md: set md-specific flags for all queue limits

The md driver wants to enforce a number of flags for all devices, even
when not inheriting them from the underlying devices.  To make sure these
flags survive the queue_limits_set calls that md uses to update the
queue limits without deriving them form the previous limits add a new
md_init_stacking_limits helper that calls blk_set_stacking_limits and sets
these flags.

Fixes: 1122c0c ("block: move cache control settings out of queue->flags")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240626142637.300624-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

drivers/md/md.c

@@ -5853,6 +5853,14 @@ static void mddev_delayed_delete(struct work_struct *ws)
 	kobject_put(&mddev->kobj);
 }
 
+void md_init_stacking_limits(struct queue_limits *lim)
+{
+	blk_set_stacking_limits(lim);
+	lim->features = BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA |
+			BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT;
+}
+EXPORT_SYMBOL_GPL(md_init_stacking_limits);
+
 struct mddev *md_alloc(dev_t dev, char *name)
 {
 	/*
@@ -5871,10 +5879,6 @@ struct mddev *md_alloc(dev_t dev, char *name)
 	int shift;
 	int unit;
 	int error;
-	struct queue_limits lim = {
-		.features		= BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA |
-					  BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT,
-	};
 
 	/*
 	 * Wait for any previous instance of this device to be completely
@@ -5914,7 +5918,7 @@ struct mddev *md_alloc(dev_t dev, char *name)
 		 */
 		mddev->hold_active = UNTIL_STOP;
 
-	disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
+	disk = blk_alloc_disk(NULL, NUMA_NO_NODE);
 	if (IS_ERR(disk)) {
 		error = PTR_ERR(disk);
 		goto out_free_mddev;

drivers/md/md.h

@@ -893,6 +893,7 @@ extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 
 extern int mddev_init(struct mddev *mddev);
 extern void mddev_destroy(struct mddev *mddev);
+void md_init_stacking_limits(struct queue_limits *lim);
 struct mddev *md_alloc(dev_t dev, char *name);
 void mddev_put(struct mddev *mddev);
 extern int md_run(struct mddev *mddev);

drivers/md/raid0.c

@@ -379,7 +379,7 @@ static int raid0_set_limits(struct mddev *mddev)
 	struct queue_limits lim;
 	int err;
 
-	blk_set_stacking_limits(&lim);
+	md_init_stacking_limits(&lim);
 	lim.max_hw_sectors = mddev->chunk_sectors;
 	lim.max_write_zeroes_sectors = mddev->chunk_sectors;
 	lim.io_min = mddev->chunk_sectors << 9;

drivers/md/raid1.c

@@ -3194,7 +3194,7 @@ static int raid1_set_limits(struct mddev *mddev)
 	struct queue_limits lim;
 	int err;
 
-	blk_set_stacking_limits(&lim);
+	md_init_stacking_limits(&lim);
 	lim.max_write_zeroes_sectors = 0;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err) {

drivers/md/raid10.c

@@ -3974,7 +3974,7 @@ static int raid10_set_queue_limits(struct mddev *mddev)
 	struct queue_limits lim;
 	int err;
 
-	blk_set_stacking_limits(&lim);
+	md_init_stacking_limits(&lim);
 	lim.max_write_zeroes_sectors = 0;
 	lim.io_min = mddev->chunk_sectors << 9;
 	lim.io_opt = lim.io_min * raid10_nr_stripes(conf);

drivers/md/raid5.c

@@ -7708,7 +7708,7 @@ static int raid5_set_limits(struct mddev *mddev)
 	 */
 	stripe = roundup_pow_of_two(data_disks * (mddev->chunk_sectors << 9));
 
-	blk_set_stacking_limits(&lim);
+	md_init_stacking_limits(&lim);
 	lim.io_min = mddev->chunk_sectors << 9;
 	lim.io_opt = lim.io_min * (conf->raid_disks - conf->max_degraded);
 	lim.features |= BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE;