[PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.

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* [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
@ 2026-04-29  9:41 Li kunyu
  2026-05-02 23:34 ` kernel test robot
  2026-05-03  0:29 ` kernel test robot
  0 siblings, 2 replies; 6+ messages in thread
From: Li kunyu @ 2026-04-29  9:41 UTC (permalink / raw)
  To: axboe, tj, josef; +Cc: linux-block, linux-kernel, Li kunyu

Signed-off-by: Li kunyu <likunyu10@163.com>
---
 block/bio.c               |  2 ++
 block/blk-iolatency.c     | 34 ++++++++++++++++++++++++++++++++++
 block/blk-merge.c         |  7 ++++++-
 block/blk-rq-qos.h        | 11 +++++++++++
 include/linux/blk_types.h |  2 ++
 5 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index b8972dba68a0..7740701afc7f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1733,6 +1733,8 @@ static inline bool bio_remaining_done(struct bio *bio)
 		return true;
 	}
 
+	rq_qos_done_split_bio(bio);
+
 	return false;
 }
 
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 53e8dd2dfa8a..ba5870bf14c5 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -632,6 +632,39 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 	}
 }
 
+static void blkcg_iolatency_done_split_bio(struct rq_qos *rqos, struct bio *bio)
+{
+	struct blkcg_gq *blkg;
+	struct rq_wait *rqw;
+	struct iolatency_grp *iolat;
+	int inflight = 0;
+
+	blkg = bio->bi_blkg;
+	if (!blkg || !bio_flagged(bio, BIO_QOS_CHAIN_CHILD))
+		return;
+
+	iolat = blkg_to_lat(bio->bi_blkg);
+	if (!iolat)
+		return;
+
+	if (!iolat->blkiolat->enabled)
+		return;
+
+	while (blkg && blkg->parent) {
+		iolat = blkg_to_lat(blkg);
+		if (!iolat) {
+			blkg = blkg->parent;
+			continue;
+		}
+		rqw = &iolat->rq_wait;
+
+		inflight = atomic_dec_return(&rqw->inflight);
+		WARN_ON_ONCE(inflight < 0);
+
+		blkg = blkg->parent;
+	}
+}
+
 static void blkcg_iolatency_exit(struct rq_qos *rqos)
 {
 	struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
@@ -645,6 +678,7 @@ static void blkcg_iolatency_exit(struct rq_qos *rqos)
 static const struct rq_qos_ops blkcg_iolatency_ops = {
 	.throttle = blkcg_iolatency_throttle,
 	.done_bio = blkcg_iolatency_done_bio,
+	.done_split_bio = blkcg_iolatency_done_split_bio,
 	.exit = blkcg_iolatency_exit,
 };
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index fcf09325b22e..c236f9b34044 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -151,8 +151,13 @@ static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
 	if (split_sectors) {
 		bio = bio_submit_split_bioset(bio, split_sectors,
 				&bio->bi_bdev->bd_disk->bio_split);
-		if (bio)
+		if (bio) {
 			bio->bi_opf |= REQ_NOMERGE;
+			/* Fix the issue where the inflight statistics
+			 * of the chained bio in the QoS are incorrect.
+			 */
+			bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
+		}
 	}
 
 	return bio;
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index a747a504fe42..496a27b9d412 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -45,6 +45,7 @@ struct rq_qos_ops {
 	void (*cleanup)(struct rq_qos *, struct bio *);
 	void (*queue_depth_changed)(struct rq_qos *);
 	void (*exit)(struct rq_qos *);
+	void (*done_split_bio)(struct rq_qos *, struct bio *);
 	const struct blk_mq_debugfs_attr *debugfs_attrs;
 };
 
@@ -108,6 +109,7 @@ void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
 void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
+void __rq_qos_done_split_bio(struct rq_qos *rqos, struct bio *bio);
 void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
 
 static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
@@ -157,6 +159,15 @@ static inline void rq_qos_done_bio(struct bio *bio)
 		__rq_qos_done_bio(q->rq_qos, bio);
 }
 
+static inline void rq_qos_done_split_bio(struct bio *bio)
+{
+	if (bio->bi_bdev && bio_flagged(bio, BIO_QOS_CHAIN_CHILD)) {
+		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+		if (q->rq_qos)
+			__rq_qos_done_split_bio(q->rq_qos, bio);
+	}
+}
+
 static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
 {
 	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 8808ee76e73c..63fee89ecc14 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -322,6 +322,8 @@ enum {
 	BIO_REMAPPED,
 	BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */
 	BIO_EMULATES_ZONE_APPEND, /* bio emulates a zone append operation */
+	BIO_QOS_CHAIN_CHILD,    /* chained bio child, used for segmenting out
+				* the bio */
 	BIO_FLAG_LAST
 };
 
-- 
2.47.3


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
  2026-04-29  9:41 [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project Li kunyu
@ 2026-05-02 23:34 ` kernel test robot
  2026-05-03  0:29 ` kernel test robot
  1 sibling, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-05-02 23:34 UTC (permalink / raw)
  To: Li kunyu, axboe, tj, josef
  Cc: oe-kbuild-all, linux-block, linux-kernel, Li kunyu

Hi Li,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe/for-next]
[also build test ERROR on linus/master v7.1-rc1 next-20260430]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Li-kunyu/block-blk-iolatency-Add-the-processing-flow-of-the-chained-bio-in-the-QoS-and-define-the-related-types-to-solve-the-prob/20260502-071718
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link:    https://lore.kernel.org/r/20260429094148.2394-1-likunyu10%40163.com
patch subject: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20260503/202605030725.SpXiNjpU-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260503/202605030725.SpXiNjpU-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605030725.SpXiNjpU-lkp@intel.com/

All errors (new ones prefixed by >>):

   block/blk-merge.c: In function 'bio_submit_split':
>> block/blk-merge.c:159:38: error: 'split' undeclared (first use in this function); did you mean 'sg_split'?
     159 |                         bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
         |                                      ^~~~~
         |                                      sg_split
   block/blk-merge.c:159:38: note: each undeclared identifier is reported only once for each function it appears in

vim +159 block/blk-merge.c

   142	
   143	static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
   144	{
   145		if (unlikely(split_sectors < 0)) {
   146			bio->bi_status = errno_to_blk_status(split_sectors);
   147			bio_endio(bio);
   148			return NULL;
   149		}
   150	
   151		if (split_sectors) {
   152			bio = bio_submit_split_bioset(bio, split_sectors,
   153					&bio->bi_bdev->bd_disk->bio_split);
   154			if (bio) {
   155				bio->bi_opf |= REQ_NOMERGE;
   156				/* Fix the issue where the inflight statistics
   157				 * of the chained bio in the QoS are incorrect.
   158				 */
 > 159				bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
   160			}
   161		}
   162	
   163		return bio;
   164	}
   165	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
  2026-04-29  9:41 [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project Li kunyu
  2026-05-02 23:34 ` kernel test robot
@ 2026-05-03  0:29 ` kernel test robot
  1 sibling, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-05-03  0:29 UTC (permalink / raw)
  To: Li kunyu, axboe, tj, josef
  Cc: llvm, oe-kbuild-all, linux-block, linux-kernel, Li kunyu

Hi Li,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe/for-next]
[also build test ERROR on linus/master v7.1-rc1 next-20260430]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Li-kunyu/block-blk-iolatency-Add-the-processing-flow-of-the-chained-bio-in-the-QoS-and-define-the-related-types-to-solve-the-prob/20260502-071718
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link:    https://lore.kernel.org/r/20260429094148.2394-1-likunyu10%40163.com
patch subject: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20260503/202605030844.RgfP9Jsd-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 5bac06718f502014fade905512f1d26d578a18f3)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260503/202605030844.RgfP9Jsd-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605030844.RgfP9Jsd-lkp@intel.com/

