gistfile1.txt

commit 9fe21de5134c4321667eb2aa03f3f3d0d0524ee7
Author: Andres Freund <andres@anarazel.de>
Date:   2020-12-28 11:46:36 -0800

    WIP: block: Allow disabling fua support via sysfs.

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 76c1624cb06c..914f8748fa20 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -105,7 +105,7 @@ static unsigned int blk_flush_policy(unsigned long fflags, struct request *rq)
 	if (fflags & (1UL << QUEUE_FLAG_WC)) {
 		if (rq->cmd_flags & REQ_PREFLUSH)
 			policy |= REQ_FSEQ_PREFLUSH;
-		if (!(fflags & (1UL << QUEUE_FLAG_FUA)) &&
+		if (!(fflags & (1UL << QUEUE_FLAG_FUA_ENABLED)) &&
 		    (rq->cmd_flags & REQ_FUA))
 			policy |= REQ_FSEQ_POSTFLUSH;
 	}
@@ -379,7 +379,7 @@ void blk_insert_flush(struct request *rq)
 	 * REQ_PREFLUSH and FUA for the driver.
 	 */
 	rq->cmd_flags &= ~REQ_PREFLUSH;
-	if (!(fflags & (1UL << QUEUE_FLAG_FUA)))
+	if (!(fflags & (1UL << QUEUE_FLAG_FUA_ENABLED)))
 		rq->cmd_flags &= ~REQ_FUA;
 
 	/*
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 4de03da9a624..c843e240d4f7 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -119,7 +119,7 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(STABLE_WRITES),
 	QUEUE_FLAG_NAME(POLL),
 	QUEUE_FLAG_NAME(WC),
-	QUEUE_FLAG_NAME(FUA),
+	QUEUE_FLAG_NAME(FUA_HW),
 	QUEUE_FLAG_NAME(DAX),
 	QUEUE_FLAG_NAME(STATS),
 	QUEUE_FLAG_NAME(POLL_STATS),
@@ -130,6 +130,7 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(ZONE_RESETALL),
 	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
 	QUEUE_FLAG_NAME(NOWAIT),
+	QUEUE_FLAG_NAME(FUA_ENABLED),
 };
 #undef QUEUE_FLAG_NAME
 
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 43990b1d148b..8bf0c8a60300 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -786,10 +786,14 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 		blk_queue_flag_set(QUEUE_FLAG_WC, q);
 	else
 		blk_queue_flag_clear(QUEUE_FLAG_WC, q);
-	if (fua)
-		blk_queue_flag_set(QUEUE_FLAG_FUA, q);
-	else
-		blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
+	if (fua) {
+		blk_queue_flag_set(QUEUE_FLAG_FUA_HW, q);
+		blk_queue_flag_set(QUEUE_FLAG_FUA_ENABLED, q);
+	}
+	else {
+		blk_queue_flag_clear(QUEUE_FLAG_FUA_HW, q);
+		blk_queue_flag_clear(QUEUE_FLAG_FUA_ENABLED, q);
+	}
 
 	wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 }
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index b513f1683af0..e9562ed6ac37 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -540,7 +540,31 @@ static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 
 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 {
-	return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
+	return sprintf(page, "%u\n",
+		       test_bit(QUEUE_FLAG_FUA_ENABLED, &q->queue_flags));
+}
+
+static ssize_t queue_fua_store(struct request_queue *q, const char *page, size_t count)
+{
+	int ret;
+	unsigned long set_fua_to;
+
+	ret = queue_var_store(&set_fua_to, page, count);
+	if (ret < 0)
+		return ret;
+
+	if (set_fua_to != 0 && set_fua_to != 1)
+		return -EINVAL;
+
+	if (set_fua_to && !test_bit(QUEUE_FLAG_FUA_HW, &q->queue_flags))
+		return -ENOTSUPP;
+
+	if (set_fua_to)
+		blk_queue_flag_set(QUEUE_FLAG_FUA_ENABLED, q);
+	else
+		blk_queue_flag_clear(QUEUE_FLAG_FUA_ENABLED, q);
+
+	return count;
 }
 
 static ssize_t queue_dax_show(struct request_queue *q, char *page)
@@ -596,7 +620,7 @@ QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 QUEUE_RW_ENTRY(queue_poll, "io_poll");
 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
 QUEUE_RW_ENTRY(queue_wc, "write_cache");
-QUEUE_RO_ENTRY(queue_fua, "fua");
+QUEUE_RW_ENTRY(queue_fua, "fua");
 QUEUE_RO_ENTRY(queue_dax, "dax");
 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4acf2342f7ad..9c8f2720bff5 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1832,7 +1832,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 
 	if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
 		wc = true;
-		if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
+		if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA_HW)))
 			fua = true;
 	}
 	blk_queue_write_cache(q, wc, fua);
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 8ed93fd205c7..ae0fd98f6879 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -700,7 +700,7 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 		 * is not enabled, or if initiator set the Force Unit Access bit.
 		 */
 		op = REQ_OP_WRITE;
-		if (test_bit(QUEUE_FLAG_FUA, &q->queue_flags)) {
+		if (test_bit(QUEUE_FLAG_FUA_ENABLED, &q->queue_flags)) {
 			if (cmd->se_cmd_flags & SCF_FUA)
 				op_flags = REQ_FUA;
 			else if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags))
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f94ee3089e01..6d30e193fd14 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -609,7 +609,7 @@ struct request_queue {
 #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_WC		17	/* Write back caching */
-#define QUEUE_FLAG_FUA		18	/* device supports FUA writes */
+#define QUEUE_FLAG_FUA_HW	18	/* device supports FUA writes */
 #define QUEUE_FLAG_DAX		19	/* device supports DAX */
 #define QUEUE_FLAG_STATS	20	/* track IO start and completion times */
 #define QUEUE_FLAG_POLL_STATS	21	/* collecting stats for hybrid polling */
@@ -621,6 +621,7 @@ struct request_queue {
 #define QUEUE_FLAG_RQ_ALLOC_TIME 27	/* record rq->alloc_time_ns */
 #define QUEUE_FLAG_HCTX_ACTIVE	28	/* at least one blk-mq hctx is active */
 #define QUEUE_FLAG_NOWAIT       29	/* device supports NOWAIT */
+#define QUEUE_FLAG_FUA_ENABLED	30	/* FUA writes are enabled */
 
 #define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
 				 (1 << QUEUE_FLAG_SAME_COMP) |		\
@@ -664,7 +665,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 			     REQ_FAILFAST_DRIVER))
 #define blk_queue_quiesced(q)	test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags)
 #define blk_queue_pm_only(q)	atomic_read(&(q)->pm_only)
-#define blk_queue_fua(q)	test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)
+#define blk_queue_fua(q)	test_bit(QUEUE_FLAG_FUA_ENABLED, &(q)->queue_flags)
 #define blk_queue_registered(q)	test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
 #define blk_queue_nowait(q)	test_bit(QUEUE_FLAG_NOWAIT, &(q)->queue_flags)