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Commit e9a3310b authored by Fabian Frederick's avatar Fabian Frederick Committed by Greg Kroah-Hartman
Browse files

jffs2: reduce stack usage in jffs2_build_xattr_subsystem() 



commit 1168f095417643f663caa341211e117db552989f upstream.

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: c9f700f8 ("[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion")
Reported-by: default avatarTim Gardner <tim.gardner@canonical.com>
Reported-by: default avatarkernel test robot <lkp@intel.com>
Reported-by: default avatarRon Economos <re@w6rz.net>
Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
Signed-off-by: default avatarChristian Marangi <ansuelsmth@gmail.com>
Cc: stable@vger.kernel.org
Message-Id: <20230506045612.16616-1-ansuelsmth@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a249a61a

fs/jffs2/build.c

+4 −1
Original line number Diff line number Diff line
@@ -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");

fs/jffs2/xattr.c

+9 −4
Original line number Diff line number Diff line
@@ -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 +784,12 @@ 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 +887,8 @@ 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,

fs/jffs2/xattr.h

+2 −2
Original line number Diff line number Diff line
@@ -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)