scsi: aacraid: Reworked scsi command submission path

Moved the READ and WRITE switch cases to the top. Added a  default
case to the switch case and replaced duplicate scsi result value with a
macro.

The idea is that since most of scsi commands we care about performance
wise are read or write, we need to process them first.

Internally the compiler (GCC) converts a switch case into either a jump
table or a bunch of if else conditions, so placing the often used read,
write cases at the top is an effort in optimization.

Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: Dave Carroll <David.Carroll@microsemi.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
index bd5c80f..8d8e6c2 100644 (file)
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -106,6 +106,8 @@
 #define ASENCODE_LUN_FAILED_SELF_CONFIG                0x00
 #define ASENCODE_OVERLAPPED_COMMAND            0x00
 
+#define AAC_STAT_GOOD (DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD)
+
 #define BYTE0(x) (unsigned char)(x)
 #define BYTE1(x) (unsigned char)((x) >> 8)
 #define BYTE2(x) (unsigned char)((x) >> 16)
@@ -2476,8 +2478,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                        if((cid >= dev->maximum_num_containers) ||
                                        (scsicmd->device->lun != 0)) {
                                scsicmd->result = DID_NO_CONNECT << 16;
-                               scsicmd->scsi_done(scsicmd);
-                               return 0;
+                               goto scsi_done_ret;
                        }
 
                        /*
@@ -2512,8 +2513,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                return aac_send_srb_fib(scsicmd);
                        } else {
                                scsicmd->result = DID_NO_CONNECT << 16;
-                               scsicmd->scsi_done(scsicmd);
-                               return 0;
+                               goto scsi_done_ret;
                        }
                }
        }
@@ -2531,13 +2531,34 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                memcpy(scsicmd->sense_buffer, &dev->fsa_dev[cid].sense_data,
                       min_t(size_t, sizeof(dev->fsa_dev[cid].sense_data),
                             SCSI_SENSE_BUFFERSIZE));
-               scsicmd->scsi_done(scsicmd);
-               return 0;
+               goto scsi_done_ret;
        }
 
-
-       /* Handle commands here that don't really require going out to the adapter */
        switch (scsicmd->cmnd[0]) {
+       case READ_6:
+       case READ_10:
+       case READ_12:
+       case READ_16:
+               if (dev->in_reset)
+                       return -1;
+               return aac_read(scsicmd);
+
+       case WRITE_6:
+       case WRITE_10:
+       case WRITE_12:
+       case WRITE_16:
+               if (dev->in_reset)
+                       return -1;
+               return aac_write(scsicmd);
+
+       case SYNCHRONIZE_CACHE:
+               if (((aac_cache & 6) == 6) && dev->cache_protected) {
+                       scsicmd->result = AAC_STAT_GOOD;
+                       break;
+               }
+               /* Issue FIB to tell Firmware to flush it's cache */
+               if ((aac_cache & 6) != 2)
+                       return aac_synchronize(scsicmd);
        case INQUIRY:
        {
                struct inquiry_data inq_data;
@@ -2560,8 +2581,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                arr[1] = scsicmd->cmnd[2];
                                scsi_sg_copy_from_buffer(scsicmd, &inq_data,
                                                         sizeof(inq_data));
-                               scsicmd->result = DID_OK << 16 |
-                                 COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
+                               scsicmd->result = AAC_STAT_GOOD;
                        } else if (scsicmd->cmnd[2] == 0x80) {
                                /* unit serial number page */
                                arr[3] = setinqserial(dev, &arr[4],
@@ -2572,8 +2592,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                if (aac_wwn != 2)
                                        return aac_get_container_serial(
                                                scsicmd);
-                               scsicmd->result = DID_OK << 16 |
-                                 COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
+                               scsicmd->result = AAC_STAT_GOOD;
                        } else if (scsicmd->cmnd[2] == 0x83) {
                                /* vpd page 0x83 - Device Identification Page */
                                char *sno = (char *)&inq_data;
@@ -2582,8 +2601,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                if (aac_wwn != 2)
                                        return aac_get_container_serial(
                                                scsicmd);
-                               scsicmd->result = DID_OK << 16 |
-                                 COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
+                               scsicmd->result = AAC_STAT_GOOD;
                        } else {
                                /* vpd page not implemented */
                                scsicmd->result = DID_OK << 16 |
@@ -2598,8 +2616,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                        sizeof(dev->fsa_dev[cid].sense_data),
                                        SCSI_SENSE_BUFFERSIZE));
                        }
-                       scsicmd->scsi_done(scsicmd);
-                       return 0;
+                       break;
                }
                inq_data.inqd_ver = 2;  /* claim compliance to SCSI-2 */
                inq_data.inqd_rdf = 2;  /* A response data format value of two indicates that the data shall be in the format specified in SCSI-2 */
@@ -2615,9 +2632,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                        inq_data.inqd_pdt = INQD_PDT_PROC;      /* Processor device */
                        scsi_sg_copy_from_buffer(scsicmd, &inq_data,
                                                 sizeof(inq_data));
-                       scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-                       scsicmd->scsi_done(scsicmd);
-                       return 0;
+                       scsicmd->result = AAC_STAT_GOOD;
+                       break;
                }
                if (dev->in_reset)
                        return -1;
@@ -2665,10 +2681,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                /* Do not cache partition table for arrays */
                scsicmd->device->removable = 1;
 
