[PATCH 1/2] nfsd: fix type mismatch and explain host-endian xdr buffer usage

sparse flagged this type mismatch. Also the xdr buffer usage is a bit
non-standard, so explain what we're doing and why.

Fixes: 4b64b811f368 ("nfsd: add notification handlers for dir events")
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Jeff Layton <[email protected]>
---
 fs/nfsd/nfs4xdr.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index a47eb544b99f..5cbb4a415384 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4383,13 +4383,18 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 	struct path path = nf->nf_file->f_path;
 	struct nfsd4_fattr_args args = { };
 	const u32 *reqmask;
-	uint32_t *attrmask;
+	u32 *attrmask;
 	__be32 status;
 	bool parent;
 	int ret;
 
-	/* Reserve space for attrmask */
-	attrmask = xdr_reserve_space(xdr, 3 * sizeof(uint32_t));
+	/*
+	 * attrmask is the host-order bmval[3] that nfsd4_encode_attr_vals()
+	 * consumes and that ne_attrs.attrmask.element points at. It must
+	 * outlive this call, so steal a few words from the xdr stream to hold
+	 * it.
+	 */
+	attrmask = (u32 *)xdr_reserve_space(xdr, 3 * sizeof(*attrmask));
 	if (!attrmask)
 		return false;
 

-- 
2.55.0