[PATCH] cciss: direct lookup for command completions
This patch changes the way we complete commands. In the old method when we
got a completion we searched our command list from the top until we find it.
This method uses a tag associated with each command (not SCSI command tagging)
to index us directly to the completed command. This helps performance.
Signed-off-by: Don Brace <dab@hp.com>
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/block/cciss_cmd.h b/drivers/block/cciss_cmd.h
index a88a888..53fea54 100644
--- a/drivers/block/cciss_cmd.h
+++ b/drivers/block/cciss_cmd.h
@@ -226,6 +226,10 @@
#define CMD_MSG_DONE 0x04
#define CMD_MSG_TIMEOUT 0x05
+/* This structure needs to be divisible by 8 for new
+ * indexing method.
+ */
+#define PADSIZE (sizeof(long) - 4)
typedef struct _CommandList_struct {
CommandListHeader_struct Header;
RequestBlock_struct Request;
@@ -236,14 +240,14 @@
ErrorInfo_struct * err_info; /* pointer to the allocated mem */
int ctlr;
int cmd_type;
+ long cmdindex;
struct _CommandList_struct *prev;
struct _CommandList_struct *next;
struct request * rq;
struct completion *waiting;
int retry_count;
-#ifdef CONFIG_CISS_SCSI_TAPE
void * scsi_cmd;
-#endif
+ char pad[PADSIZE];
} CommandList_struct;
//Configuration Table Structure