2 files changed, 21 insertions, 0 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7992635d405f..82910cc69ba3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -142,6 +142,7 @@ sd_store_cache_type(struct device *dev, struct device_attribute *attr,
         char *buffer_data;
         struct scsi_mode_data data;
         struct scsi_sense_hdr sshdr;
+        const char *temp = "temporary ";
         int len;
 
         if (sdp->type != TYPE_DISK)
@@ -150,6 +151,13 @@ sd_store_cache_type(struct device *dev, struct device_attribute *attr,
                  * it's not worth the risk */
                 return -EINVAL;
 
+        if (strncmp(buf, temp, sizeof(temp) - 1) == 0) {
+                buf += sizeof(temp) - 1;
+                sdkp->cache_override = 1;
+        } else {
+                sdkp->cache_override = 0;
+        }
+
         for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {
                 len = strlen(sd_cache_types[i]);
                 if (strncmp(sd_cache_types[i], buf, len) == 0 &&
@@ -162,6 +170,13 @@ sd_store_cache_type(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
         rcd = ct & 0x01 ? 1 : 0;
         wce = ct & 0x02 ? 1 : 0;
+
+        if (sdkp->cache_override) {
+                sdkp->WCE = wce;
+                sdkp->RCD = rcd;
+                return count;
+        }
+
         if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
                             SD_MAX_RETRIES, &data, NULL))
                 return -EINVAL;
@@ -2319,6 +2334,10 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
         int old_rcd = sdkp->RCD;
         int old_dpofua = sdkp->DPOFUA;
 
+
+        if (sdkp->cache_override)
+                return;
+
         first_len = 4;
         if (sdp->skip_ms_page_8) {
                 if (sdp->type == TYPE_RBC)
@@ -2812,6 +2831,7 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
         sdkp->capacity = 0;
         sdkp->media_present = 1;
         sdkp->write_prot = 0;
+        sdkp->cache_override = 0;
         sdkp->WCE = 0;
         sdkp->RCD = 0;
         sdkp->ATO = 0;
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 74a1e4ca5401..2386aeb41fe8 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -73,6 +73,7 @@ struct scsi_disk {
         u8              protection_type;/* Data Integrity Field */
         u8              provisioning_mode;
         unsigned        ATO : 1;        /* state of disk ATO bit */
+        unsigned        cache_override : 1; /* temp override of WCE,RCD */
         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 */