block: Improve zone reset execution

There is no need to synchronously execute all REQ_OP_ZONE_RESET BIOs
necessary to reset a range of zones. Similarly to what is done for
discard BIOs in blk-lib.c, all zone reset BIOs can be chained and
executed asynchronously and a synchronous call done only for the last
BIO of the chain.

Modify blkdev_reset_zones() to operate similarly to
blkdev_issue_discard() using the next_bio() helper for chaining BIOs. To
avoid code duplication of that function in blk_zoned.c, rename
next_bio() into blk_next_bio() and declare it as a block internal
function in blk.h.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 24 insertions, 20 deletions

diff --git a/block/blk-lib.c b/block/blk-lib.c
index bbd44666f2b5..76f867ea9a9b 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -10,8 +10,7 @@
 
 #include "blk.h"
 
-static struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
-                gfp_t gfp)
+struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
 {
         struct bio *new = bio_alloc(gfp, nr_pages);
 
@@ -63,7 +62,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
                 end_sect = sector + req_sects;
 
-                bio = next_bio(bio, 0, gfp_mask);
+                bio = blk_next_bio(bio, 0, gfp_mask);
                 bio->bi_iter.bi_sector = sector;
                 bio_set_dev(bio, bdev);
                 bio_set_op_attrs(bio, op, 0);
@@ -165,7 +164,7 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
         max_write_same_sectors = UINT_MAX >> 9;
 
         while (nr_sects) {
-                bio = next_bio(bio, 1, gfp_mask);
+                bio = blk_next_bio(bio, 1, gfp_mask);
                 bio->bi_iter.bi_sector = sector;
                 bio_set_dev(bio, bdev);
                 bio->bi_vcnt = 1;
@@ -241,7 +240,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
                 return -EOPNOTSUPP;
 
         while (nr_sects) {
-                bio = next_bio(bio, 0, gfp_mask);
+                bio = blk_next_bio(bio, 0, gfp_mask);
                 bio->bi_iter.bi_sector = sector;
                 bio_set_dev(bio, bdev);
                 bio->bi_opf = REQ_OP_WRITE_ZEROES;
@@ -292,8 +291,8 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
                 return -EPERM;
 
         while (nr_sects != 0) {
-                bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
-                               gfp_mask);
+                bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
+                                   gfp_mask);
                 bio->bi_iter.bi_sector = sector;
                 bio_set_dev(bio, bdev);
                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index bb4ed69f917f..5d967fd39fbd 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -13,6 +13,8 @@
 #include <linux/rbtree.h>
 #include <linux/blkdev.h>
 
+#include "blk.h"
+
 static inline sector_t blk_zone_start(struct request_queue *q,
                                       sector_t sector)
 {
@@ -277,16 +279,17 @@ int blkdev_reset_zones(struct block_device *bdev,
         struct request_queue *q = bdev_get_queue(bdev);
         sector_t zone_sectors;
         sector_t end_sector = sector + nr_sectors;
-        struct bio *bio;
+        struct bio *bio = NULL;
+        struct blk_plug plug;
         int ret;
 
-        if (!q)
-                return -ENXIO;
-
         if (!blk_queue_is_zoned(q))
                 return -EOPNOTSUPP;
 
-        if (end_sector > bdev->bd_part->nr_sects)
+        if (bdev_read_only(bdev))
+                return -EPERM;
+
+        if (!nr_sectors || end_sector > bdev->bd_part->nr_sects)
                 /* Out of range */
                 return -EINVAL;
 
@@ -299,19 +302,14 @@ int blkdev_reset_zones(struct block_device *bdev,
             end_sector != bdev->bd_part->nr_sects)
                 return -EINVAL;
 
+        blk_start_plug(&plug);
         while (sector < end_sector) {
 
-                bio = bio_alloc(gfp_mask, 0);
+                bio = blk_next_bio(bio, 0, gfp_mask);
                 bio->bi_iter.bi_sector = sector;
                 bio_set_dev(bio, bdev);
                 bio_set_op_attrs(bio, REQ_OP_ZONE_RESET, 0);
 
-                ret = submit_bio_wait(bio);
-                bio_put(bio);
-
-                if (ret)
-                        return ret;
-
                 sector += zone_sectors;
 
                 /* This may take a while, so be nice to others */
@@ -319,7 +317,12 @@ int blkdev_reset_zones(struct block_device *bdev,
 
         }
 
-        return 0;
+        ret = submit_bio_wait(bio);
+        bio_put(bio);
+
+        blk_finish_plug(&plug);
+
+        return ret;
 }
 EXPORT_SYMBOL_GPL(blkdev_reset_zones);
 
diff --git a/block/blk.h b/block/blk.h
index 3d2aecba96a4..93574baaa6b8 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -488,4 +488,6 @@ extern int blk_iolatency_init(struct request_queue *q);
 static inline int blk_iolatency_init(struct request_queue *q) { return 0; }
 #endif
 
+struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
+
 #endif /* BLK_INTERNAL_H */