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submit_bh: Drop unnecessary return values and API users

PATCH Superseded Ritesh Harjani 3 participants 8 messages Jun 20, 2022 – Jun 21, 2022

Subsystems (3)
VFS Journalling layer for block devices (JBD2) NTFS filesystem

v2 of 3 Superseded Latest is v3 →

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Ritesh Harjani

author
#0 lore raw

v2 cover submit_bh: Drop unnecessary return values and API users

submit_bh/submit_bh_wbc are non-blocking functions which just submits the bio and returns. The caller of submit_bh/submit_bh_wbc needs to wait on buffer till I/O completion and then check buffer head's b_state field to know if there was any I/O error.

Hence there is no need for these functions to have any return type. Even now they always returns 0. Hence drop the return value and make their return type as void to avoid any confusion.

RFC -> PATCHv2
===============
1. Added Patch-2 to fix ntfs_submit_bh_for_read() caller.
2. Added Reviewed-by from Christoph.

Ritesh Harjani (4):
jbd2: Drop useless return value of submit_bh
fs/ntfs: Drop useless return value of submit_bh from ntfs_submit_bh_for_read fs/buffer: Drop useless return value of submit_bh
fs/buffer: Make submit_bh & submit_bh_wbc return type as void

 fs/buffer.c                 | 19 ++++++++-----------
 fs/jbd2/commit.c            | 11 +++++------
 fs/jbd2/journal.c           |  6 ++----
 fs/ntfs/file.c              |  4 ++--
 include/linux/buffer_head.h |  2 +-
 5 files changed, 18 insertions(+), 24 deletions(-)

--
2.35.3

author
#1 lore raw

PATCH v2 1/4 jbd2: Drop useless return value of submit_bh

submit_bh always returns 0. This patch cleans up 2 of it's caller in jbd2 to drop submit_bh's useless return value.
Once all submit_bh callers are cleaned up, we can make it's return type as void.

Reviewed-by Christoph Hellwig <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>
---
 fs/jbd2/commit.c  | 11 +++++------
 fs/jbd2/journal.c |  6 ++----
 2 files changed, 7 insertions(+), 10 deletions(-)
fs/jbd2/commit.c +5 -6
index eb315e81f1a6..688fd960d01f 100644
@@ -122,8 +122,8 @@ static int journal_submit_commit_record(journal_t *journal,
 {
 	struct commit_header *tmp;
 	struct buffer_head *bh;
-	int ret;
 	struct timespec64 now;
+	int write_flags = REQ_SYNC;
 
 	*cbh = NULL;
 

@@ -155,13 +155,12 @@ static int journal_submit_commit_record(journal_t *journal,
 
 	if (journal->j_flags & JBD2_BARRIER &&
 	    !jbd2_has_feature_async_commit(journal))
-		ret = submit_bh(REQ_OP_WRITE,
-			REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
-	else
-		ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
+		write_flags |= REQ_PREFLUSH | REQ_FUA;
+
+	submit_bh(REQ_OP_WRITE, write_flags, bh);
 
 	*cbh = bh;
-	return ret;
+	return 0;
 }
 
 /*
fs/jbd2/journal.c +2 -4
index c0cbeeaec2d1..81a282e676bc 100644
@@ -1606,7 +1606,7 @@ static int jbd2_write_superblock(journal_t *journal, int write_flags)
 {
 	struct buffer_head *bh = journal->j_sb_buffer;
 	journal_superblock_t *sb = journal->j_superblock;
-	int ret;
+	int ret = 0;
 
 	/* Buffer got discarded which means block device got invalidated */
 	if (!buffer_mapped(bh)) {

@@ -1636,14 +1636,12 @@ static int jbd2_write_superblock(journal_t *journal, int write_flags)
 		sb->s_checksum = jbd2_superblock_csum(journal, sb);
 	get_bh(bh);
 	bh->b_end_io = end_buffer_write_sync;
-	ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
+	submit_bh(REQ_OP_WRITE, write_flags, bh);
 	wait_on_buffer(bh);
 	if (buffer_write_io_error(bh)) {
 		clear_buffer_write_io_error(bh);
 		set_buffer_uptodate(bh);
 		ret = -EIO;
-	}
-	if (ret) {
 		printk(KERN_ERR "JBD2: Error %d detected when updating "
 		       "journal superblock for %s.\n", ret,
 		       journal->j_devname);

