From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dolev Raviv Subject: [PATCH/RFC V2 09/16] scsi: sd: Avoid sending medium write commands if device is write protected Date: Thu, 14 Aug 2014 16:31:00 +0300 Message-ID: <1408023067-26103-10-git-send-email-draviv@codeaurora.org> References: <1408023067-26103-1-git-send-email-draviv@codeaurora.org> Return-path: In-Reply-To: <1408023067-26103-1-git-send-email-draviv@codeaurora.org> Sender: linux-scsi-owner@vger.kernel.org To: James.Bottomley@HansenPartnership.com, hch@infradead.org Cc: linux-scsi@vger.kernel.org, linux-scsi-owner@vger.kernel.org, linux-arm-msm@vger.kernel.org, santoshsy@gmail.com, Sujit Reddy Thumma , Dolev Raviv List-Id: linux-arm-msm@vger.kernel.org From: Sujit Reddy Thumma 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 Signed-off-by: Dolev Raviv 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 -- QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation