xfs/libxfs: replace kmalloc() and memcpy() with kmemdup()

Source kernel commit: 9d9b72472631262b35157f1a650f066c0e11c2bb

The source static analysis tool gave the following advice:

./fs/xfs/libxfs/xfs_dir2.c:382:15-22: WARNING opportunity for kmemdup

→ 382         args->value = kmalloc(len,
383                          GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_RETRY_MAYFAIL);
384         if (!args->value)
385                 return -ENOMEM;
386
→ 387         memcpy(args->value, name, len);
388         args->valuelen = len;
389         return -EEXIST;

Replacing kmalloc() + memcpy() with kmemdump() doesn't change semantics.
Original code works without fault, so this is not a bug fix but proposed improvement.

Link: https://lwn.net/Articles/198928/
Fixes: 94a69db2367ef ("xfs: use __GFP_NOLOCKDEP instead of GFP_NOFS")
Fixes: 384f3ced07efd ("[XFS] Return case-insensitive match for dentry cache")
Fixes: 2451337dd0439 ("xfs: global error sign conversion")
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Chandan Babu R <chandanbabu@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: linux-xfs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

diff --git a/include/kmem.h b/include/kmem.h
index 16a7957f1acee3708eebe747673601b643183365..66f8b1fbea8fdfecb3279b8520cdce22ed2b992a 100644 (file)
--- a/include/kmem.h
+++ b/include/kmem.h
@@ -79,4 +79,13 @@ static inline void kfree_rcu_mightsleep(const void *ptr)
 __attribute__((format(printf,2,3)))
 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 
+static inline void *kmemdup(const void *src, size_t len, gfp_t gfp)
+{
+       void *p = kmalloc(len, gfp);
+
+       if (p)
+               memcpy(p, src, len);
+       return p;
+}
+
 #endif

diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 29e64603d4ae82bbcf5c72de888b22edbcb833fc..1285019b674423ace568718f2c35640fb5287d43 100644 (file)
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -378,12 +378,11 @@ xfs_dir_cilookup_result(
                                        !(args->op_flags & XFS_DA_OP_CILOOKUP))
                return -EEXIST;
 
-       args->value = kmalloc(len,
+       args->value = kmemdup(name, len,
                        GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_RETRY_MAYFAIL);
        if (!args->value)
                return -ENOMEM;
 
-       memcpy(args->value, name, len);
        args->valuelen = len;
        return -EEXIST;
 }