All errors (new ones prefixed by >>):

>> block/blk-merge.c:159:17: error: use of undeclared identifier 'split'
     159 |                         bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
         |                                      ^~~~~
   1 error generated.

vim +/split +159 block/blk-merge.c

   142	
   143	static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
   144	{
   145		if (unlikely(split_sectors < 0)) {
   146			bio->bi_status = errno_to_blk_status(split_sectors);
   147			bio_endio(bio);
   148			return NULL;
   149		}
   150	
   151		if (split_sectors) {
   152			bio = bio_submit_split_bioset(bio, split_sectors,
   153					&bio->bi_bdev->bd_disk->bio_split);
   154			if (bio) {
   155				bio->bi_opf |= REQ_NOMERGE;
   156				/* Fix the issue where the inflight statistics
   157				 * of the chained bio in the QoS are incorrect.
   158				 */
 > 159				bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
   160			}
   161		}
   162	
   163		return bio;
   164	}
   165	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
@ 2026-04-29  9:29 Li kunyu
  2026-05-01 21:47 ` kernel test robot
  2026-05-02  0:19 ` kernel test robot
  0 siblings, 2 replies; 6+ messages in thread
From: Li kunyu @ 2026-04-29  9:29 UTC (permalink / raw)
  To: axboe, tj, josef; +Cc: linux-block, linux-kernel, Li kunyu

Signed-off-by: Li kunyu <likunyu10@163.com>
---
 block/bio.c               |  2 ++
 block/blk-iolatency.c     | 34 ++++++++++++++++++++++++++++++++++
 block/blk-merge.c         |  6 +++++-
 block/blk-rq-qos.h        | 11 +++++++++++
 include/linux/blk_types.h |  2 ++
 5 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index b8972dba68a0..7740701afc7f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1733,6 +1733,8 @@ static inline bool bio_remaining_done(struct bio *bio)
 		return true;
 	}
 
+	rq_qos_done_split_bio(bio);
+
 	return false;
 }
 
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 53e8dd2dfa8a..ba5870bf14c5 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -632,6 +632,39 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 	}
 }
 
+static void blkcg_iolatency_done_split_bio(struct rq_qos *rqos, struct bio *bio)
+{
+	struct blkcg_gq *blkg;
+	struct rq_wait *rqw;
+	struct iolatency_grp *iolat;
+	int inflight = 0;
+
+	blkg = bio->bi_blkg;
+	if (!blkg || !bio_flagged(bio, BIO_QOS_CHAIN_CHILD))
+		return;
+
+	iolat = blkg_to_lat(bio->bi_blkg);
+	if (!iolat)
+		return;
+
+	if (!iolat->blkiolat->enabled)
+		return;
+
+	while (blkg && blkg->parent) {
+		iolat = blkg_to_lat(blkg);
+		if (!iolat) {
+			blkg = blkg->parent;
+			continue;
+		}
+		rqw = &iolat->rq_wait;
+
+		inflight = atomic_dec_return(&rqw->inflight);
+		WARN_ON_ONCE(inflight < 0);
+
+		blkg = blkg->parent;
+	}
+}
+
 static void blkcg_iolatency_exit(struct rq_qos *rqos)
 {
 	struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
@@ -645,6 +678,7 @@ static void blkcg_iolatency_exit(struct rq_qos *rqos)
 static const struct rq_qos_ops blkcg_iolatency_ops = {
 	.throttle = blkcg_iolatency_throttle,
 	.done_bio = blkcg_iolatency_done_bio,
+	.done_split_bio = blkcg_iolatency_done_split_bio,
 	.exit = blkcg_iolatency_exit,
 };
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index fcf09325b22e..26373b9c02d3 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -151,8 +151,12 @@ static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
 	if (split_sectors) {
 		bio = bio_submit_split_bioset(bio, split_sectors,
 				&bio->bi_bdev->bd_disk->bio_split);
-		if (bio)
+		if (bio) {
 			bio->bi_opf |= REQ_NOMERGE;
+			/* Fix the issue where the inflight statistics
+			 * of the chained bio in the QoS are incorrect.
+			 */
+			bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
 	}
 
 	return bio;
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index a747a504fe42..496a27b9d412 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -45,6 +45,7 @@ struct rq_qos_ops {
 	void (*cleanup)(struct rq_qos *, struct bio *);
 	void (*queue_depth_changed)(struct rq_qos *);
 	void (*exit)(struct rq_qos *);
+	void (*done_split_bio)(struct rq_qos *, struct bio *);
 	const struct blk_mq_debugfs_attr *debugfs_attrs;
 };
 
@@ -108,6 +109,7 @@ void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
 void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
+void __rq_qos_done_split_bio(struct rq_qos *rqos, struct bio *bio);
 void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
 
 static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
@@ -157,6 +159,15 @@ static inline void rq_qos_done_bio(struct bio *bio)
 		__rq_qos_done_bio(q->rq_qos, bio);
 }
 
+static inline void rq_qos_done_split_bio(struct bio *bio)
+{
+	if (bio->bi_bdev && bio_flagged(bio, BIO_QOS_CHAIN_CHILD)) {
+		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+		if (q->rq_qos)
+			__rq_qos_done_split_bio(q->rq_qos, bio);
+	}
+}
+
 static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
 {
 	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 8808ee76e73c..63fee89ecc14 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -322,6 +322,8 @@ enum {
 	BIO_REMAPPED,
 	BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */
 	BIO_EMULATES_ZONE_APPEND, /* bio emulates a zone append operation */
+	BIO_QOS_CHAIN_CHILD,    /* chained bio child, used for segmenting out
+				* the bio */
 	BIO_FLAG_LAST
 };
 
-- 
2.47.3


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
  2026-04-29  9:29 Li kunyu
@ 2026-05-01 21:47 ` kernel test robot
  2026-05-02  0:19 ` kernel test robot
  1 sibling, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-05-01 21:47 UTC (permalink / raw)
  To: Li kunyu, axboe, tj, josef
  Cc: oe-kbuild-all, linux-block, linux-kernel, Li kunyu

Hi Li,

kernel test robot noticed the following build warnings:

[auto build test WARNING on axboe/for-next]
[also build test WARNING on next-20260430]
[cannot apply to linus/master v6.16-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Li-kunyu/block-blk-iolatency-Add-the-processing-flow-of-the-chained-bio-in-the-QoS-and-define-the-related-types-to-solve-the-prob/20260501-153918
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link:    https://lore.kernel.org/r/20260429092920.2124-1-likunyu10%40163.com
patch subject: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260501/202605012326.wuozpBQs-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260501/202605012326.wuozpBQs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605012326.wuozpBQs-lkp@intel.com/

