From eee53f6eb7561f516b9c4bac829ce31c48096130 Mon Sep 17 00:00:00 2001 From: Fabian Frederick Date: Tue, 9 May 2017 22:30:03 +0200 Subject: [PATCH] jffs2: reduce stack usage in jffs2_build_xattr_subsystem() 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. Many current target on OpenWRT also suffer from a compilation warning (that become an error with CONFIG_WERROR) with the following output: fs/jffs2/xattr.c: In function 'jffs2_build_xattr_subsystem': fs/jffs2/xattr.c:887:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] 887 | } | ^ Using dynamic allocation fix this compilation warning. Fixes: c9f700f840bd ("[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion") Reported-by: Tim Gardner Reported-by: kernel test robot Reported-by: Ron Economos Reported-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Fabian Frederick Signed-off-by: Christian Marangi Cc: stable@vger.kernel.org --- fs/jffs2/build.c | 5 ++++- fs/jffs2/xattr.c | 13 +++++++++---- fs/jffs2/xattr.h | 4 ++-- 3 files changed, 15 insertions(+), 7 deletions(-) --- a/fs/jffs2/build.c +++ b/fs/jffs2/build.c @@ -211,7 +211,10 @@ static int jffs2_build_filesystem(struct 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"); --- a/fs/jffs2/xattr.c +++ b/fs/jffs2/xattr.c @@ -772,10 +772,10 @@ void jffs2_clear_xattr_subsystem(struct } #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 +784,12 @@ void jffs2_build_xattr_subsystem(struct 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 +887,8 @@ void jffs2_build_xattr_subsystem(struct "%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, --- a/fs/jffs2/xattr.h +++ b/fs/jffs2/xattr.h @@ -71,7 +71,7 @@ static inline int is_xattr_ref_dead(stru #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 de #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)