[XFS] stop using uio in the readlink code

Simplify the readlink code to get rid of the last user of uio.

SGI-PV: 968563
SGI-Modid: xfs-linux-melb:xfs-kern:29479a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 45 insertions, 18 deletions

diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 5917808abbd6..47cfde6cfae2 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -349,19 +349,44 @@ xfs_open_by_handle(
         return new_fd;
 }
 
+/*
+ * This is a copy from fs/namei.c:vfs_readlink(), except for removing it's
+ * unused first argument.
+ */
+STATIC int
+do_readlink(
+        char __user             *buffer,
+        int                     buflen,
+        const char              *link)
+{
+        int len;
+
+        len = PTR_ERR(link);
+        if (IS_ERR(link))
+                goto out;
+
+        len = strlen(link);
+        if (len > (unsigned) buflen)
+                len = buflen;
+        if (copy_to_user(buffer, link, len))
+                len = -EFAULT;
+ out:
+        return len;
+}
+
+
 STATIC int
 xfs_readlink_by_handle(
         xfs_mount_t             *mp,
         void                    __user *arg,
         struct inode            *parinode)
 {
-        int                     error;
-        struct iovec            aiov;
-        struct uio              auio;
         struct inode            *inode;
         xfs_fsop_handlereq_t    hreq;
         bhv_vnode_t             *vp;
         __u32                   olen;
+        void                    *link;
+        int                     error;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -XFS_ERROR(EPERM);
@@ -374,29 +399,31 @@ xfs_readlink_by_handle(
 
         /* Restrict this handle operation to symlinks only. */
         if (!S_ISLNK(inode->i_mode)) {
-                VN_RELE(vp);
-                return -XFS_ERROR(EINVAL);
+                error = -XFS_ERROR(EINVAL);
+                goto out_iput;
         }
 
         if (copy_from_user(&olen, hreq.ohandlen, sizeof(__u32))) {
-                VN_RELE(vp);
-                return -XFS_ERROR(EFAULT);
+                error = -XFS_ERROR(EFAULT);
+                goto out_iput;
         }
-        aiov.iov_len    = olen;
-        aiov.iov_base   = hreq.ohandle;
 
-        auio.uio_iov    = (struct kvec *)&aiov;
-        auio.uio_iovcnt = 1;
-        auio.uio_offset = 0;
-        auio.uio_segflg = UIO_USERSPACE;
-        auio.uio_resid  = olen;
+        link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
+        if (!link)
+                goto out_iput;
 
-        error = bhv_vop_readlink(vp, &auio, IO_INVIS, NULL);
-        VN_RELE(vp);
+        error = -bhv_vop_readlink(vp, link);
         if (error)
-                return -error;
+                goto out_kfree;
+        error = do_readlink(hreq.ohandle, olen, link);
+        if (error)
+                goto out_kfree;
 
-        return (olen - auio.uio_resid);
+ out_kfree:
+        kfree(link);
+ out_iput:
+        iput(inode);
+        return error;
 }
 
 STATIC int