[SCSI] aacraid: add parameter to control FUA and SYNCHRONIZE_CACHE policy

aacraid.cache parameter, Disable Queue Flush commands:
        bit 0 - Disable FUA in WRITE SCSI commands
        bit 1 - Disable SYNCHRONIZE_CACHE SCSI command
        bit 2 - Disable only if Battery not protecting adapter supplied Cache

e.g.: aacraid.cache=7 will disable the FUA and SYNCHRONIZE_CACHE
commands if the adapter has reported that it's cache is battery backed
up.

This parameter permits experimentation with tradeoffs between
performance and caching policy.

Signed-off-by: Mark Salyzyn <aacraid@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

3 files changed, 30 insertions, 12 deletions

diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
index cef764eba307..43d6aff460d2 100644
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -144,6 +144,7 @@ static char *aac_get_status_string(u32 status);
  */     
  
 static int nondasd = -1;
+static int aac_cache = 0;
 static int dacmode = -1;
 
 int aac_commit = -1;
@@ -152,6 +153,8 @@ int aif_timeout = 120;
 
 module_param(nondasd, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(nondasd, "Control scanning of hba for nondasd devices. 0=off, 1=on");
+module_param_named(cache, aac_cache, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(cache, "Disable Queue Flush commands:\n\tbit 0 - Disable FUA in WRITE SCSI commands\n\tbit 1 - Disable SYNCHRONIZE_CACHE SCSI command\n\tbit 2 - Disable only if Battery not protecting Cache");
 module_param(dacmode, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(dacmode, "Control whether dma addressing is using 64 bit DAC. 0=off, 1=on");
 module_param_named(commit, aac_commit, int, S_IRUGO|S_IWUSR);
@@ -1013,7 +1016,8 @@ static int aac_write_raw_io(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u
         writecmd->block[1] = cpu_to_le32((u32)((lba&0xffffffff00000000LL)>>32));
         writecmd->count = cpu_to_le32(count<<9);
         writecmd->cid = cpu_to_le16(scmd_id(cmd));
-        writecmd->flags = fua ?
+        writecmd->flags = (fua && ((aac_cache & 5) != 1) &&
+          (((aac_cache & 5) != 5) || !fib->dev->cache_protected)) ?
                 cpu_to_le16(IO_TYPE_WRITE|IO_SUREWRITE) :
                 cpu_to_le16(IO_TYPE_WRITE);
         writecmd->bpTotal = 0;
@@ -1325,11 +1329,11 @@ int aac_get_adapter_info(struct aac_dev* dev)
                 }
         }
 
+        dev->cache_protected = 0;
         dev->nondasd_support = 0;
         dev->raid_scsi_mode = 0;
-        if(dev->adapter_info.options & AAC_OPT_NONDASD){
+        if(dev->adapter_info.options & AAC_OPT_NONDASD)
                 dev->nondasd_support = 1;
-        }
 
         /*
          * If the firmware supports ROMB RAID/SCSI mode and we are currently
@@ -1351,10 +1355,9 @@ int aac_get_adapter_info(struct aac_dev* dev)
                 printk(KERN_INFO "%s%d: ROMB RAID/SCSI mode enabled\n",
                                 dev->name, dev->id);
                 
-        if(nondasd != -1) {  
+        if (nondasd != -1)
                 dev->nondasd_support = (nondasd!=0);
-        }
-        if(dev->nondasd_support != 0){
+        if(dev->nondasd_support != 0) {
                 printk(KERN_INFO "%s%d: Non-DASD support enabled.\n",dev->name, dev->id);
         }
 
@@ -2106,7 +2109,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                 mode_buf[2] = 0;        /* Device-specific param,
                                            bit 8: 0/1 = write enabled/protected
                                            bit 4: 0/1 = FUA enabled */
-                if (dev->raw_io_interface)
+                if (dev->raw_io_interface && ((aac_cache & 5) != 1))
                         mode_buf[2] = 0x10;
                 mode_buf[3] = 0;        /* Block descriptor length */
                 if (((scsicmd->cmnd[2] & 0x3f) == 8) ||
@@ -2114,7 +2117,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                         mode_buf[0] = 6;
                         mode_buf[4] = 8;
                         mode_buf[5] = 1;
-                        mode_buf[6] = 0x04; /* WCE */
+                        mode_buf[6] = ((aac_cache & 6) == 2)
+                                ? 0 : 0x04; /* WCE */
                         mode_buf_length = 7;
                         if (mode_buf_length > scsicmd->cmnd[4])
                                 mode_buf_length = scsicmd->cmnd[4];
@@ -2137,7 +2141,7 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                 mode_buf[3] = 0;        /* Device-specific param,
                                            bit 8: 0/1 = write enabled/protected
                                            bit 4: 0/1 = FUA enabled */
-                if (dev->raw_io_interface)
+                if (dev->raw_io_interface && ((aac_cache & 5) != 1))
                         mode_buf[3] = 0x10;
                 mode_buf[4] = 0;        /* reserved */
                 mode_buf[5] = 0;        /* reserved */
@@ -2148,7 +2152,8 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                         mode_buf[1] = 9;
                         mode_buf[8] = 8;
                         mode_buf[9] = 1;
-                        mode_buf[10] = 0x04; /* WCE */
+                        mode_buf[10] = ((aac_cache & 6) == 2)
+                                ? 0 : 0x04; /* WCE */
                         mode_buf_length = 11;
                         if (mode_buf_length > scsicmd->cmnd[8])
                                 mode_buf_length = scsicmd->cmnd[8];
@@ -2224,9 +2229,16 @@ int aac_scsi_cmd(struct scsi_cmnd * scsicmd)
                         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 */
-                        return aac_synchronize(scsicmd);
-                        
+                        if ((aac_cache & 6) != 2)
+                                return aac_synchronize(scsicmd);
+                        /* FALLTHRU */
                 default:
                         /*
                          *      Unhandled commands
diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h
index 734623af9c45..7bb3d9fde713 100644
--- a/drivers/scsi/aacraid/aacraid.h
+++ b/drivers/scsi/aacraid/aacraid.h
@@ -1016,6 +1016,7 @@ struct aac_dev
          * lets break them out so we don't have to do an AND to check them
          */
         u8                      nondasd_support; 
+        u8                      cache_protected;
         u8                      dac_support;
         u8                      raid_scsi_mode;
         u8                      comm_interface;
@@ -1770,6 +1771,7 @@ extern struct aac_common aac_config;
 #define                 AifEnConfigChange       3       /* Adapter configuration change */
 #define                 AifEnContainerChange    4       /* Container configuration change */
 #define                 AifEnDeviceFailure      5       /* SCSI device failed */
+#define                 AifEnBatteryEvent       14      /* Change in Battery State */
 #define                 AifEnAddContainer       15      /* A new array was created */
 #define                 AifEnDeleteContainer    16      /* A container was deleted */
 #define                 AifEnExpEvent           23      /* Firmware Event Log */
diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c
index 53d415e812ee..81cdac166d4b 100644
--- a/drivers/scsi/aacraid/commsup.c
+++ b/drivers/scsi/aacraid/commsup.c
@@ -849,6 +849,10 @@ static void aac_handle_aif(struct aac_dev * dev, struct fib * fibptr)
 
         case AifCmdEventNotify:
                 switch (le32_to_cpu(((__le32 *)aifcmd->data)[0])) {
+                case AifEnBatteryEvent:
+                        dev->cache_protected =
+                                (((__le32 *)aifcmd->data)[1] == cpu_to_le32(3));
+                        break;
                 /*
                  *      Add an Array.
                  */