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>

3 files changed, 29 insertions, 28 deletions

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 367509b5b646..2c9963248fcb 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2466,8 +2466,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	struct mmc_blk_data *md;
 	int devidx, ret;
 	char cap_str[10];
-	bool cache_enabled = false;
-	bool fua_enabled = false;
+	unsigned int features = 0;
 
 	devidx = ida_alloc_max(&mmc_blk_ida, max_devices - 1, GFP_KERNEL);
 	if (devidx < 0) {
@@ -2499,7 +2498,24 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	 */
 	md->read_only = mmc_blk_readonly(card);
 
-	md->disk = mmc_init_queue(&md->queue, card);
+	if (mmc_host_cmd23(card->host)) {
+		if ((mmc_card_mmc(card) &&
+		     card->csd.mmca_vsn >= CSD_SPEC_VER_3) ||
+		    (mmc_card_sd(card) &&
+		     card->scr.cmds & SD_SCR_CMD23_SUPPORT))
+			md->flags |= MMC_BLK_CMD23;
+	}
+
+	if (md->flags & MMC_BLK_CMD23 &&
+	    ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
+	     card->ext_csd.rel_sectors)) {
+		md->flags |= MMC_BLK_REL_WR;
+		features |= (BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA);
+	} else if (mmc_cache_enabled(card->host)) {
+		features |= BLK_FEAT_WRITE_CACHE;
+	}
+
+	md->disk = mmc_init_queue(&md->queue, card, features);
 	if (IS_ERR(md->disk)) {
 		ret = PTR_ERR(md->disk);
 		goto err_kfree;
@@ -2539,26 +2555,6 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 
 	set_capacity(md->disk, size);
 
-	if (mmc_host_cmd23(card->host)) {
-		if ((mmc_card_mmc(card) &&
-		     card->csd.mmca_vsn >= CSD_SPEC_VER_3) ||
-		    (mmc_card_sd(card) &&
-		     card->scr.cmds & SD_SCR_CMD23_SUPPORT))
-			md->flags |= MMC_BLK_CMD23;
-	}
-
-	if (md->flags & MMC_BLK_CMD23 &&
-	    ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
-	     card->ext_csd.rel_sectors)) {
-		md->flags |= MMC_BLK_REL_WR;
-		fua_enabled = true;
-		cache_enabled = true;
-	}
-	if (mmc_cache_enabled(card->host))
-		cache_enabled  = true;
-
-	blk_queue_write_cache(md->queue.queue, cache_enabled, fua_enabled);
-
 	string_get_size((u64)size, 512, STRING_UNITS_2,
 			cap_str, sizeof(cap_str));
 	pr_info("%s: %s %s %s%s\n",
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 241cdc2b2a2a..97ff993d3157 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -344,10 +344,12 @@ static const struct blk_mq_ops mmc_mq_ops = {
 };
 
 static struct gendisk *mmc_alloc_disk(struct mmc_queue *mq,
-		struct mmc_card *card)
+		struct mmc_card *card, unsigned int features)
 {
 	struct mmc_host *host = card->host;
-	struct queue_limits lim = { };
+	struct queue_limits lim = {
+		.features		= features,
+	};
 	struct gendisk *disk;
 
 	if (mmc_can_erase(card))
@@ -413,10 +415,12 @@ static inline bool mmc_merge_capable(struct mmc_host *host)
  * mmc_init_queue - initialise a queue structure.
  * @mq: mmc queue
  * @card: mmc card to attach this queue
+ * @features: block layer features (BLK_FEAT_*)
  *
  * Initialise a MMC card request queue.
  */
-struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)
+struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
+		unsigned int features)
 {
 	struct mmc_host *host = card->host;
 	struct gendisk *disk;
@@ -460,7 +464,7 @@ struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)
 		return ERR_PTR(ret);
 		
 
-	disk = mmc_alloc_disk(mq, card);
+	disk = mmc_alloc_disk(mq, card, features);
 	if (IS_ERR(disk))
 		blk_mq_free_tag_set(&mq->tag_set);
 	return disk;
diff --git a/drivers/mmc/core/queue.h b/drivers/mmc/core/queue.h
index 9ade3bcbb714..1498840a4ea0 100644
--- a/drivers/mmc/core/queue.h
+++ b/drivers/mmc/core/queue.h
@@ -94,7 +94,8 @@ struct mmc_queue {
 	struct work_struct	complete_work;
 };
 
-struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card);
+struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
+		unsigned int features);
 extern void mmc_cleanup_queue(struct mmc_queue *);
 extern void mmc_queue_suspend(struct mmc_queue *);
 extern void mmc_queue_resume(struct mmc_queue *);