hpsa: do not queue commands internally in driver

By not doing maintaining a list of queued commands, we can eliminate some spin
locking in the main i/o path and gain significant improvement in IOPS.  Remove
the queuing code and the code that calls it; remove now-unused interrupt code;
remove DIRECT_LOOKUP_BIT.

Now that the passthru commands share the same command pool as
the main i/o path, and the total size of the pool is less than
or equal to the number of commands that will fit in the hardware
fifo, there is no need to check to see if we are exceeding the
hardware fifo's depth.

Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/scsi/hpsa_cmd.h b/drivers/scsi/hpsa_cmd.h
index 9bae50cb43a2..d78e66629650 100644
--- a/drivers/scsi/hpsa_cmd.h
+++ b/drivers/scsi/hpsa_cmd.h
@@ -375,22 +375,19 @@ struct ErrorInfo {
 #define CMD_IOACCEL1	0x04
 #define CMD_IOACCEL2	0x05
 
-#define DIRECT_LOOKUP_SHIFT 5
-#define DIRECT_LOOKUP_BIT 0x10
+#define DIRECT_LOOKUP_SHIFT 4
 #define DIRECT_LOOKUP_MASK (~((1 << DIRECT_LOOKUP_SHIFT) - 1))
 
 #define HPSA_ERROR_BIT          0x02
 struct ctlr_info; /* defined in hpsa.h */
-/* The size of this structure needs to be divisible by 32
- * on all architectures because low 5 bits of the addresses
+/* The size of this structure needs to be divisible by 128
+ * on all architectures.  The low 4 bits of the addresses
  * are used as follows:
  *
  * bit 0: to device, used to indicate "performant mode" command
  *        from device, indidcates error status.
  * bit 1-3: to device, indicates block fetch table entry for
  *          reducing DMA in fetching commands from host memory.
- * bit 4: used to indicate whether tag is "direct lookup" (index),
- *        or a bus address.
  */
 
 #define COMMANDLIST_ALIGNMENT 128
@@ -405,7 +402,6 @@ struct CommandList {
 	struct ctlr_info	   *h;
 	int			   cmd_type;
 	long			   cmdindex;
-	struct list_head list;
 	struct completion *waiting;
 	void   *scsi_cmd;
 } __aligned(COMMANDLIST_ALIGNMENT);