xfs: convert buf_cancel_table allocation to kmalloc_array

While we're messing around with how recovery allocates and frees the
buffer cancellation table, convert the allocation to use kmalloc_array
instead of the old kmem_alloc APIs, and make it handle a null return,
even though that's not likely.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_log_recover.h

@@ -122,7 +122,7 @@ int xlog_recover_iget(struct xfs_mount *mp, xfs_ino_t ino,
 		struct xfs_inode **ipp);
 void xlog_recover_release_intent(struct xlog *log, unsigned short intent_type,
 		uint64_t intent_id);
-void xlog_alloc_buf_cancel_table(struct xlog *log);
+int xlog_alloc_buf_cancel_table(struct xlog *log);
 void xlog_free_buf_cancel_table(struct xlog *log);
 
 #ifdef DEBUG

fs/xfs/xfs_buf_item_recover.c

@@ -1015,19 +1015,25 @@ xlog_check_buf_cancel_table(
 }
 #endif
 
-void
+int
 xlog_alloc_buf_cancel_table(
 	struct xlog	*log)
 {
+	void		*p;
 	int		i;
 
 	ASSERT(log->l_buf_cancel_table == NULL);
 
-	log->l_buf_cancel_table = kmem_zalloc(XLOG_BC_TABLE_SIZE *
-						 sizeof(struct list_head),
-						 0);
+	p = kmalloc_array(XLOG_BC_TABLE_SIZE, sizeof(struct list_head),
+			  GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	log->l_buf_cancel_table = p;
 	for (i = 0; i < XLOG_BC_TABLE_SIZE; i++)
 		INIT_LIST_HEAD(&log->l_buf_cancel_table[i]);
+
+	return 0;
 }
 
 void

fs/xfs/xfs_log_recover.c

@@ -3231,7 +3231,9 @@ xlog_do_log_recovery(
 	 * First do a pass to find all of the cancelled buf log items.
 	 * Store them in the buf_cancel_table for use in the second pass.
 	 */
-	xlog_alloc_buf_cancel_table(log);
+	error = xlog_alloc_buf_cancel_table(log);
+	if (error)
+		return error;
 
 	error = xlog_do_recovery_pass(log, head_blk, tail_blk,
 				      XLOG_RECOVER_PASS1, NULL);