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authorChristoph Hellwig <hch@lst.de>2023-07-07 11:42:39 +0200
committerJens Axboe <axboe@kernel.dk>2023-07-17 08:18:18 -0600
commit43c9835b144c7ce29efe142d662529662a9eb376 (patch)
tree9a76f7e28e76f520ceb20966493710c10bcc49cb /block
parentc4e21bcd0f9d01f9c5d6c52007f5541871a5b1de (diff)
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')
-rw-r--r--block/blk-settings.c7
-rw-r--r--block/blk-sysfs.c11
2 files changed, 12 insertions, 6 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 4dd59059b788..0046b447268f 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -830,10 +830,13 @@ EXPORT_SYMBOL(blk_set_queue_depth);
*/
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
- if (wc)
+ if (wc) {
+ blk_queue_flag_set(QUEUE_FLAG_HW_WC, q);
blk_queue_flag_set(QUEUE_FLAG_WC, q);
- else
+ } else {
+ blk_queue_flag_clear(QUEUE_FLAG_HW_WC, q);
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
+ }
if (fua)
blk_queue_flag_set(QUEUE_FLAG_FUA, q);
else
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;
}