All warnings (new ones prefixed by >>):

   include/linux/export.h:89:41: note: in expansion of macro '_EXPORT_SYMBOL'
      89 | #define EXPORT_SYMBOL(sym)              _EXPORT_SYMBOL(sym, "")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:491:1: note: in expansion of macro 'EXPORT_SYMBOL'
     491 | EXPORT_SYMBOL(bio_split_to_limits);
         | ^~~~~~~~~~~~~
   block/blk-merge.c:485:13: note: previous definition of 'bio_split_to_limits' with type 'struct bio *(struct bio *)'
     485 | struct bio *bio_split_to_limits(struct bio *bio)
         |             ^~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:526:28: error: invalid storage class for function 'blk_rq_get_max_sectors'
     526 | static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
         |                            ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:548:19: error: invalid storage class for function 'll_new_hw_segment'
     548 | static inline int ll_new_hw_segment(struct request *req, struct bio *bio,
         |                   ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:597:12: error: invalid storage class for function 'll_front_merge_fn'
     597 | static int ll_front_merge_fn(struct request *req, struct bio *bio,
         |            ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:616:13: error: invalid storage class for function 'req_attempt_discard_merge'
     616 | static bool req_attempt_discard_merge(struct request_queue *q, struct request *req,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:634:12: error: invalid storage class for function 'll_merge_requests_fn'
     634 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
         |            ^~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:677:13: error: invalid storage class for function 'blk_rq_set_mixed_merge'
     677 | static void blk_rq_set_mixed_merge(struct request *rq)
         |             ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:698:25: error: invalid storage class for function 'bio_failfast'
     698 | static inline blk_opf_t bio_failfast(const struct bio *bio)
         |                         ^~~~~~~~~~~~
   block/blk-merge.c:711:20: error: invalid storage class for function 'blk_update_mixed_merge'
     711 | static inline void blk_update_mixed_merge(struct request *req,
         |                    ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:725:13: error: invalid storage class for function 'blk_account_io_merge_request'
     725 | static void blk_account_io_merge_request(struct request *req)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:736:23: error: invalid storage class for function 'blk_try_req_merge'
     736 | static enum elv_merge blk_try_req_merge(struct request *req,
         |                       ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:747:13: error: invalid storage class for function 'blk_atomic_write_mergeable_rq_bio'
     747 | static bool blk_atomic_write_mergeable_rq_bio(struct request *rq,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:753:13: error: invalid storage class for function 'blk_atomic_write_mergeable_rqs'
     753 | static bool blk_atomic_write_mergeable_rqs(struct request *rq,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:781:24: error: invalid storage class for function 'attempt_merge'
     781 | static struct request *attempt_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~
   block/blk-merge.c:869:24: error: invalid storage class for function 'attempt_back_merge'
     869 | static struct request *attempt_back_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~~~~~~
   block/blk-merge.c:880:24: error: invalid storage class for function 'attempt_front_merge'
     880 | static struct request *attempt_front_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:939:13: error: invalid storage class for function 'blk_account_io_merge_bio'
     939 | static void blk_account_io_merge_bio(struct request *req)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:979:30: error: invalid storage class for function 'bio_attempt_front_merge'
     979 | static enum bio_merge_status bio_attempt_front_merge(struct request *req,
         |                              ^~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1017:30: error: invalid storage class for function 'bio_attempt_discard_merge'
    1017 | static enum bio_merge_status bio_attempt_discard_merge(struct request_queue *q,
         |                              ^~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1042:30: error: invalid storage class for function 'blk_attempt_bio_merge'
    1042 | static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
         |                              ^~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1143:19: error: non-static declaration of 'blk_bio_list_merge' follows static declaration
    1143 | EXPORT_SYMBOL_GPL(blk_bio_list_merge);
         |                   ^~~~~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:90:41: note: in expansion of macro '_EXPORT_SYMBOL'
      90 | #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:1143:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    1143 | EXPORT_SYMBOL_GPL(blk_bio_list_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:1120:6: note: previous definition of 'blk_bio_list_merge' with type 'bool(struct request_queue *, struct list_head *, struct bio *, unsigned int)' {aka '_Bool(struct request_queue *, struct list_head *, struct bio *, unsigned int)'}
    1120 | bool blk_bio_list_merge(struct request_queue *q, struct list_head *list,
         |      ^~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1175:19: error: non-static declaration of 'blk_mq_sched_try_merge' follows static declaration
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         |                   ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:90:41: note: in expansion of macro '_EXPORT_SYMBOL'
      90 | #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:1175:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:1145:6: note: previous definition of 'blk_mq_sched_try_merge' with type 'bool(struct request_queue *, struct bio *, unsigned int,  struct request **)' {aka '_Bool(struct request_queue *, struct bio *, unsigned int,  struct request **)'}
    1145 | bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
         |      ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1175:1: error: expected declaration or statement at end of input
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c: At top level:
>> block/blk-merge.c:1089:6: warning: 'blk_attempt_plug_merge' defined but not used [-Wunused-function]
    1089 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
         |      ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:896:6: warning: 'blk_attempt_req_merge' defined but not used [-Wunused-function]
     896 | bool blk_attempt_req_merge(struct request_queue *q, struct request *rq,
         |      ^~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:493:14: warning: 'blk_recalc_rq_segments' defined but not used [-Wunused-function]
     493 | unsigned int blk_recalc_rq_segments(struct request *rq)
         |              ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:454:13: warning: 'bio_split_write_zeroes' defined but not used [-Wunused-function]
     454 | struct bio *bio_split_write_zeroes(struct bio *bio,
         |             ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:442:13: warning: 'bio_split_zone_append' defined but not used [-Wunused-function]
     442 | struct bio *bio_split_zone_append(struct bio *bio,
         |             ^~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:427:13: warning: 'bio_split_rw' defined but not used [-Wunused-function]
     427 | struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
         |             ^~~~~~~~~~~~
>> block/blk-merge.c:201:13: warning: 'bio_split_discard' defined but not used [-Wunused-function]
     201 | struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
         |             ^~~~~~~~~~~~~~~~~


