[PATCH 3/3] NFS: Modernize decode_getdevinfo() bitmap decoding

[Anna Schumaker <anna@kernel.org>]

From: Anna Schumaker <anna.schumaker@hammerspace.com>

Use the decode_bitmap4() function for decoding notification bitmaps.
This function calls xdr_stream_decode_uint32_array() to do proper bounds
and overflow checking.

Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
---
 fs/nfs/nfs4xdr.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 4d12b97f423e..c0971af20154 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -6064,7 +6064,7 @@ static int decode_getdeviceinfo(struct xdr_stream *xdr,
 {
 	struct pnfs_device *pdev = res->pdev;
 	__be32 *p;
-	uint32_t len, type;
+	uint32_t type;
 	int status;
 
 	status = decode_op_hdr(xdr, OP_GETDEVICEINFO);
@@ -6099,26 +6099,8 @@ static int decode_getdeviceinfo(struct xdr_stream *xdr,
 		return -EIO;
 
 	/* Parse notification bitmap, verifying that it is zero. */
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(!p))
+	if (decode_bitmap4(xdr, &res->notification, 1) < 0)
 		return -EIO;
-	len = be32_to_cpup(p);
-	if (len) {
-		uint32_t i;
-
-		p = xdr_inline_decode(xdr, 4 * len);
-		if (unlikely(!p))
-			return -EIO;
-
-		res->notification = be32_to_cpup(p++);
-		for (i = 1; i < len; i++) {
-			if (be32_to_cpup(p++)) {
-				dprintk("%s: unsupported notification\n",
-					__func__);
-				return -EIO;
-			}
-		}
-	}
 	return 0;
 }
 
-- 
2.56.0