* [PATCH linux-next] jffs2: reduce stack usage in jffs2_build_xattr_subsystem()
@ 2017-05-09 20:30 Fabian Frederick
2023-01-20 21:56 ` Nick Desaulniers
0 siblings, 1 reply; 2+ messages in thread
From: Fabian Frederick @ 2017-05-09 20:30 UTC (permalink / raw)
To: David Woodhouse; +Cc: linux-mtd, linux-kernel, fabf
Use kcalloc() for allocation/flush of 128 pointers table to
reduce stack usage.
Function now returns -ENOMEM or 0 on success.
stackusage
Before:
./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 1208
dynamic,bounded
After:
./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 192
dynamic,bounded
Also update definition when CONFIG_JFFS2_FS_XATTR is not enabled
Tested with an MTD mount point and some user set/getfattr.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
---
fs/jffs2/build.c | 5 ++++-
fs/jffs2/xattr.c | 14 ++++++++++----
fs/jffs2/xattr.h | 4 ++--
3 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
index b288c8a..f88e0bf 100644
--- a/fs/jffs2/build.c
+++ b/fs/jffs2/build.c
@@ -211,7 +211,10 @@ static int jffs2_build_filesystem(struct jffs2_sb_info *c)
ic->scan_dents = NULL;
cond_resched();
}
- jffs2_build_xattr_subsystem(c);
+ ret = jffs2_build_xattr_subsystem(c);
+ if (ret)
+ goto exit;
+
c->flags &= ~JFFS2_SB_FLAG_BUILDING;
dbg_fsbuild("FS build complete\n");
diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
index da3e185..95c0496 100644
--- a/fs/jffs2/xattr.c
+++ b/fs/jffs2/xattr.c
@@ -772,10 +772,10 @@ void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c)
}
#define XREF_TMPHASH_SIZE (128)
-void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
+int jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
{
struct jffs2_xattr_ref *ref, *_ref;
- struct jffs2_xattr_ref *xref_tmphash[XREF_TMPHASH_SIZE];
+ struct jffs2_xattr_ref **xref_tmphash;
struct jffs2_xattr_datum *xd, *_xd;
struct jffs2_inode_cache *ic;
struct jffs2_raw_node_ref *raw;
@@ -784,9 +784,13 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
BUG_ON(!(c->flags & JFFS2_SB_FLAG_BUILDING));
+
+ xref_tmphash = kcalloc(XREF_TMPHASH_SIZE,
+ sizeof(struct jffs2_xattr_ref *), GFP_KERNEL);
+ if (!xref_tmphash)
+ return -ENOMEM;
+
/* Phase.1 : Merge same xref */
- for (i=0; i < XREF_TMPHASH_SIZE; i++)
- xref_tmphash[i] = NULL;
for (ref=c->xref_temp; ref; ref=_ref) {
struct jffs2_xattr_ref *tmp;
@@ -884,6 +888,8 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
"%u of xref (%u dead, %u orphan) found.\n",
xdatum_count, xdatum_unchecked_count, xdatum_orphan_count,
xref_count, xref_dead_count, xref_orphan_count);
+ kfree(xref_tmphash);
+ return 0;
}
struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
diff --git a/fs/jffs2/xattr.h b/fs/jffs2/xattr.h
index 720007b..1b5030a 100644
--- a/fs/jffs2/xattr.h
+++ b/fs/jffs2/xattr.h
@@ -71,7 +71,7 @@ static inline int is_xattr_ref_dead(struct jffs2_xattr_ref *ref)
#ifdef CONFIG_JFFS2_FS_XATTR
extern void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c);
-extern void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c);
+extern int jffs2_build_xattr_subsystem(struct jffs2_sb_info *c);
extern void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c);
extern struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
@@ -103,7 +103,7 @@ extern ssize_t jffs2_listxattr(struct dentry *, char *, size_t);
#else
#define jffs2_init_xattr_subsystem(c)
-#define jffs2_build_xattr_subsystem(c)
+#define jffs2_build_xattr_subsystem(c) (0)
#define jffs2_clear_xattr_subsystem(c)
#define jffs2_xattr_do_crccheck_inode(c, ic)
--
2.9.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH linux-next] jffs2: reduce stack usage in jffs2_build_xattr_subsystem()
2017-05-09 20:30 [PATCH linux-next] jffs2: reduce stack usage in jffs2_build_xattr_subsystem() Fabian Frederick
@ 2023-01-20 21:56 ` Nick Desaulniers
0 siblings, 0 replies; 2+ messages in thread
From: Nick Desaulniers @ 2023-01-20 21:56 UTC (permalink / raw)
To: David Woodhouse
Cc: David Woodhouse, linux-mtd, linux-kernel, tim.gardner, lkp, re, nathan
On Tue, May 09, 2017 at 10:30:03PM +0200, Fabian Frederick wrote:
> Use kcalloc() for allocation/flush of 128 pointers table to
> reduce stack usage.