vim +/blk_attempt_plug_merge +1089 block/blk-merge.c

5e84ea3a9c662d Jens Axboe         2011-03-21   890  
fd2ef39cc9a6b9 Jan Kara           2021-06-23   891  /*
fd2ef39cc9a6b9 Jan Kara           2021-06-23   892   * Try to merge 'next' into 'rq'. Return true if the merge happened, false
fd2ef39cc9a6b9 Jan Kara           2021-06-23   893   * otherwise. The caller is responsible for freeing 'next' if the merge
fd2ef39cc9a6b9 Jan Kara           2021-06-23   894   * happened.
fd2ef39cc9a6b9 Jan Kara           2021-06-23   895   */
fd2ef39cc9a6b9 Jan Kara           2021-06-23  @896  bool blk_attempt_req_merge(struct request_queue *q, struct request *rq,
5e84ea3a9c662d Jens Axboe         2011-03-21   897  			   struct request *next)
5e84ea3a9c662d Jens Axboe         2011-03-21   898  {
fd2ef39cc9a6b9 Jan Kara           2021-06-23   899  	return attempt_merge(q, rq, next);
5e84ea3a9c662d Jens Axboe         2011-03-21   900  }
050c8ea80e3e90 Tejun Heo          2012-02-08   901  
050c8ea80e3e90 Tejun Heo          2012-02-08   902  bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
050c8ea80e3e90 Tejun Heo          2012-02-08   903  {
e2a60da74fc821 Martin K. Petersen 2012-09-18   904  	if (!rq_mergeable(rq) || !bio_mergeable(bio))
050c8ea80e3e90 Tejun Heo          2012-02-08   905  		return false;
050c8ea80e3e90 Tejun Heo          2012-02-08   906  
288dab8a35a0bd Christoph Hellwig  2016-06-09   907  	if (req_op(rq) != bio_op(bio))
f31dc1cd490539 Martin K. Petersen 2012-09-18   908  		return false;
f31dc1cd490539 Martin K. Petersen 2012-09-18   909  
6b2b04590b51aa Tejun Heo          2022-03-14   910  	if (!blk_cgroup_mergeable(rq, bio))
6b2b04590b51aa Tejun Heo          2022-03-14   911  		return false;
4eaf99beadcefb Martin K. Petersen 2014-09-26   912  	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
050c8ea80e3e90 Tejun Heo          2012-02-08   913  		return false;
a892c8d52c0228 Satya Tangirala    2020-05-14   914  	if (!bio_crypt_rq_ctx_compatible(rq, bio))
a892c8d52c0228 Satya Tangirala    2020-05-14   915  		return false;
61952bb73486ff Christoph Hellwig  2024-11-12   916  	if (rq->bio->bi_write_hint != bio->bi_write_hint)
449813515d3e5e Bart Van Assche    2024-02-02   917  		return false;
5006f85ea23ea0 Christoph Hellwig  2025-05-06   918  	if (rq->bio->bi_write_stream != bio->bi_write_stream)
5006f85ea23ea0 Christoph Hellwig  2025-05-06   919  		return false;
6975c1a486a404 Christoph Hellwig  2024-11-12   920  	if (rq->bio->bi_ioprio != bio->bi_ioprio)
668ffc03418bc7 Damien Le Moal     2018-11-20   921  		return false;
9da3d1e912f395 John Garry         2024-06-20   922  	if (blk_atomic_write_mergeable_rq_bio(rq, bio) == false)
9da3d1e912f395 John Garry         2024-06-20   923  		return false;
9da3d1e912f395 John Garry         2024-06-20   924  
050c8ea80e3e90 Tejun Heo          2012-02-08   925  	return true;
050c8ea80e3e90 Tejun Heo          2012-02-08   926  }
050c8ea80e3e90 Tejun Heo          2012-02-08   927  
34fe7c05400663 Christoph Hellwig  2017-02-08   928  enum elv_merge blk_try_merge(struct request *rq, struct bio *bio)
050c8ea80e3e90 Tejun Heo          2012-02-08   929  {
caebce24f6a7f8 Jens Axboe         2025-11-18   930  	if (blk_discard_mergable(rq))
caebce24f6a7f8 Jens Axboe         2025-11-18   931  		return ELEVATOR_DISCARD_MERGE;
caebce24f6a7f8 Jens Axboe         2025-11-18   932  	else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector)
050c8ea80e3e90 Tejun Heo          2012-02-08   933  		return ELEVATOR_BACK_MERGE;
4f024f3797c43c Kent Overstreet    2013-10-11   934  	else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector)
050c8ea80e3e90 Tejun Heo          2012-02-08   935  		return ELEVATOR_FRONT_MERGE;
050c8ea80e3e90 Tejun Heo          2012-02-08   936  	return ELEVATOR_NO_MERGE;
050c8ea80e3e90 Tejun Heo          2012-02-08   937  }
8e756373d7c8eb Baolin Wang        2020-08-28   938  
8e756373d7c8eb Baolin Wang        2020-08-28   939  static void blk_account_io_merge_bio(struct request *req)
8e756373d7c8eb Baolin Wang        2020-08-28   940  {
e3569ecae44daa Jens Axboe         2024-10-03   941  	if (req->rq_flags & RQF_IO_STAT) {
8e756373d7c8eb Baolin Wang        2020-08-28   942  		part_stat_lock();
8e756373d7c8eb Baolin Wang        2020-08-28   943  		part_stat_inc(req->part, merges[op_stat_group(req_op(req))]);
8e756373d7c8eb Baolin Wang        2020-08-28   944  		part_stat_unlock();
8e756373d7c8eb Baolin Wang        2020-08-28   945  	}
e3569ecae44daa Jens Axboe         2024-10-03   946  }
8e756373d7c8eb Baolin Wang        2020-08-28   947  
dd850ff3eee428 Damien Le Moal     2024-04-08   948  enum bio_merge_status bio_attempt_back_merge(struct request *req,
eda5cc997abd21 Christoph Hellwig  2020-10-06   949  		struct bio *bio, unsigned int nr_segs)
8e756373d7c8eb Baolin Wang        2020-08-28   950  {
3ce6a115980c01 Ming Lei           2023-02-09   951  	const blk_opf_t ff = bio_failfast(bio);
8e756373d7c8eb Baolin Wang        2020-08-28   952  
8e756373d7c8eb Baolin Wang        2020-08-28   953  	if (!ll_back_merge_fn(req, bio, nr_segs))
7d7ca7c5269bec Baolin Wang        2020-08-28   954  		return BIO_MERGE_FAILED;
8e756373d7c8eb Baolin Wang        2020-08-28   955  
e8a676d61c07ec Christoph Hellwig  2020-12-03   956  	trace_block_bio_backmerge(bio);
8e756373d7c8eb Baolin Wang        2020-08-28   957  	rq_qos_merge(req->q, req, bio);
8e756373d7c8eb Baolin Wang        2020-08-28   958  
8e756373d7c8eb Baolin Wang        2020-08-28   959  	if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
8e756373d7c8eb Baolin Wang        2020-08-28   960  		blk_rq_set_mixed_merge(req);
8e756373d7c8eb Baolin Wang        2020-08-28   961  
3ce6a115980c01 Ming Lei           2023-02-09   962  	blk_update_mixed_merge(req, bio, false);
3ce6a115980c01 Ming Lei           2023-02-09   963  
dd291d77cc90eb Damien Le Moal     2024-04-08   964  	if (req->rq_flags & RQF_ZONE_WRITE_PLUGGING)
dd291d77cc90eb Damien Le Moal     2024-04-08   965  		blk_zone_write_plug_bio_merged(bio);
dd291d77cc90eb Damien Le Moal     2024-04-08   966  
2f6b2565d43cdb Keith Busch        2025-10-14   967  	req->phys_gap_bit = bio_seg_gap(req->q, req->biotail, bio,
2f6b2565d43cdb Keith Busch        2025-10-14   968  					req->phys_gap_bit);
8e756373d7c8eb Baolin Wang        2020-08-28   969  	req->biotail->bi_next = bio;
8e756373d7c8eb Baolin Wang        2020-08-28   970  	req->biotail = bio;
8e756373d7c8eb Baolin Wang        2020-08-28   971  	req->__data_len += bio->bi_iter.bi_size;
8e756373d7c8eb Baolin Wang        2020-08-28   972  
8e756373d7c8eb Baolin Wang        2020-08-28   973  	bio_crypt_free_ctx(bio);
8e756373d7c8eb Baolin Wang        2020-08-28   974  
8e756373d7c8eb Baolin Wang        2020-08-28   975  	blk_account_io_merge_bio(req);
7d7ca7c5269bec Baolin Wang        2020-08-28   976  	return BIO_MERGE_OK;
8e756373d7c8eb Baolin Wang        2020-08-28   977  }
8e756373d7c8eb Baolin Wang        2020-08-28   978  
eda5cc997abd21 Christoph Hellwig  2020-10-06   979  static enum bio_merge_status bio_attempt_front_merge(struct request *req,
eda5cc997abd21 Christoph Hellwig  2020-10-06   980  		struct bio *bio, unsigned int nr_segs)
8e756373d7c8eb Baolin Wang        2020-08-28   981  {
3ce6a115980c01 Ming Lei           2023-02-09   982  	const blk_opf_t ff = bio_failfast(bio);
8e756373d7c8eb Baolin Wang        2020-08-28   983  
dd291d77cc90eb Damien Le Moal     2024-04-08   984  	/*
dd291d77cc90eb Damien Le Moal     2024-04-08   985  	 * A front merge for writes to sequential zones of a zoned block device
dd291d77cc90eb Damien Le Moal     2024-04-08   986  	 * can happen only if the user submitted writes out of order. Do not
dd291d77cc90eb Damien Le Moal     2024-04-08   987  	 * merge such write to let it fail.
dd291d77cc90eb Damien Le Moal     2024-04-08   988  	 */
dd291d77cc90eb Damien Le Moal     2024-04-08   989  	if (req->rq_flags & RQF_ZONE_WRITE_PLUGGING)
dd291d77cc90eb Damien Le Moal     2024-04-08   990  		return BIO_MERGE_FAILED;
dd291d77cc90eb Damien Le Moal     2024-04-08   991  
8e756373d7c8eb Baolin Wang        2020-08-28   992  	if (!ll_front_merge_fn(req, bio, nr_segs))
7d7ca7c5269bec Baolin Wang        2020-08-28   993  		return BIO_MERGE_FAILED;
8e756373d7c8eb Baolin Wang        2020-08-28   994  
e8a676d61c07ec Christoph Hellwig  2020-12-03   995  	trace_block_bio_frontmerge(bio);
8e756373d7c8eb Baolin Wang        2020-08-28   996  	rq_qos_merge(req->q, req, bio);
8e756373d7c8eb Baolin Wang        2020-08-28   997  
8e756373d7c8eb Baolin Wang        2020-08-28   998  	if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
8e756373d7c8eb Baolin Wang        2020-08-28   999  		blk_rq_set_mixed_merge(req);
8e756373d7c8eb Baolin Wang        2020-08-28  1000  
3ce6a115980c01 Ming Lei           2023-02-09  1001  	blk_update_mixed_merge(req, bio, true);
3ce6a115980c01 Ming Lei           2023-02-09  1002  
2f6b2565d43cdb Keith Busch        2025-10-14  1003  	req->phys_gap_bit = bio_seg_gap(req->q, bio, req->bio,
2f6b2565d43cdb Keith Busch        2025-10-14  1004  					req->phys_gap_bit);
8e756373d7c8eb Baolin Wang        2020-08-28  1005  	bio->bi_next = req->bio;
8e756373d7c8eb Baolin Wang        2020-08-28  1006  	req->bio = bio;
8e756373d7c8eb Baolin Wang        2020-08-28  1007  
8e756373d7c8eb Baolin Wang        2020-08-28  1008  	req->__sector = bio->bi_iter.bi_sector;
8e756373d7c8eb Baolin Wang        2020-08-28  1009  	req->__data_len += bio->bi_iter.bi_size;
8e756373d7c8eb Baolin Wang        2020-08-28  1010  
8e756373d7c8eb Baolin Wang        2020-08-28  1011  	bio_crypt_do_front_merge(req, bio);
8e756373d7c8eb Baolin Wang        2020-08-28  1012  
8e756373d7c8eb Baolin Wang        2020-08-28  1013  	blk_account_io_merge_bio(req);
7d7ca7c5269bec Baolin Wang        2020-08-28  1014  	return BIO_MERGE_OK;
8e756373d7c8eb Baolin Wang        2020-08-28  1015  }
8e756373d7c8eb Baolin Wang        2020-08-28  1016  
eda5cc997abd21 Christoph Hellwig  2020-10-06  1017  static enum bio_merge_status bio_attempt_discard_merge(struct request_queue *q,
eda5cc997abd21 Christoph Hellwig  2020-10-06  1018  		struct request *req, struct bio *bio)
8e756373d7c8eb Baolin Wang        2020-08-28  1019  {
8e756373d7c8eb Baolin Wang        2020-08-28  1020  	unsigned short segments = blk_rq_nr_discard_segments(req);
8e756373d7c8eb Baolin Wang        2020-08-28  1021  
8e756373d7c8eb Baolin Wang        2020-08-28  1022  	if (segments >= queue_max_discard_segments(q))
8e756373d7c8eb Baolin Wang        2020-08-28  1023  		goto no_merge;
8e756373d7c8eb Baolin Wang        2020-08-28  1024  	if (blk_rq_sectors(req) + bio_sectors(bio) >
8e756373d7c8eb Baolin Wang        2020-08-28  1025  	    blk_rq_get_max_sectors(req, blk_rq_pos(req)))
8e756373d7c8eb Baolin Wang        2020-08-28  1026  		goto no_merge;
8e756373d7c8eb Baolin Wang        2020-08-28  1027  
8e756373d7c8eb Baolin Wang        2020-08-28  1028  	rq_qos_merge(q, req, bio);
8e756373d7c8eb Baolin Wang        2020-08-28  1029  
8e756373d7c8eb Baolin Wang        2020-08-28  1030  	req->biotail->bi_next = bio;
8e756373d7c8eb Baolin Wang        2020-08-28  1031  	req->biotail = bio;
8e756373d7c8eb Baolin Wang        2020-08-28  1032  	req->__data_len += bio->bi_iter.bi_size;
8e756373d7c8eb Baolin Wang        2020-08-28  1033  	req->nr_phys_segments = segments + 1;
8e756373d7c8eb Baolin Wang        2020-08-28  1034  
8e756373d7c8eb Baolin Wang        2020-08-28  1035  	blk_account_io_merge_bio(req);
7d7ca7c5269bec Baolin Wang        2020-08-28  1036  	return BIO_MERGE_OK;
8e756373d7c8eb Baolin Wang        2020-08-28  1037  no_merge:
8e756373d7c8eb Baolin Wang        2020-08-28  1038  	req_set_nomerge(q, req);
7d7ca7c5269bec Baolin Wang        2020-08-28  1039  	return BIO_MERGE_FAILED;
7d7ca7c5269bec Baolin Wang        2020-08-28  1040  }
7d7ca7c5269bec Baolin Wang        2020-08-28  1041  
7d7ca7c5269bec Baolin Wang        2020-08-28  1042  static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
