nfs: move nfs_fhandle_hash to common include file

lockd needs to be able to hash filehandles for tracepoints. Move the
nfs_fhandle_hash() helper to a common nfs include file.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/nfs.h b/include/linux/nfs.h
index b06375e88e58..ceb70a926b95 100644
--- a/include/linux/nfs.h
+++ b/include/linux/nfs.h
@@ -10,6 +10,7 @@
 
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/string.h>
+#include <linux/crc32.h>
 #include <uapi/linux/nfs.h>
 
 /*
@@ -44,4 +45,23 @@ enum nfs3_stable_how {
 	/* used by direct.c to mark verf as invalid */
 	NFS_INVALID_STABLE_HOW = -1
 };
+
+#ifdef CONFIG_CRC32
+/**
+ * nfs_fhandle_hash - calculate the crc32 hash for the filehandle
+ * @fh - pointer to filehandle
+ *
+ * returns a crc32 hash for the filehandle that is compatible with
+ * the one displayed by "wireshark".
+ */
+static inline u32 nfs_fhandle_hash(const struct nfs_fh *fh)
+{
+	return ~crc32_le(0xFFFFFFFF, &fh->data[0], fh->size);
+}
+#else /* CONFIG_CRC32 */
+static inline u32 nfs_fhandle_hash(const struct nfs_fh *fh)
+{
+	return 0;
+}
+#endif /* CONFIG_CRC32 */
 #endif /* _LINUX_NFS_H */