Commit 2eefd57b authored by Sujit Reddy Thumma's avatar Sujit Reddy Thumma Committed by Christoph Hellwig

sd: Avoid sending medium write commands if device is write protected

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: default avatarSujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: default avatarDolev Raviv <draviv@codeaurora.org>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarVenkatesh Srinivas <venkateshs@google.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 74cf298f
......@@ -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;
......@@ -2490,6 +2490,10 @@ 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,
......
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