[PATCH v2 0/8] Introduce strreplace

[PATCH v2 0/8] Introduce strreplace

[Rasmus Villemoes]

Doing single-character substitution on an entire string is open-coded
in a few places, sometimes in a rather suboptimal way. This introduces
a trivial helper, strreplace, for this task along with a few example
conversions.

Andrew, can I get you to take 1/8 through the mm tree? I'm not sure
what the easiest path is for the remaining patches.

Rasmus Villemoes (8):
  lib: string: Introduce strreplace
  kernel/trace/trace_events_filter.c: Use strreplace
  blktrace: use strreplace in do_blk_trace_setup
  lib/kobject.c: Use strreplace
  drivers/base/core.c: Use strreplace
  drivers/md/md.c: Use strreplace
  fs/jbd2/journal.c: Use strreplace
  fs/ext4/super.c: Use strreplace in ext4_fill_super

 drivers/base/core.c                |  9 ++++-----
 drivers/md/md.c                    |  4 +---
 fs/ext4/super.c                    |  4 +---
 fs/jbd2/journal.c                  | 10 ++--------
 include/linux/string.h             |  1 +
 kernel/trace/blktrace.c            |  6 ++----
 kernel/trace/trace_events_filter.c |  5 ++---
 lib/kobject.c                      | 13 +++++--------
 lib/string.c                       | 17 +++++++++++++++++
 9 files changed, 35 insertions(+), 34 deletions(-)

-- 
2.1.3

[PATCH v2 7/8] fs/jbd2/journal.c: Use strreplace

[Rasmus Villemoes]

In one case, we eliminate a local variable; in the other a strlen()
call and some .text.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
v2: no changes.

 fs/jbd2/journal.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index b96bd8076b70..5c187ded12d6 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1137,7 +1137,6 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev,
 {
 	journal_t *journal = journal_init_common();
 	struct buffer_head *bh;
-	char *p;
 	int n;
 
 	if (!journal)
@@ -1150,9 +1149,7 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev,
 	journal->j_blk_offset = start;
 	journal->j_maxlen = len;
 	bdevname(journal->j_dev, journal->j_devname);
-	p = journal->j_devname;
-	while ((p = strchr(p, '/')))
-		*p = '!';
+	strreplace(journal->j_devname, '/', '!');
 	jbd2_stats_proc_init(journal);
 	n = journal->j_blocksize / sizeof(journal_block_tag_t);
 	journal->j_wbufsize = n;
@@ -1204,10 +1201,7 @@ journal_t * jbd2_journal_init_inode (struct inode *inode)
 	journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
 	journal->j_inode = inode;
 	bdevname(journal->j_dev, journal->j_devname);
-	p = journal->j_devname;
-	while ((p = strchr(p, '/')))
-		*p = '!';
-	p = journal->j_devname + strlen(journal->j_devname);
+	p = strreplace(journal->j_devname, '/', '!');
 	sprintf(p, "-%lu", journal->j_inode->i_ino);
 	jbd_debug(1,
 		  "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
-- 
2.1.3

[PATCH v2 8/8] fs/ext4/super.c: Use strreplace in ext4_fill_super

[Rasmus Villemoes]

This makes a very large function a little smaller.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
v2: no changes.

 fs/ext4/super.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ca9d4a2fed41..5f3c43a66937 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3420,7 +3420,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	unsigned long journal_devnum = 0;
 	unsigned long def_mount_opts;
 	struct inode *root;
-	char *cp;
 	const char *descr;
 	int ret = -ENOMEM;
 	int blocksize, clustersize;
@@ -3456,8 +3455,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 #endif
 
 	/* Cleanup superblock name */
-	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
-		*cp = '!';
+	strreplace(sb->s_id, '/', '!');
 
 	/* -EINVAL is default */
 	ret = -EINVAL;
-- 
2.1.3

Re: [PATCH v2 0/8] Introduce strreplace

[Theodore Ts'o]

On Tue, Jun 09, 2015 at 01:26:48AM +0200, Rasmus Villemoes wrote:
> Doing single-character substitution on an entire string is open-coded
> in a few places, sometimes in a rather suboptimal way. This introduces
> a trivial helper, strreplace, for this task along with a few example
> conversions.
> 
> Andrew, can I get you to take 1/8 through the mm tree? I'm not sure
> what the easiest path is for the remaining patches.

This is not super urgent, right?  So we could let 1/8 go into
mainline, and then the rest of the patches could go in the next
release.  That would be the simplest, although it would drag out how
long it would take for strreplace to be used everywhere.

     	      	       		     	     - Ted

Re: [PATCH v2 0/8] Introduce strreplace

[Rasmus Villemoes]

On Tue, Jun 09 2015, Theodore Ts'o <tytso@mit.edu> wrote:

> On Tue, Jun 09, 2015 at 01:26:48AM +0200, Rasmus Villemoes wrote:
>> Doing single-character substitution on an entire string is open-coded
>> in a few places, sometimes in a rather suboptimal way. This introduces
>> a trivial helper, strreplace, for this task along with a few example
>> conversions.
>> 
>> Andrew, can I get you to take 1/8 through the mm tree? I'm not sure
>> what the easiest path is for the remaining patches.
>
> This is not super urgent, right?

Right, not urgent at all.

> So we could let 1/8 go into mainline, and then the rest of the patches
> could go in the next release. That would be the simplest, although it
> would drag out how long it would take for strreplace to be used
> everywhere.

Sure, though it would be a little weird to have a helper with no users
until 4.3 comes out.

Rasmus

Re: [PATCH v2 0/8] Introduce strreplace

[Andrew Morton]

On Tue,  9 Jun 2015 01:26:48 +0200 Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:

> Doing single-character substitution on an entire string is open-coded
> in a few places, sometimes in a rather suboptimal way. This introduces
> a trivial helper, strreplace, for this task along with a few example
> conversions.
> 
> Andrew, can I get you to take 1/8 through the mm tree? I'm not sure
> what the easiest path is for the remaining patches.

With this sort of thing I grab everything them feed the dependent
patches to maintainers after the base patch is upstream.

Or I merge the dependent patches myself if they were acked.

Or if the dependent patches are simple I'll just merge them anyway,
shrug.  I'd say these fall into that category.