show(struct request_queue *q, char *page) static ssize_t queue_wc_store(struct request_queue *q, const char *page, size_t count) { - if (!strncmp(page, "write back", 10)) + if (!strncmp(page, "write back", 10)) { + if (!test_bit(QUEUE_FLAG_HW_WC, &q->queue_flags)) + return -EINVAL; blk_queue_flag_set(QUEUE_FLAG_WC, q); - else if (!strncmp(page, "write through", 13) || - !strncmp(page, "none", 4)) + } else if (!strncmp(page, "write through", 13) || + !strncmp(page, "none", 4)) { blk_queue_flag_clear(QUEUE_FLAG_WC, q); - else + } else { return -EINVAL; + } return count; } |