From: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
The SYNCHRONIZE_CACHE command is a medium write command and hence can
fail when the device is write protected. Avoid sending such commands by
making sure that write-cache-enable is disabled even though the device
claim to support it.
Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3663e38..67282bf 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -185,7 +185,7 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
if (ct < 0)
return -EINVAL;
rcd = ct & 0x01 ? 1 : 0;
- wce = ct & 0x02 ? 1 : 0;
+ wce = (ct & 0x02) && !sdkp->write_prot ? 1 : 0;
if (sdkp->cache_override) {
sdkp->WCE = wce;
@@ -2493,6 +2493,10 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
sdkp->DPOFUA = 0;
}
+ /* No cache flush allowed for write protected devices */
+ if (sdkp->WCE && sdkp->write_prot)
+ sdkp->WCE = 0;
+
if (sdkp->first_scan || old_wce != sdkp->WCE ||
old_rcd != sdkp->RCD || old_dpofua != sdkp->DPOFUA)
sd_printk(KERN_NOTICE, sdkp,
--
1.8.5.2
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