--
2.35.3

author
#2 lore raw

PATCH v2 2/4 fs/ntfs: Drop useless return value of submit_bh from ntfs_submit_bh_for_read

In reply to Ritesh Harjani

submit_bh always returns 0. This patch drops the useless return value of submit_bh from ntfs_submit_bh_for_read(). Once all of submit_bh callers are cleaned up, we can make it's return type as void.

Reported-by kernel test robot <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>
---
 fs/ntfs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
fs/ntfs/file.c +2 -2
index a8abe2296514..2389bfa654a2 100644
@@ -532,12 +532,12 @@ static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
 	goto out;
 }
 
-static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
+static inline void ntfs_submit_bh_for_read(struct buffer_head *bh)
 {
 	lock_buffer(bh);
 	get_bh(bh);
 	bh->b_end_io = end_buffer_read_sync;
-	return submit_bh(REQ_OP_READ, 0, bh);
+	submit_bh(REQ_OP_READ, 0, bh);
 }
 
 /**

--
2.35.3

author
#3 lore raw

Re: [PATCHv2 2/4] fs/ntfs: Drop useless return value of submit_bh from ntfs_submit_bh_for_read

+ [email protected]
(sorry about not cc'ing this in the first place)

Quoted 32 lines · Ritesh Harjani

submit_bh always returns 0. This patch drops the useless return value of submit_bh from ntfs_submit_bh_for_read(). Once all of submit_bh callers are cleaned up, we can make it's return type as void.

Reported-by kernel test robot <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>
---
 fs/ntfs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
fs/ntfs/file.c +2 -3
index a8abe2296514..2389bfa654a2 100644
@@ -532,12 +532,12 @@ static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
 	goto out;
 }
 
-static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
+static inline void ntfs_submit_bh_for_read(struct buffer_head *bh)
 {
 	lock_buffer(bh);
 	get_bh(bh);
 	bh->b_end_io = end_buffer_read_sync;
-	return submit_bh(REQ_OP_READ, 0, bh);
+	submit_bh(REQ_OP_READ, 0, bh);
 }
 
 /**
--

2.35.3

reviewer Reviewed-by on v2 2/4
#4 lore raw

Re: [PATCHv2 2/4] fs/ntfs: Drop useless return value of submit_bh from ntfs_submit_bh_for_read

In reply to Ritesh Harjani
Quoted 6 lines · Ritesh Harjani

submit_bh always returns 0. This patch drops the useless return value of submit_bh from ntfs_submit_bh_for_read(). Once all of submit_bh callers are cleaned up, we can make it's return type as void.

Reported-by kernel test robot <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>

Looks good. Feel free to add:

Reviewed-by Jan Kara <[email protected]>

Honza

Quoted 26 lines
---
 fs/ntfs/file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
fs/ntfs/file.c +2 -3
index a8abe2296514..2389bfa654a2 100644
@@ -532,12 +532,12 @@ static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
 	goto out;
 }
 
-static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
+static inline void ntfs_submit_bh_for_read(struct buffer_head *bh)
 {
 	lock_buffer(bh);
 	get_bh(bh);
 	bh->b_end_io = end_buffer_read_sync;
-	return submit_bh(REQ_OP_READ, 0, bh);
+	submit_bh(REQ_OP_READ, 0, bh);
 }
 
 /**
--

2.35.3

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
Reviewed-by on v2 2/4
#5 lore raw

Re: [PATCHv2 2/4] fs/ntfs: Drop useless return value of submit_bh from ntfs_submit_bh_for_read

In reply to Ritesh Harjani
Quoted 3 lines · Ritesh Harjani

submit_bh always returns 0. This patch drops the useless return value of submit_bh from ntfs_submit_bh_for_read(). Once all of submit_bh callers are cleaned up, we can make it's return type as void.