7d7ca7c5269bec Baolin Wang        2020-08-28  1043  						   struct request *rq,
7d7ca7c5269bec Baolin Wang        2020-08-28  1044  						   struct bio *bio,
7d7ca7c5269bec Baolin Wang        2020-08-28  1045  						   unsigned int nr_segs,
7d7ca7c5269bec Baolin Wang        2020-08-28  1046  						   bool sched_allow_merge)
7d7ca7c5269bec Baolin Wang        2020-08-28  1047  {
7d7ca7c5269bec Baolin Wang        2020-08-28  1048  	if (!blk_rq_merge_ok(rq, bio))
7d7ca7c5269bec Baolin Wang        2020-08-28  1049  		return BIO_MERGE_NONE;
7d7ca7c5269bec Baolin Wang        2020-08-28  1050  
7d7ca7c5269bec Baolin Wang        2020-08-28  1051  	switch (blk_try_merge(rq, bio)) {
7d7ca7c5269bec Baolin Wang        2020-08-28  1052  	case ELEVATOR_BACK_MERGE:
265600b7b6e88f Baolin Wang        2020-09-02  1053  		if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
7d7ca7c5269bec Baolin Wang        2020-08-28  1054  			return bio_attempt_back_merge(rq, bio, nr_segs);
7d7ca7c5269bec Baolin Wang        2020-08-28  1055  		break;
7d7ca7c5269bec Baolin Wang        2020-08-28  1056  	case ELEVATOR_FRONT_MERGE:
265600b7b6e88f Baolin Wang        2020-09-02  1057  		if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
7d7ca7c5269bec Baolin Wang        2020-08-28  1058  			return bio_attempt_front_merge(rq, bio, nr_segs);
7d7ca7c5269bec Baolin Wang        2020-08-28  1059  		break;
7d7ca7c5269bec Baolin Wang        2020-08-28  1060  	case ELEVATOR_DISCARD_MERGE:
7d7ca7c5269bec Baolin Wang        2020-08-28  1061  		return bio_attempt_discard_merge(q, rq, bio);
7d7ca7c5269bec Baolin Wang        2020-08-28  1062  	default:
7d7ca7c5269bec Baolin Wang        2020-08-28  1063  		return BIO_MERGE_NONE;
7d7ca7c5269bec Baolin Wang        2020-08-28  1064  	}
7d7ca7c5269bec Baolin Wang        2020-08-28  1065  
7d7ca7c5269bec Baolin Wang        2020-08-28  1066  	return BIO_MERGE_FAILED;
8e756373d7c8eb Baolin Wang        2020-08-28  1067  }
8e756373d7c8eb Baolin Wang        2020-08-28  1068  
8e756373d7c8eb Baolin Wang        2020-08-28  1069  /**
8e756373d7c8eb Baolin Wang        2020-08-28  1070   * blk_attempt_plug_merge - try to merge with %current's plugged list
8e756373d7c8eb Baolin Wang        2020-08-28  1071   * @q: request_queue new bio is being queued at
8e756373d7c8eb Baolin Wang        2020-08-28  1072   * @bio: new bio being queued
8e756373d7c8eb Baolin Wang        2020-08-28  1073   * @nr_segs: number of segments in @bio
87c037d11b83b9 Jens Axboe         2021-10-18  1074   * from the passed in @q already in the plug list
8e756373d7c8eb Baolin Wang        2020-08-28  1075   *
d38a9c04c0d563 Jens Axboe         2021-10-14  1076   * Determine whether @bio being queued on @q can be merged with the previous
d38a9c04c0d563 Jens Axboe         2021-10-14  1077   * request on %current's plugged list.  Returns %true if merge was successful,
8e756373d7c8eb Baolin Wang        2020-08-28  1078   * otherwise %false.
8e756373d7c8eb Baolin Wang        2020-08-28  1079   *
8e756373d7c8eb Baolin Wang        2020-08-28  1080   * Plugging coalesces IOs from the same issuer for the same purpose without
8e756373d7c8eb Baolin Wang        2020-08-28  1081   * going through @q->queue_lock.  As such it's more of an issuing mechanism
8e756373d7c8eb Baolin Wang        2020-08-28  1082   * than scheduling, and the request, while may have elvpriv data, is not
8e756373d7c8eb Baolin Wang        2020-08-28  1083   * added on the elevator at this point.  In addition, we don't have
8e756373d7c8eb Baolin Wang        2020-08-28  1084   * reliable access to the elevator outside queue lock.  Only check basic
8e756373d7c8eb Baolin Wang        2020-08-28  1085   * merging parameters without querying the elevator.
8e756373d7c8eb Baolin Wang        2020-08-28  1086   *
8e756373d7c8eb Baolin Wang        2020-08-28  1087   * Caller must ensure !blk_queue_nomerges(q) beforehand.
8e756373d7c8eb Baolin Wang        2020-08-28  1088   */
8e756373d7c8eb Baolin Wang        2020-08-28 @1089  bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
0c5bcc92d94a8f Christoph Hellwig  2021-11-23  1090  		unsigned int nr_segs)
8e756373d7c8eb Baolin Wang        2020-08-28  1091  {
99a9476b27e895 Damien Le Moal     2024-04-08  1092  	struct blk_plug *plug = current->plug;
8e756373d7c8eb Baolin Wang        2020-08-28  1093  	struct request *rq;
8e756373d7c8eb Baolin Wang        2020-08-28  1094  
a3396b99990d8b Christoph Hellwig  2024-11-13  1095  	if (!plug || rq_list_empty(&plug->mq_list))
8e756373d7c8eb Baolin Wang        2020-08-28  1096  		return false;
8e756373d7c8eb Baolin Wang        2020-08-28  1097  
961296e89dc380 Jens Axboe         2025-06-11  1098  	rq = plug->mq_list.tail;
961296e89dc380 Jens Axboe         2025-06-11  1099  	if (rq->q == q)
961296e89dc380 Jens Axboe         2025-06-11  1100  		return blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
961296e89dc380 Jens Axboe         2025-06-11  1101  			BIO_MERGE_OK;
961296e89dc380 Jens Axboe         2025-06-11  1102  	else if (!plug->multiple_queues)
961296e89dc380 Jens Axboe         2025-06-11  1103  		return false;
961296e89dc380 Jens Axboe         2025-06-11  1104  
5b2050718d095c Jens Axboe         2022-03-11  1105  	rq_list_for_each(&plug->mq_list, rq) {
961296e89dc380 Jens Axboe         2025-06-11  1106  		if (rq->q != q)
961296e89dc380 Jens Axboe         2025-06-11  1107  			continue;
a1cb65377e7075 Ming Lei           2021-11-02  1108  		if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
a1cb65377e7075 Ming Lei           2021-11-02  1109  		    BIO_MERGE_OK)
8e756373d7c8eb Baolin Wang        2020-08-28  1110  			return true;
5b2050718d095c Jens Axboe         2022-03-11  1111  		break;
5b2050718d095c Jens Axboe         2022-03-11  1112  	}
8e756373d7c8eb Baolin Wang        2020-08-28  1113  	return false;
8e756373d7c8eb Baolin Wang        2020-08-28  1114  }
bdc6a287bc98e8 Baolin Wang        2020-08-28  1115  