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
        }
 
        case READ_CAPACITY:
@@ -2693,11 +2707,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                scsi_sg_copy_from_buffer(scsicmd, cp, sizeof(cp));
                /* Do not cache partition table for arrays */
                scsicmd->device->removable = 1;
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 |
-                 SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
        }
 
        case MODE_SENSE:
@@ -2775,10 +2786,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                scsi_sg_copy_from_buffer(scsicmd,
                                         (char *)&mpd,
                                         mode_buf_length);
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
        }
        case MODE_SENSE_10:
        {
@@ -2854,18 +2863,17 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                                         (char *)&mpd10,
                                         mode_buf_length);
 
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
        }
        case REQUEST_SENSE:
                dprintk((KERN_DEBUG "REQUEST SENSE command.\n"));
-               memcpy(scsicmd->sense_buffer, &dev->fsa_dev[cid].sense_data, sizeof (struct sense_data));
-               memset(&dev->fsa_dev[cid].sense_data, 0, sizeof (struct sense_data));
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-               return 0;
+               memcpy(scsicmd->sense_buffer, &dev->fsa_dev[cid].sense_data,
+                               sizeof(struct sense_data));
+               memset(&dev->fsa_dev[cid].sense_data, 0,
+                               sizeof(struct sense_data));
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
 
        case ALLOW_MEDIUM_REMOVAL:
                dprintk((KERN_DEBUG "LOCK command.\n"));
@@ -2874,9 +2882,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                else
                        fsa_dev_ptr[cid].locked = 0;
 
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
        /*
         *      These commands are all No-Ops
         */
@@ -2892,80 +2899,41 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                               min_t(size_t,
                                     sizeof(dev->fsa_dev[cid].sense_data),
                                     SCSI_SENSE_BUFFERSIZE));
-                       scsicmd->scsi_done(scsicmd);
-                       return 0;
+               break;
                }
-               /* FALLTHRU */
        case RESERVE:
        case RELEASE:
        case REZERO_UNIT:
        case REASSIGN_BLOCKS:
        case SEEK_10:
-               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-               scsicmd->scsi_done(scsicmd);
-               return 0;
+               scsicmd->result = AAC_STAT_GOOD;
+               break;
 
        case START_STOP:
                return aac_start_stop(scsicmd);
-       }
 
-       switch (scsicmd->cmnd[0])
-       {
-               case READ_6:
-               case READ_10:
-               case READ_12:
-               case READ_16:
-                       if (dev->in_reset)
-                               return -1;
-                       /*
-                        *      Hack to keep track of ordinal number of the device that
-                        *      corresponds to a container. Needed to convert
-                        *      containers to /dev/sd device names
-                        */
-
-                       if (scsicmd->request->rq_disk)
-                               strlcpy(fsa_dev_ptr[cid].devname,
-                               scsicmd->request->rq_disk->disk_name,
-                               min(sizeof(fsa_dev_ptr[cid].devname),
-                               sizeof(scsicmd->request->rq_disk->disk_name) + 1));
-
-                       return aac_read(scsicmd);
-
-               case WRITE_6:
-               case WRITE_10:
-               case WRITE_12:
-               case WRITE_16:
-                       if (dev->in_reset)
-                               return -1;
-                       return aac_write(scsicmd);
-
-               case SYNCHRONIZE_CACHE:
-                       if (((aac_cache & 6) == 6) && dev->cache_protected) {
-                               scsicmd->result = DID_OK << 16 |
-                                       COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
-                               scsicmd->scsi_done(scsicmd);
-                               return 0;
-                       }
-                       /* Issue FIB to tell Firmware to flush it's cache */
-                       if ((aac_cache & 6) != 2)
-                               return aac_synchronize(scsicmd);
-                       /* FALLTHRU */
-               default:
-                       /*
-                        *      Unhandled commands
-                        */
-                       dprintk((KERN_WARNING "Unhandled SCSI Command: 0x%x.\n", scsicmd->cmnd[0]));
-                       scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_CHECK_CONDITION;
-                       set_sense(&dev->fsa_dev[cid].sense_data,
+       /* FALLTHRU */
+       default:
+       /*
+        *      Unhandled commands
+        */
+               dprintk((KERN_WARNING "Unhandled SCSI Command: 0x%x.\n",
+                               scsicmd->cmnd[0]));
+               scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 |
+                               SAM_STAT_CHECK_CONDITION;
+               set_sense(&dev->fsa_dev[cid].sense_data,
                          ILLEGAL_REQUEST, SENCODE_INVALID_COMMAND,
                          ASENCODE_INVALID_COMMAND, 0, 0);
-                       memcpy(scsicmd->sense_buffer, &dev->fsa_dev[cid].sense_data,
+               memcpy(scsicmd->sense_buffer, &dev->fsa_dev[cid].sense_data,
                                min_t(size_t,
                                      sizeof(dev->fsa_dev[cid].sense_data),
                                      SCSI_SENSE_BUFFERSIZE));
-                       scsicmd->scsi_done(scsicmd);
-                       return 0;
        }
+
+scsi_done_ret:
+
+       scsicmd->scsi_done(scsicmd);
+       return 0;
 }
 
 static int query_disk(struct aac_dev *dev, void __user *arg)