btrfs: allocate btrfs_ioctl_defrag_range_args on stack

Instead of using kmalloc() to allocate btrfs_ioctl_defrag_range_args,
allocate btrfs_ioctl_defrag_range_args on stack, the size is reasonably
small and ioctls are called in process context.

sizeof(btrfs_ioctl_defrag_range_args) = 48

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3d0ae797cd8d5ee00374c83ea1d2edb0d8c5c99f..d09eaa83b5d27f8e237b9d617580d4cc2bf21466 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3096,7 +3096,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 {
        struct inode *inode = file_inode(file);
        struct btrfs_root *root = BTRFS_I(inode)->root;
-       struct btrfs_ioctl_defrag_range_args *range;
+       struct btrfs_ioctl_defrag_range_args range = {0};
        int ret;
 
        ret = mnt_want_write_file(file);
@@ -3134,33 +3134,24 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                        goto out;
                }
 
-               range = kzalloc(sizeof(*range), GFP_KERNEL);
-               if (!range) {
-                       ret = -ENOMEM;
-                       goto out;
-               }
-
                if (argp) {
-                       if (copy_from_user(range, argp,
-                                          sizeof(*range))) {
+                       if (copy_from_user(&range, argp, sizeof(range))) {
                                ret = -EFAULT;
-                               kfree(range);
                                goto out;
                        }
                        /* compression requires us to start the IO */
-                       if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
-                               range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
-                               range->extent_thresh = (u32)-1;
+                       if ((range.flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
+                               range.flags |= BTRFS_DEFRAG_RANGE_START_IO;
+                               range.extent_thresh = (u32)-1;
                        }
                } else {
                        /* the rest are all set to zero by kzalloc */
-                       range->len = (u64)-1;
+                       range.len = (u64)-1;
                }
                ret = btrfs_defrag_file(file_inode(file), file,
-                                       range, BTRFS_OLDEST_GENERATION, 0);
+                                       &range, BTRFS_OLDEST_GENERATION, 0);
                if (ret > 0)
                        ret = 0;
-               kfree(range);
                break;
        default:
                ret = -EINVAL;