>
> Function now returns -ENOMEM or 0 on success.
>
> stackusage
> Before:
> ./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 1208
> dynamic,bounded
>
> After:
> ./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 192
> dynamic,bounded
>
> Also update definition when CONFIG_JFFS2_FS_XATTR is not enabled
>
> Tested with an MTD mount point and some user set/getfattr.
>
> Signed-off-by: Fabian Frederick <fabf@skynet.be>
Hi David,
Any chance this patch can get picked up? It LGTM, and I see multiple
reports of this issue on lore:
https://lore.kernel.org/lkml/?q=jffs2_build_xattr_subsystem
Reported-by: Tim Gardner <tim.gardner@canonical.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Ron Economos <re@w6rz.net>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> fs/jffs2/build.c | 5 ++++-
> fs/jffs2/xattr.c | 14 ++++++++++----
> fs/jffs2/xattr.h | 4 ++--
> 3 files changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
> index b288c8a..f88e0bf 100644
> --- a/fs/jffs2/build.c
> +++ b/fs/jffs2/build.c
> @@ -211,7 +211,10 @@ static int jffs2_build_filesystem(struct jffs2_sb_info *c)
> ic->scan_dents = NULL;
> cond_resched();
> }
> - jffs2_build_xattr_subsystem(c);
> + ret = jffs2_build_xattr_subsystem(c);
> + if (ret)
> + goto exit;
> +
> c->flags &= ~JFFS2_SB_FLAG_BUILDING;
>
> dbg_fsbuild("FS build complete\n");
> diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
> index da3e185..95c0496 100644
> --- a/fs/jffs2/xattr.c
> +++ b/fs/jffs2/xattr.c
> @@ -772,10 +772,10 @@ void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c)
> }
>
> #define XREF_TMPHASH_SIZE (128)
> -void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
> +int jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
> {
> struct jffs2_xattr_ref *ref, *_ref;
> - struct jffs2_xattr_ref *xref_tmphash[XREF_TMPHASH_SIZE];
> + struct jffs2_xattr_ref **xref_tmphash;
> struct jffs2_xattr_datum *xd, *_xd;
> struct jffs2_inode_cache *ic;
> struct jffs2_raw_node_ref *raw;
> @@ -784,9 +784,13 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
>
> BUG_ON(!(c->flags & JFFS2_SB_FLAG_BUILDING));
>
> +
> + xref_tmphash = kcalloc(XREF_TMPHASH_SIZE,
> + sizeof(struct jffs2_xattr_ref *), GFP_KERNEL);
> + if (!xref_tmphash)
> + return -ENOMEM;
> +
> /* Phase.1 : Merge same xref */
> - for (i=0; i < XREF_TMPHASH_SIZE; i++)
> - xref_tmphash[i] = NULL;
> for (ref=c->xref_temp; ref; ref=_ref) {
> struct jffs2_xattr_ref *tmp;
>
> @@ -884,6 +888,8 @@ void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
> "%u of xref (%u dead, %u orphan) found.\n",
> xdatum_count, xdatum_unchecked_count, xdatum_orphan_count,
> xref_count, xref_dead_count, xref_orphan_count);
> + kfree(xref_tmphash);
> + return 0;
> }
>
> struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
> diff --git a/fs/jffs2/xattr.h b/fs/jffs2/xattr.h
> index 720007b..1b5030a 100644
> --- a/fs/jffs2/xattr.h
> +++ b/fs/jffs2/xattr.h
> @@ -71,7 +71,7 @@ static inline int is_xattr_ref_dead(struct jffs2_xattr_ref *ref)
> #ifdef CONFIG_JFFS2_FS_XATTR
>
> extern void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c);
> -extern void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c);
> +extern int jffs2_build_xattr_subsystem(struct jffs2_sb_info *c);
> extern void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c);
>
> extern struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
> @@ -103,7 +103,7 @@ extern ssize_t jffs2_listxattr(struct dentry *, char *, size_t);
> #else
>
> #define jffs2_init_xattr_subsystem(c)
> -#define jffs2_build_xattr_subsystem(c)
> +#define jffs2_build_xattr_subsystem(c) (0)
> #define jffs2_clear_xattr_subsystem(c)
>
> #define jffs2_xattr_do_crccheck_inode(c, ic)
> --
> 2.9.3
>
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