[SCSI] sd: Make revalidate less chatty

sd_revalidate ends up being called several times during device setup.
With this patch we print everything during the first scan.  Subsequent
invocations will only print a message if the parameter in question has
actually changed (LUN capacity has increased, etc.).

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 38 insertions, 24 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8eebaa8c6f52..aeab5d9dff27 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1440,6 +1440,7 @@ sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
 {
         int sector_size;
         struct scsi_device *sdp = sdkp->device;
+        sector_t old_capacity = sdkp->capacity;
 
         if (sd_try_rc16_first(sdp)) {
                 sector_size = read_capacity_16(sdkp, sdp, buffer);
@@ -1531,10 +1532,11 @@ got_data:
                 string_get_size(sz, STRING_UNITS_10, cap_str_10,
                                 sizeof(cap_str_10));
 
-                sd_printk(KERN_NOTICE, sdkp,
-                          "%llu %d-byte hardware sectors: (%s/%s)\n",
-                          (unsigned long long)sdkp->capacity,
-                          sector_size, cap_str_10, cap_str_2);
+                if (sdkp->first_scan || old_capacity != sdkp->capacity)
+                        sd_printk(KERN_NOTICE, sdkp,
+                                  "%llu %d-byte hardware sectors: (%s/%s)\n",
+                                  (unsigned long long)sdkp->capacity,
+                                  sector_size, cap_str_10, cap_str_2);
         }
 
         /* Rescale capacity to 512-byte units */
@@ -1571,6 +1573,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)
         int res;
         struct scsi_device *sdp = sdkp->device;
         struct scsi_mode_data data;
+        int old_wp = sdkp->write_prot;
 
         set_disk_ro(sdkp->disk, 0);
         if (sdp->skip_ms_page_3f) {
@@ -1611,11 +1614,13 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)
         } else {
                 sdkp->write_prot = ((data.device_specific & 0x80) != 0);
                 set_disk_ro(sdkp->disk, sdkp->write_prot);
-                sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
-                          sdkp->write_prot ? "on" : "off");
-                sd_printk(KERN_DEBUG, sdkp,
-                          "Mode Sense: %02x %02x %02x %02x\n",
-                          buffer[0], buffer[1], buffer[2], buffer[3]);
+                if (sdkp->first_scan || old_wp != sdkp->write_prot) {
+                        sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
+                                  sdkp->write_prot ? "on" : "off");
+                        sd_printk(KERN_DEBUG, sdkp,
+                                  "Mode Sense: %02x %02x %02x %02x\n",
+                                  buffer[0], buffer[1], buffer[2], buffer[3]);
+                }
         }
 }
 
@@ -1633,6 +1638,9 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
         int modepage;
         struct scsi_mode_data data;
         struct scsi_sense_hdr sshdr;
+        int old_wce = sdkp->WCE;
+        int old_rcd = sdkp->RCD;
+        int old_dpofua = sdkp->DPOFUA;
 
         if (sdp->skip_ms_page_8)
                 goto defaults;
@@ -1704,12 +1712,14 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
                         sdkp->DPOFUA = 0;
                 }
 
-                sd_printk(KERN_NOTICE, sdkp,
-                       "Write cache: %s, read cache: %s, %s\n",
-                       sdkp->WCE ? "enabled" : "disabled",
-                       sdkp->RCD ? "disabled" : "enabled",
-                       sdkp->DPOFUA ? "supports DPO and FUA"
-                       : "doesn't support DPO or FUA");
+                if (sdkp->first_scan || old_wce != sdkp->WCE ||
+                    old_rcd != sdkp->RCD || old_dpofua != sdkp->DPOFUA)
+                        sd_printk(KERN_NOTICE, sdkp,
+                                  "Write cache: %s, read cache: %s, %s\n",
+                                  sdkp->WCE ? "enabled" : "disabled",
+                                  sdkp->RCD ? "disabled" : "enabled",
+                                  sdkp->DPOFUA ? "supports DPO and FUA"
+                                  : "doesn't support DPO or FUA");
 
                 return;
         }
@@ -1805,15 +1815,6 @@ static int sd_revalidate_disk(struct gendisk *disk)
                 goto out;
         }
 
-        /* defaults, until the device tells us otherwise */
-        sdp->sector_size = 512;
-        sdkp->capacity = 0;
-        sdkp->media_present = 1;
-        sdkp->write_prot = 0;
-        sdkp->WCE = 0;
-        sdkp->RCD = 0;
-        sdkp->ATO = 0;
-
         sd_spinup_disk(sdkp);
 
         /*
@@ -1827,6 +1828,8 @@ static int sd_revalidate_disk(struct gendisk *disk)
                 sd_read_app_tag_own(sdkp, buffer);
         }
 
+        sdkp->first_scan = 0;
+
         /*
          * We now have all cache related info, determine how we deal
          * with ordered requests.  Note that as the current SCSI
@@ -1937,6 +1940,16 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
         gd->private_data = &sdkp->driver;
         gd->queue = sdkp->device->request_queue;
 
+        /* defaults, until the device tells us otherwise */
+        sdp->sector_size = 512;
+        sdkp->capacity = 0;
+        sdkp->media_present = 1;
+        sdkp->write_prot = 0;
+        sdkp->WCE = 0;
+        sdkp->RCD = 0;
+        sdkp->ATO = 0;
+        sdkp->first_scan = 1;
+
         sd_revalidate_disk(gd);
 
         blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 75638e7d3f66..708778cf5f06 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -53,6 +53,7 @@ struct scsi_disk {
         unsigned        WCE : 1;        /* state of disk WCE bit */
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */
         unsigned        DPOFUA : 1;     /* state of disk DPOFUA bit */
+        unsigned        first_scan : 1;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)