xfs: return if_data from xfs_idata_realloc

Many of the xfs_idata_realloc callers need to set a local pointer to the
just reallocated if_data memory.  Return the pointer to simplify them a
bit and use the opportunity to re-use krealloc for freeing if_data if the
size hits 0.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -690,8 +690,8 @@ xfs_attr_shortform_create(
 	ASSERT(ifp->if_bytes == 0);
 	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS)
 		ifp->if_format = XFS_DINODE_FMT_LOCAL;
-	xfs_idata_realloc(dp, sizeof(*hdr), XFS_ATTR_FORK);
-	hdr = ifp->if_data;
+
+	hdr = xfs_idata_realloc(dp, sizeof(*hdr), XFS_ATTR_FORK);
 	memset(hdr, 0, sizeof(*hdr));
 	hdr->totsize = cpu_to_be16(sizeof(*hdr));
 	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);
@@ -767,8 +767,7 @@ xfs_attr_shortform_add(
 
 	offset = (char *)sfe - (char *)sf;
 	size = xfs_attr_sf_entsize_byname(args->namelen, args->valuelen);
-	xfs_idata_realloc(dp, size, XFS_ATTR_FORK);
-	sf = ifp->if_data;
+	sf = xfs_idata_realloc(dp, size, XFS_ATTR_FORK);
 	sfe = (struct xfs_attr_sf_entry *)((char *)sf + offset);
 
 	sfe->namelen = args->namelen;

fs/xfs/libxfs/xfs_dir2_sf.c

@@ -466,12 +466,11 @@ xfs_dir2_sf_addname_easy(
 	/*
 	 * Grow the in-inode space.
 	 */
-	xfs_idata_realloc(dp, xfs_dir2_sf_entsize(mp, sfp, args->namelen),
+	sfp = xfs_idata_realloc(dp, xfs_dir2_sf_entsize(mp, sfp, args->namelen),
 			  XFS_DATA_FORK);
 	/*
 	 * Need to set up again due to realloc of the inode data.
 	 */
-	sfp = dp->i_df.if_data;
 	sfep = (xfs_dir2_sf_entry_t *)((char *)sfp + byteoff);
 	/*
 	 * Fill in the new entry.
@@ -551,11 +550,8 @@ xfs_dir2_sf_addname_hard(
 	 * the data.
 	 */
 	xfs_idata_realloc(dp, -old_isize, XFS_DATA_FORK);
-	xfs_idata_realloc(dp, new_isize, XFS_DATA_FORK);
-	/*
-	 * Reset the pointer since the buffer was reallocated.
-	 */
-	sfp = dp->i_df.if_data;
+	sfp = xfs_idata_realloc(dp, new_isize, XFS_DATA_FORK);
+
 	/*
 	 * Copy the first part of the directory, including the header.
 	 */
@@ -820,15 +816,13 @@ xfs_dir2_sf_create(
 	ASSERT(dp->i_df.if_bytes == 0);
 	i8count = pino > XFS_DIR2_MAX_SHORT_INUM;
 	size = xfs_dir2_sf_hdr_size(i8count);
+
 	/*
-	 * Make a buffer for the data.
-	 */
-	xfs_idata_realloc(dp, size, XFS_DATA_FORK);
-	/*
-	 * Fill in the header,
+	 * Make a buffer for the data and fill in the header.
 	 */
-	sfp = dp->i_df.if_data;
+	sfp = xfs_idata_realloc(dp, size, XFS_DATA_FORK);
 	sfp->i8count = i8count;
+
 	/*
 	 * Now can put in the inode number, since i8count is set.
 	 */
@@ -976,11 +970,12 @@ xfs_dir2_sf_removename(
 	 */
 	sfp->count--;
 	dp->i_disk_size = newsize;
+
 	/*
 	 * Reallocate, making it smaller.
 	 */
-	xfs_idata_realloc(dp, newsize - oldsize, XFS_DATA_FORK);
-	sfp = dp->i_df.if_data;
+	sfp = xfs_idata_realloc(dp, newsize - oldsize, XFS_DATA_FORK);
+
 	/*
 	 * Are we changing inode number size?
 	 */

fs/xfs/libxfs/xfs_inode_fork.c

@@ -496,7 +496,7 @@ xfs_iroot_realloc(
  * byte_diff -- the change in the number of bytes, positive or negative,
  *	 requested for the if_data array.
  */
-void
+void *
 xfs_idata_realloc(
 	struct xfs_inode	*ip,
 	int64_t			byte_diff,
@@ -508,19 +508,15 @@ xfs_idata_realloc(
 	ASSERT(new_size >= 0);
 	ASSERT(new_size <= xfs_inode_fork_size(ip, whichfork));
 
-	if (byte_diff == 0)
-		return;
-
-	if (new_size == 0) {
-		kmem_free(ifp->if_data);
-		ifp->if_data = NULL;
-		ifp->if_bytes = 0;
-		return;
+	if (byte_diff) {
+		ifp->if_data = krealloc(ifp->if_data, new_size,
+					GFP_NOFS | __GFP_NOFAIL);
+		if (new_size == 0)
+			ifp->if_data = NULL;
+		ifp->if_bytes = new_size;
 	}
 
-	ifp->if_data = krealloc(ifp->if_data, new_size,
-			GFP_NOFS | __GFP_NOFAIL);
-	ifp->if_bytes = new_size;
+	return ifp->if_data;
 }
 
 /* Free all memory and reset a fork back to its initial state. */

fs/xfs/libxfs/xfs_inode_fork.h

@@ -168,7 +168,7 @@ int		xfs_iformat_attr_fork(struct xfs_inode *, struct xfs_dinode *);
 void		xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
 				struct xfs_inode_log_item *, int);
 void		xfs_idestroy_fork(struct xfs_ifork *ifp);
-void		xfs_idata_realloc(struct xfs_inode *ip, int64_t byte_diff,
+void *		xfs_idata_realloc(struct xfs_inode *ip, int64_t byte_diff,
 				int whichfork);
 void		xfs_iroot_realloc(struct xfs_inode *, int, int);
 int		xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);