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
  2026-04-29  9:29 Li kunyu
  2026-05-01 21:47 ` kernel test robot
@ 2026-05-02  0:19 ` kernel test robot
  1 sibling, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-05-02  0:19 UTC (permalink / raw)
  To: Li kunyu, axboe, tj, josef
  Cc: oe-kbuild-all, linux-block, linux-kernel, Li kunyu

Hi Li,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe/for-next]
[also build test ERROR on next-20260430]
[cannot apply to linus/master v6.16-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Li-kunyu/block-blk-iolatency-Add-the-processing-flow-of-the-chained-bio-in-the-QoS-and-define-the-related-types-to-solve-the-prob/20260501-153918
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link:    https://lore.kernel.org/r/20260429092920.2124-1-likunyu10%40163.com
patch subject: [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project.
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260502/202605020222.x7HELUvP-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260502/202605020222.x7HELUvP-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605020222.x7HELUvP-lkp@intel.com/

All errors (new ones prefixed by >>):

   block/blk-merge.c: In function 'bio_submit_split':
>> block/blk-merge.c:159:38: error: 'split' undeclared (first use in this function); did you mean 'sg_split'?
     159 |                         bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
         |                                      ^~~~~
         |                                      sg_split
   block/blk-merge.c:159:38: note: each undeclared identifier is reported only once for each function it appears in
>> block/blk-merge.c:165:20: error: invalid storage class for function '__bio_split_discard'
     165 | static struct bio *__bio_split_discard(struct bio *bio,
         |                    ^~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:214:28: error: invalid storage class for function 'blk_boundary_sectors'
     214 | static inline unsigned int blk_boundary_sectors(const struct queue_limits *lim,
         |                            ^~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:235:24: error: invalid storage class for function 'get_max_io_size'
     235 | static inline unsigned get_max_io_size(struct bio *bio,
         |                        ^~~~~~~~~~~~~~~
>> block/blk-merge.c:288:13: error: invalid storage class for function 'bvec_split_segs'
     288 | static bool bvec_split_segs(const struct queue_limits *lim,
         |             ^~~~~~~~~~~~~~~
>> block/blk-merge.c:314:21: error: invalid storage class for function 'bio_split_alignment'
     314 | static unsigned int bio_split_alignment(struct bio *bio,
         |                     ^~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:322:28: error: invalid storage class for function 'bvec_seg_gap'
     322 | static inline unsigned int bvec_seg_gap(struct bio_vec *bvprv,
         |                            ^~~~~~~~~~~~
   In file included from include/linux/linkage.h:7,
                    from include/linux/kernel.h:18,
                    from block/blk-merge.c:5:
>> block/blk-merge.c:425:19: error: non-static declaration of 'bio_split_io_at' follows static declaration
     425 | EXPORT_SYMBOL_GPL(bio_split_io_at);
         |                   ^~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:90:41: note: in expansion of macro '_EXPORT_SYMBOL'
      90 | #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:425:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
     425 | EXPORT_SYMBOL_GPL(bio_split_io_at);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:341:5: note: previous definition of 'bio_split_io_at' with type 'int(struct bio *, const struct queue_limits *, unsigned int *, unsigned int,  unsigned int)'
     341 | int bio_split_io_at(struct bio *bio, const struct queue_limits *lim,
         |     ^~~~~~~~~~~~~~~
>> block/blk-merge.c:491:15: error: non-static declaration of 'bio_split_to_limits' follows static declaration
     491 | EXPORT_SYMBOL(bio_split_to_limits);
         |               ^~~~~~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:89:41: note: in expansion of macro '_EXPORT_SYMBOL'
      89 | #define EXPORT_SYMBOL(sym)              _EXPORT_SYMBOL(sym, "")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:491:1: note: in expansion of macro 'EXPORT_SYMBOL'
     491 | EXPORT_SYMBOL(bio_split_to_limits);
         | ^~~~~~~~~~~~~
   block/blk-merge.c:485:13: note: previous definition of 'bio_split_to_limits' with type 'struct bio *(struct bio *)'
     485 | struct bio *bio_split_to_limits(struct bio *bio)
         |             ^~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:526:28: error: invalid storage class for function 'blk_rq_get_max_sectors'
     526 | static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
         |                            ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:548:19: error: invalid storage class for function 'll_new_hw_segment'
     548 | static inline int ll_new_hw_segment(struct request *req, struct bio *bio,
         |                   ^~~~~~~~~~~~~~~~~
>> block/blk-merge.c:597:12: error: invalid storage class for function 'll_front_merge_fn'
     597 | static int ll_front_merge_fn(struct request *req, struct bio *bio,
         |            ^~~~~~~~~~~~~~~~~
>> block/blk-merge.c:616:13: error: invalid storage class for function 'req_attempt_discard_merge'
     616 | static bool req_attempt_discard_merge(struct request_queue *q, struct request *req,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:634:12: error: invalid storage class for function 'll_merge_requests_fn'
     634 | static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
         |            ^~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:677:13: error: invalid storage class for function 'blk_rq_set_mixed_merge'
     677 | static void blk_rq_set_mixed_merge(struct request *rq)
         |             ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:698:25: error: invalid storage class for function 'bio_failfast'
     698 | static inline blk_opf_t bio_failfast(const struct bio *bio)
         |                         ^~~~~~~~~~~~
>> block/blk-merge.c:711:20: error: invalid storage class for function 'blk_update_mixed_merge'
     711 | static inline void blk_update_mixed_merge(struct request *req,
         |                    ^~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:725:13: error: invalid storage class for function 'blk_account_io_merge_request'
     725 | static void blk_account_io_merge_request(struct request *req)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> block/blk-merge.c:736:23: error: invalid storage class for function 'blk_try_req_merge'
     736 | static enum elv_merge blk_try_req_merge(struct request *req,
         |                       ^~~~~~~~~~~~~~~~~
>> block/blk-merge.c:747:13: error: invalid storage class for function 'blk_atomic_write_mergeable_rq_bio'
     747 | static bool blk_atomic_write_mergeable_rq_bio(struct request *rq,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:753:13: error: invalid storage class for function 'blk_atomic_write_mergeable_rqs'
     753 | static bool blk_atomic_write_mergeable_rqs(struct request *rq,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:781:24: error: invalid storage class for function 'attempt_merge'
     781 | static struct request *attempt_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~
   block/blk-merge.c:869:24: error: invalid storage class for function 'attempt_back_merge'
     869 | static struct request *attempt_back_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~~~~~~
   block/blk-merge.c:880:24: error: invalid storage class for function 'attempt_front_merge'
     880 | static struct request *attempt_front_merge(struct request_queue *q,
         |                        ^~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:939:13: error: invalid storage class for function 'blk_account_io_merge_bio'
     939 | static void blk_account_io_merge_bio(struct request *req)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:979:30: error: invalid storage class for function 'bio_attempt_front_merge'
     979 | static enum bio_merge_status bio_attempt_front_merge(struct request *req,
         |                              ^~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1017:30: error: invalid storage class for function 'bio_attempt_discard_merge'
    1017 | static enum bio_merge_status bio_attempt_discard_merge(struct request_queue *q,
         |                              ^~~~~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1042:30: error: invalid storage class for function 'blk_attempt_bio_merge'
    1042 | static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q,
         |                              ^~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1143:19: error: non-static declaration of 'blk_bio_list_merge' follows static declaration
    1143 | EXPORT_SYMBOL_GPL(blk_bio_list_merge);
         |                   ^~~~~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:90:41: note: in expansion of macro '_EXPORT_SYMBOL'
      90 | #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:1143:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    1143 | EXPORT_SYMBOL_GPL(blk_bio_list_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:1120:6: note: previous definition of 'blk_bio_list_merge' with type 'bool(struct request_queue *, struct list_head *, struct bio *, unsigned int)' {aka '_Bool(struct request_queue *, struct list_head *, struct bio *, unsigned int)'}
    1120 | bool blk_bio_list_merge(struct request_queue *q, struct list_head *list,
         |      ^~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1175:19: error: non-static declaration of 'blk_mq_sched_try_merge' follows static declaration
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         |                   ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/export.h:76:28: note: in definition of macro '__EXPORT_SYMBOL'
      76 |         extern typeof(sym) sym;                                 \
         |                            ^~~
   include/linux/export.h:90:41: note: in expansion of macro '_EXPORT_SYMBOL'
      90 | #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
         |                                         ^~~~~~~~~~~~~~
   block/blk-merge.c:1175:1: note: in expansion of macro 'EXPORT_SYMBOL_GPL'
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c:1145:6: note: previous definition of 'blk_mq_sched_try_merge' with type 'bool(struct request_queue *, struct bio *, unsigned int,  struct request **)' {aka '_Bool(struct request_queue *, struct bio *, unsigned int,  struct request **)'}
    1145 | bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
         |      ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:1175:1: error: expected declaration or statement at end of input
    1175 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
         | ^~~~~~~~~~~~~~~~~
   block/blk-merge.c: At top level:
   block/blk-merge.c:1089:6: warning: 'blk_attempt_plug_merge' defined but not used [-Wunused-function]
    1089 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
         |      ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:896:6: warning: 'blk_attempt_req_merge' defined but not used [-Wunused-function]
     896 | bool blk_attempt_req_merge(struct request_queue *q, struct request *rq,
         |      ^~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:493:14: warning: 'blk_recalc_rq_segments' defined but not used [-Wunused-function]
     493 | unsigned int blk_recalc_rq_segments(struct request *rq)
         |              ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:454:13: warning: 'bio_split_write_zeroes' defined but not used [-Wunused-function]
     454 | struct bio *bio_split_write_zeroes(struct bio *bio,
         |             ^~~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:442:13: warning: 'bio_split_zone_append' defined but not used [-Wunused-function]
     442 | struct bio *bio_split_zone_append(struct bio *bio,
         |             ^~~~~~~~~~~~~~~~~~~~~
   block/blk-merge.c:427:13: warning: 'bio_split_rw' defined but not used [-Wunused-function]
     427 | struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
         |             ^~~~~~~~~~~~
   block/blk-merge.c:201:13: warning: 'bio_split_discard' defined but not used [-Wunused-function]
     201 | struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
         |             ^~~~~~~~~~~~~~~~~


