[ Upstream commit
43c9835b144c7ce29efe142d662529662a9eb376 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
*/
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
*/
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
+ if (wc) {
+ blk_queue_flag_set(QUEUE_FLAG_HW_WC, q);
blk_queue_flag_set(QUEUE_FLAG_WC, q);
blk_queue_flag_set(QUEUE_FLAG_WC, q);
+ } else {
+ blk_queue_flag_clear(QUEUE_FLAG_HW_WC, q);
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
if (fua)
blk_queue_flag_set(QUEUE_FLAG_FUA, q);
else
if (fua)
blk_queue_flag_set(QUEUE_FLAG_FUA, q);
else
static ssize_t queue_wc_store(struct request_queue *q, const char *page,
size_t count)
{
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);
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);
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
#define QUEUE_FLAG_NOXMERGES 9 /* No extended merges */
#define QUEUE_FLAG_ADD_RANDOM 10 /* Contributes to random pool */
#define QUEUE_FLAG_SAME_FORCE 12 /* force complete on same CPU */
#define QUEUE_FLAG_NOXMERGES 9 /* No extended merges */
#define QUEUE_FLAG_ADD_RANDOM 10 /* Contributes to random pool */
#define QUEUE_FLAG_SAME_FORCE 12 /* force complete on same CPU */
+#define QUEUE_FLAG_HW_WC 18 /* Write back caching supported */
#define QUEUE_FLAG_INIT_DONE 14 /* queue is initialized */
#define QUEUE_FLAG_STABLE_WRITES 15 /* don't modify blks until WB is done */
#define QUEUE_FLAG_POLL 16 /* IO polling enabled if set */
#define QUEUE_FLAG_INIT_DONE 14 /* queue is initialized */
#define QUEUE_FLAG_STABLE_WRITES 15 /* don't modify blks until WB is done */
#define QUEUE_FLAG_POLL 16 /* IO polling enabled if set */