Looks good:

Reviewed-by Christoph Hellwig <[email protected]>

and so sad that a newly merged file systems still does all this buffer head crap :(

author
#6 lore raw

PATCH v2 3/4 fs/buffer: Drop useless return value of submit_bh

In reply to Ritesh Harjani

submit_bh always returns 0. This patch drops the useless return value of submit_bh from __sync_dirty_buffer(). Once all of submit_bh callers are cleaned up, we can make it's return type as void.

Reviewed-by Christoph Hellwig <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>
---
 fs/buffer.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)
fs/buffer.c +4 -6
index 898c7f301b1b..313283af15b6 100644
@@ -3121,8 +3121,6 @@ EXPORT_SYMBOL(write_dirty_buffer);
  */
 int __sync_dirty_buffer(struct buffer_head *bh, int op_flags)
 {
-	int ret = 0;
-
 	WARN_ON(atomic_read(&bh->b_count) < 1);
 	lock_buffer(bh);
 	if (test_clear_buffer_dirty(bh)) {

@@ -3137,14 +3135,14 @@ int __sync_dirty_buffer(struct buffer_head *bh, int op_flags)
 
 		get_bh(bh);
 		bh->b_end_io = end_buffer_write_sync;
-		ret = submit_bh(REQ_OP_WRITE, op_flags, bh);
+		submit_bh(REQ_OP_WRITE, op_flags, bh);
 		wait_on_buffer(bh);
-		if (!ret && !buffer_uptodate(bh))
-			ret = -EIO;
+		if (!buffer_uptodate(bh))
+			return -EIO;
 	} else {
 		unlock_buffer(bh);
 	}
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(__sync_dirty_buffer);

--
2.35.3

author
#7 lore raw

PATCH v2 4/4 fs/buffer: Make submit_bh & submit_bh_wbc return type as void

In reply to Ritesh Harjani

submit_bh/submit_bh_wbc are non-blocking functions which just submit the bio and return. The caller of submit_bh/submit_bh_wbc needs to wait on buffer till I/O completion and then check buffer head's b_state field to know if there was any I/O error.

Hence there is no need for these functions to have any return type. Even now they always returns 0. Hence drop the return value and make their return type as void to avoid any confusion.

Reviewed-by Christoph Hellwig <[email protected]>
Signed-off-by Ritesh Harjani <[email protected]>
---
 fs/buffer.c                 | 9 ++++-----
 include/linux/buffer_head.h | 2 +-
 2 files changed, 5 insertions(+), 6 deletions(-)
fs/buffer.c +4 -5
index 313283af15b6..6671abc98e21 100644
@@ -52,7 +52,7 @@
 #include "internal.h"
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
-static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
+static void submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
 			 struct writeback_control *wbc);
 
 #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)

@@ -2994,7 +2994,7 @@ static void end_bio_bh_io_sync(struct bio *bio)
 	bio_put(bio);
 }
 
-static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
+static void submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
 			 struct writeback_control *wbc)
 {
 	struct bio *bio;

@@ -3037,12 +3037,11 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
 	}
 
 	submit_bio(bio);
-	return 0;
 }
 
-int submit_bh(int op, int op_flags, struct buffer_head *bh)
+void submit_bh(int op, int op_flags, struct buffer_head *bh)
 {
-	return submit_bh_wbc(op, op_flags, bh, NULL);
+	submit_bh_wbc(op, op_flags, bh, NULL);
 }
 EXPORT_SYMBOL(submit_bh);
include/linux/buffer_head.h +1 -1
index c9d1463bb20f..392d7d5aec05 100644
@@ -205,7 +205,7 @@ void ll_rw_block(int, int, int, struct buffer_head * bh[]);
 int sync_dirty_buffer(struct buffer_head *bh);
 int __sync_dirty_buffer(struct buffer_head *bh, int op_flags);
 void write_dirty_buffer(struct buffer_head *bh, int op_flags);
-int submit_bh(int, int, struct buffer_head *);
+void submit_bh(int op, int op_flags, struct buffer_head *bh);
 void write_boundary_block(struct block_device *bdev,
 			sector_t bblock, unsigned blocksize);
 int bh_uptodate_or_lock(struct buffer_head *bh);

--
2.35.3