1 files changed, 56 insertions, 9 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 83695b646d7f..c10125fcd35b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -208,6 +208,12 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
 	sp = buffer_data[0] & 0x80 ? 1 : 0;
 	buffer_data[0] &= ~0x80;
 
+	/*
+	 * Ensure WP, DPOFUA, and RESERVED fields are cleared in
+	 * received mode parameter buffer before doing MODE SELECT.
+	 */
+	data.device_specific = 0;
+
 	if (scsi_mode_select(sdp, 1, sp, 8, buffer_data, len, SD_TIMEOUT,
 			     SD_MAX_RETRIES, &data, &sshdr)) {
 		if (scsi_sense_valid(&sshdr))
@@ -2827,6 +2833,55 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
 		sdkp->ws10 = 1;
 }
 
+/*
+ * Determine the device's preferred I/O size for reads and writes
+ * unless the reported value is unreasonably small, large, not a
+ * multiple of the physical block size, or simply garbage.
+ */
+static bool sd_validate_opt_xfer_size(struct scsi_disk *sdkp,
+				      unsigned int dev_max)
+{
+	struct scsi_device *sdp = sdkp->device;
+	unsigned int opt_xfer_bytes =
+		logical_to_bytes(sdp, sdkp->opt_xfer_blocks);
+
+	if (sdkp->opt_xfer_blocks > dev_max) {
+		sd_first_printk(KERN_WARNING, sdkp,
+				"Optimal transfer size %u logical blocks " \
+				"> dev_max (%u logical blocks)\n",
+				sdkp->opt_xfer_blocks, dev_max);
+		return false;
+	}
+
+	if (sdkp->opt_xfer_blocks > SD_DEF_XFER_BLOCKS) {
+		sd_first_printk(KERN_WARNING, sdkp,
+				"Optimal transfer size %u logical blocks " \
+				"> sd driver limit (%u logical blocks)\n",
+				sdkp->opt_xfer_blocks, SD_DEF_XFER_BLOCKS);
+		return false;
+	}
+
+	if (opt_xfer_bytes < PAGE_SIZE) {
+		sd_first_printk(KERN_WARNING, sdkp,
+				"Optimal transfer size %u bytes < " \
+				"PAGE_SIZE (%u bytes)\n",
+				opt_xfer_bytes, (unsigned int)PAGE_SIZE);
+		return false;
+	}
+
+	if (opt_xfer_bytes & (sdkp->physical_block_size - 1)) {
+		sd_first_printk(KERN_WARNING, sdkp,
+				"Optimal transfer size %u bytes not a " \
+				"multiple of physical block size (%u bytes)\n",
+				opt_xfer_bytes, sdkp->physical_block_size);
+		return false;
+	}
+
+	sd_first_printk(KERN_INFO, sdkp, "Optimal transfer size %u bytes\n",
+			opt_xfer_bytes);
+	return true;
+}
+
 /**
  *	sd_revalidate_disk - called the first time a new disk is seen,
  *	performs disk spin up, read_capacity, etc.
@@ -2891,15 +2946,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
 	dev_max = min_not_zero(dev_max, sdkp->max_xfer_blocks);
 	q->limits.max_dev_sectors = logical_to_sectors(sdp, dev_max);
 
-	/*
-	 * Determine the device's preferred I/O size for reads and writes
-	 * unless the reported value is unreasonably small, large, or
-	 * garbage.
-	 */
-	if (sdkp->opt_xfer_blocks &&
-	    sdkp->opt_xfer_blocks <= dev_max &&
-	    sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS &&
-	    logical_to_bytes(sdp, sdkp->opt_xfer_blocks) >= PAGE_SIZE) {
+	if (sd_validate_opt_xfer_size(sdkp, dev_max)) {
 		q->limits.io_opt = logical_to_bytes(sdp, sdkp->opt_xfer_blocks);
 		rw_max = logical_to_sectors(sdp, sdkp->opt_xfer_blocks);
 	} else