1 files changed, 76 insertions, 33 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 956496182c8..b65e65aa07e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -583,7 +583,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
 		 * quietly refuse to do anything to a changed disc until 
 		 * the changed bit has been reset
 		 */
-		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
+		/* printk("SCSI disk has been changed or is not present. Prohibiting further I/O.\n"); */
 		goto out;
 	}
 
@@ -1023,7 +1023,6 @@ static int sd_media_changed(struct gendisk *disk)
 	 */
 	if (!scsi_device_online(sdp)) {
 		set_media_not_present(sdkp);
-		retval = 1;
 		goto out;
 	}
 
@@ -1044,17 +1043,8 @@ static int sd_media_changed(struct gendisk *disk)
 					      sshdr);
 	}
 
-	/*
-	 * Unable to test, unit probably not ready.   This usually
-	 * means there is no disc in the drive.  Mark as changed,
-	 * and we will figure it out later once the drive is
-	 * available again.
-	 */
-	if (retval || (scsi_sense_valid(sshdr) &&
-		       /* 0x3a is medium not present */
-		       sshdr->asc == 0x3a)) {
+	if (retval) {
 		set_media_not_present(sdkp);
-		retval = 1;
 		goto out;
 	}
 
@@ -1065,12 +1055,27 @@ static int sd_media_changed(struct gendisk *disk)
 	 */
 	sdkp->media_present = 1;
 
-	retval = sdp->changed;
-	sdp->changed = 0;
 out:
-	if (retval != sdkp->previous_state)
+	/*
+	 * Report a media change under the following conditions:
+	 *
+	 *	Medium is present now and wasn't present before.
+	 *	Medium wasn't present before and is present now.
+	 *	Medium was present at all times, but it changed while
+	 *		we weren't looking (sdp->changed is set).
+	 *
+	 * If there was no medium before and there is no medium now then
+	 * don't report a change, even if a medium was inserted and removed
+	 * while we weren't looking.
+	 */
+	retval = (sdkp->media_present != sdkp->previous_state ||
+			(sdkp->media_present && sdp->changed));
+	if (retval)
 		sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
-	sdkp->previous_state = retval;
+	sdkp->previous_state = sdkp->media_present;
+
+	/* sdp->changed indicates medium was changed or is not present */
+	sdp->changed = !sdkp->media_present;
 	kfree(sshdr);
 	return retval;
 }
@@ -1175,6 +1180,12 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
 	u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);
 	u64 bad_lba;
 	int info_valid;
+	/*
+	 * resid is optional but mostly filled in.  When it's unused,
+	 * its value is zero, so we assume the whole buffer transferred
+	 */
+	unsigned int transferred = scsi_bufflen(scmd) - scsi_get_resid(scmd);
+	unsigned int good_bytes;
 
 	if (scmd->request->cmd_type != REQ_TYPE_FS)
 		return 0;
@@ -1208,7 +1219,8 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
 	/* This computation should always be done in terms of
 	 * the resolution of the device's medium.
 	 */
-	return (bad_lba - start_lba) * scmd->device->sector_size;
+	good_bytes = (bad_lba - start_lba) * scmd->device->sector_size;
+	return min(good_bytes, transferred);
 }
 
 /**
@@ -1902,10 +1914,14 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 	int old_rcd = sdkp->RCD;
 	int old_dpofua = sdkp->DPOFUA;
 
-	if (sdp->skip_ms_page_8)
-		goto defaults;
-
-	if (sdp->type == TYPE_RBC) {
+	if (sdp->skip_ms_page_8) {
+		if (sdp->type == TYPE_RBC)
+			goto defaults;
+		else {
+			modepage = 0x3F;
+			dbd = 0;
+		}
+	} else if (sdp->type == TYPE_RBC) {
 		modepage = 6;
 		dbd = 8;
 	} else {
@@ -1933,13 +1949,11 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 	 */
 	if (len < 3)
 		goto bad_sense;
-	if (len > 20)
-		len = 20;
-
-	/* Take headers and block descriptors into account */
-	len += data.header_length + data.block_descriptor_length;
-	if (len > SD_BUF_SIZE)
-		goto bad_sense;
+	else if (len > SD_BUF_SIZE) {
+		sd_printk(KERN_NOTICE, sdkp, "Truncating mode parameter "
+			  "data from %d to %d bytes\n", len, SD_BUF_SIZE);
+		len = SD_BUF_SIZE;
+	}
 
 	/* Get the data */
 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
@@ -1947,16 +1961,45 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 	if (scsi_status_is_good(res)) {
 		int offset = data.header_length + data.block_descriptor_length;
 
-		if (offset >= SD_BUF_SIZE - 2) {
-			sd_printk(KERN_ERR, sdkp, "Malformed MODE SENSE response\n");
-			goto defaults;
+		while (offset < len) {
+			u8 page_code = buffer[offset] & 0x3F;
+			u8 spf       = buffer[offset] & 0x40;
+
+			if (page_code == 8 || page_code == 6) {
+				/* We're interested only in the first 3 bytes.
+				 */
+				if (len - offset <= 2) {
+					sd_printk(KERN_ERR, sdkp, "Incomplete "
+						  "mode parameter data\n");
+					goto defaults;
+				} else {
+					modepage = page_code;
+					goto Page_found;
+				}
+			} else {
+				/* Go to the next page */
+				if (spf && len - offset > 3)
+					offset += 4 + (buffer[offset+2] << 8) +
+						buffer[offset+3];
+				else if (!spf && len - offset > 1)
+					offset += 2 + buffer[offset+1];
+				else {
+					sd_printk(KERN_ERR, sdkp, "Incomplete "
+						  "mode parameter data\n");
+					goto defaults;
+				}
+			}
 		}
 
-		if ((buffer[offset] & 0x3f) != modepage) {
+		if (modepage == 0x3F) {
+			sd_printk(KERN_ERR, sdkp, "No Caching mode page "
+				  "present\n");
+			goto defaults;
+		} else if ((buffer[offset] & 0x3f) != modepage) {
 			sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
 			goto defaults;
 		}
-
+	Page_found:
 		if (modepage == 8) {
 			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
 			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);