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Commit 1a340d8b authored by Sujit Reddy Thumma's avatar Sujit Reddy Thumma
Browse files

scsi: 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.

Change-Id: I90eac425a52e22d3f6fc00b74d32497e7a998c0c
Signed-off-by: default avatarSujit Reddy Thumma <sthumma@codeaurora.org>
parent 5d0b9e82

drivers/scsi/sd.c

+5 −1
Original line number Diff line number Diff line
@@ -169,7 +169,7 @@ sd_store_cache_type(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;
@@ -2438,6 +2438,10 @@ 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,