[SCSI] libfc: add fc_frame_sid() and fc_frame_did() functions

To pave the way for eliminating exchanges from incoming requests,
add simple inline fc_frame_sid() and fc_frame_did() functions
which get the FC_IDs from the frame header.  This can be almost
as efficient as getting them from the sequence/exchange.

Move ntohll, htonll, ntoh24 and hton24 to <scsi/fc_frame.h>
since we need them there and that's included by <scsi/libfc.h>

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 44 insertions, 1 deletions

diff --git a/include/scsi/fc_frame.h b/include/scsi/fc_frame.h
index 29dd97d5b53a..4ad02041b667 100644
--- a/include/scsi/fc_frame.h
+++ b/include/scsi/fc_frame.h
@@ -30,6 +30,23 @@
 
 #include <linux/if_ether.h>
 
+/* some helpful macros */
+
+#define ntohll(x) be64_to_cpu(x)
+#define htonll(x) cpu_to_be64(x)
+
+static inline u32 ntoh24(const u8 *p)
+{
+        return (p[0] << 16) | (p[1] << 8) | p[2];
+}
+
+static inline void hton24(u8 *p, u32 v)
+{
+        p[0] = (v >> 16) & 0xff;
+        p[1] = (v >> 8) & 0xff;
+        p[2] = v & 0xff;
+}
+
 /*
  * The fc_frame interface is used to pass frame data between functions.
  * The frame includes the data buffer, length, and SOF / EOF delimiter types.
@@ -139,13 +156,39 @@ static inline int fc_frame_is_linear(struct fc_frame *fp)
 
 /*
  * Get frame header from message in fc_frame structure.
+ * This version doesn't do a length check.
+ */
+static inline
+struct fc_frame_header *__fc_frame_header_get(const struct fc_frame *fp)
+{
+        return (struct fc_frame_header *)fr_hdr(fp);
+}
+
+/*
+ * Get frame header from message in fc_frame structure.
  * This hides a cast and provides a place to add some checking.
  */
 static inline
 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 {
         WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
-        return (struct fc_frame_header *) fr_hdr(fp);
+        return __fc_frame_header_get(fp);
+}
+
+/*
+ * Get source FC_ID (S_ID) from frame header in message.
+ */
+static inline u32 fc_frame_sid(const struct fc_frame *fp)
+{
+        return ntoh24(__fc_frame_header_get(fp)->fh_s_id);
+}
+
+/*
+ * Get destination FC_ID (D_ID) from frame header in message.
+ */
+static inline u32 fc_frame_did(const struct fc_frame *fp)
+{
+        return ntoh24(__fc_frame_header_get(fp)->fh_d_id);
 }
 
 /*