vim +159 block/blk-merge.c

   142	
   143	static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
   144	{
   145		if (unlikely(split_sectors < 0)) {
   146			bio->bi_status = errno_to_blk_status(split_sectors);
   147			bio_endio(bio);
   148			return NULL;
   149		}
   150	
   151		if (split_sectors) {
   152			bio = bio_submit_split_bioset(bio, split_sectors,
   153					&bio->bi_bdev->bd_disk->bio_split);
   154			if (bio) {
   155				bio->bi_opf |= REQ_NOMERGE;
   156				/* Fix the issue where the inflight statistics
   157				 * of the chained bio in the QoS are incorrect.
   158				 */
 > 159				bio_set_flag(split, BIO_QOS_CHAIN_CHILD);
   160		}
   161	
   162		return bio;
   163	}
   164	
 > 165	static struct bio *__bio_split_discard(struct bio *bio,
   166			const struct queue_limits *lim, unsigned *nsegs,
   167			unsigned int max_sectors)
   168	{
   169		unsigned int max_discard_sectors, granularity;
   170		sector_t tmp;
   171		unsigned split_sectors;
   172	
   173		*nsegs = 1;
   174	
   175		granularity = max(lim->discard_granularity >> 9, 1U);
   176	
   177		max_discard_sectors = min(max_sectors, bio_allowed_max_sectors(lim));
   178		max_discard_sectors -= max_discard_sectors % granularity;
   179		if (unlikely(!max_discard_sectors))
   180			return bio;
   181	
   182		if (bio_sectors(bio) <= max_discard_sectors)
   183			return bio;
   184	
   185		split_sectors = max_discard_sectors;
   186	
   187		/*
   188		 * If the next starting sector would be misaligned, stop the discard at
   189		 * the previous aligned sector.
   190		 */
   191		tmp = bio->bi_iter.bi_sector + split_sectors -
   192			((lim->discard_alignment >> 9) % granularity);
   193		tmp = sector_div(tmp, granularity);
   194	
   195		if (split_sectors > tmp)
   196			split_sectors -= tmp;
   197	
   198		return bio_submit_split(bio, split_sectors);
   199	}
   200	
   201	struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
   202			unsigned *nsegs)
   203	{
   204		unsigned int max_sectors;
   205	
   206		if (bio_op(bio) == REQ_OP_SECURE_ERASE)
   207			max_sectors = lim->max_secure_erase_sectors;
   208		else
   209			max_sectors = lim->max_discard_sectors;
   210	
   211		return __bio_split_discard(bio, lim, nsegs, max_sectors);
   212	}
   213	
 > 214	static inline unsigned int blk_boundary_sectors(const struct queue_limits *lim,
   215							bool is_atomic)
   216	{
   217		/*
   218		 * chunk_sectors must be a multiple of atomic_write_boundary_sectors if
   219		 * both non-zero.
   220		 */
   221		if (is_atomic && lim->atomic_write_boundary_sectors)
   222			return lim->atomic_write_boundary_sectors;
   223	
   224		return lim->chunk_sectors;
   225	}
   226	
   227	/*
   228	 * Return the maximum number of sectors from the start of a bio that may be
   229	 * submitted as a single request to a block device. If enough sectors remain,
   230	 * align the end to the physical block size. Otherwise align the end to the
   231	 * logical block size. This approach minimizes the number of non-aligned
   232	 * requests that are submitted to a block device if the start of a bio is not
   233	 * aligned to a physical block boundary.
   234	 */
 > 235	static inline unsigned get_max_io_size(struct bio *bio,
   236					       const struct queue_limits *lim)
   237	{
   238		unsigned pbs = lim->physical_block_size >> SECTOR_SHIFT;
   239		unsigned lbs = lim->logical_block_size >> SECTOR_SHIFT;
   240		bool is_atomic = bio->bi_opf & REQ_ATOMIC;
   241		unsigned boundary_sectors = blk_boundary_sectors(lim, is_atomic);
   242		unsigned max_sectors, start, end;
   243	
   244		/*
   245		 * We ignore lim->max_sectors for atomic writes because it may less
   246		 * than the actual bio size, which we cannot tolerate.
   247		 */
   248		if (bio_op(bio) == REQ_OP_WRITE_ZEROES)
   249			max_sectors = lim->max_write_zeroes_sectors;
   250		else if (is_atomic)
   251			max_sectors = lim->atomic_write_max_sectors;
   252		else
   253			max_sectors = lim->max_sectors;
   254	
   255		if (boundary_sectors) {
   256			max_sectors = min(max_sectors,
   257				blk_boundary_sectors_left(bio->bi_iter.bi_sector,
   258						      boundary_sectors));
   259		}
   260	
   261		start = bio->bi_iter.bi_sector & (pbs - 1);
   262		end = (start + max_sectors) & ~(pbs - 1);
   263		if (end > start)
   264			return end - start;
   265		return max_sectors & ~(lbs - 1);
   266	}
   267	
   268	/**
   269	 * bvec_split_segs - verify whether or not a bvec should be split in the middle
   270	 * @lim:      [in] queue limits to split based on
   271	 * @bv:       [in] bvec to examine
   272	 * @nsegs:    [in,out] Number of segments in the bio being built. Incremented
   273	 *            by the number of segments from @bv that may be appended to that
   274	 *            bio without exceeding @max_segs
   275	 * @bytes:    [in,out] Number of bytes in the bio being built. Incremented
   276	 *            by the number of bytes from @bv that may be appended to that
   277	 *            bio without exceeding @max_bytes
   278	 * @max_segs: [in] upper bound for *@nsegs
   279	 * @max_bytes: [in] upper bound for *@bytes
   280	 *
   281	 * When splitting a bio, it can happen that a bvec is encountered that is too
   282	 * big to fit in a single segment and hence that it has to be split in the
   283	 * middle. This function verifies whether or not that should happen. The value
   284	 * %true is returned if and only if appending the entire @bv to a bio with
   285	 * *@nsegs segments and *@sectors sectors would make that bio unacceptable for
   286	 * the block driver.
   287	 */
 > 288	static bool bvec_split_segs(const struct queue_limits *lim,
   289			const struct bio_vec *bv, unsigned *nsegs, unsigned *bytes,
   290			unsigned max_segs, unsigned max_bytes)
   291	{
   292		unsigned max_len = max_bytes - *bytes;
   293		unsigned len = min(bv->bv_len, max_len);
   294		unsigned total_len = 0;
   295		unsigned seg_size = 0;
   296	
   297		while (len && *nsegs < max_segs) {
   298			seg_size = get_max_segment_size(lim, bvec_phys(bv) + total_len, len);
   299	
   300			(*nsegs)++;
   301			total_len += seg_size;
   302			len -= seg_size;
   303	
   304			if ((bv->bv_offset + total_len) & lim->virt_boundary_mask)
   305				break;
   306		}
   307	
   308		*bytes += total_len;
   309	
   310		/* tell the caller to split the bvec if it is too big to fit */
   311		return len > 0 || bv->bv_len > max_len;
   312	}
   313	
 > 314	static unsigned int bio_split_alignment(struct bio *bio,
   315			const struct queue_limits *lim)
   316	{
   317		if (op_is_write(bio_op(bio)) && lim->zone_write_granularity)
   318			return lim->zone_write_granularity;
   319		return lim->logical_block_size;
   320	}
   321	
 > 322	static inline unsigned int bvec_seg_gap(struct bio_vec *bvprv,
   323						struct bio_vec *bv)
   324	{
   325		return bv->bv_offset | (bvprv->bv_offset + bvprv->bv_len);
   326	}
   327	

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2026-04-29  9:41 [PATCH] block/blk-iolatency: Add the processing flow of the chained bio in the QoS and define the related types to solve the problem of incorrect inflight processing in the QoS. The usage of the done_split_bio abstract function in the blk-iolatency project Li kunyu
2026-05-02 23:34 ` kernel test robot
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