block: move cache control settings out of queue->flags
Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.
Add new features and flags field for the driver set flags, and internal
(usually sysfs-controlled) flags in the block layer. Note that we'll
eventually remove enough field from queue_limits to bring it back to the
previous size.
The disable flag is inverted compared to the previous meaning, which
means it now survives a rescan, similar to the max_sectors and
max_discard_sectors user limits.
The FLUSH and FUA flags are now inherited by blk_stack_limits, which
simplified the code in dm a lot, but also causes a slight behavior
change in that dm-switch and dm-unstripe now advertise a write cache
despite setting num_flush_bios to 0. The I/O path will handle this
gracefully, but as far as I can tell the lack of num_flush_bios
and thus flush support is a pre-existing data integrity bug in those
targets that really needs fixing, after which a non-zero num_flush_bios
should be required in dm for targets that map to underlying devices.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index 82c3ae2..2b45a4d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -782,7 +782,7 @@ void submit_bio_noacct(struct bio *bio)
if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE &&
bio_op(bio) != REQ_OP_ZONE_APPEND))
goto end_io;
- if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
+ if (!bdev_write_cache(bdev)) {
bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
if (!bio_sectors(bio)) {
status = BLK_STS_OK;
