[SCSI] TYPE_RBC cache fixes (sbp2.c affected)

	a) TYPE_SDAD renamed to TYPE_RBC and taken to scsi.h
	b) in sbp2.c remapping of TYPE_RPB to TYPE_DISK turned off
	c) relevant places in midlayer and sd.c taught to accept TYPE_RBC
	d) sd.c::sd_read_cache_type() looks into page 6 when dealing with
TYPE_RBC - these guys have writeback cache flag there and are not guaranteed
to have page 8 at all.
	e) sd_read_cache_type() got an extra sanity check - it checks that
it got the page it asked for before using its contents.  And screams if
mismatch had happened.  Rationale: there are broken devices out there that
are "helpful" enough to go for "I don't have a page you've asked for, here,
have another one".  For example, PL3507 had been caught doing just that...
	f) sbp2 sets sdev->use_10_for_rw and sdev->use_10_for_ms instead
of bothering to remap READ6/WRITE6/MOD_SENSE, so most of the conversions
in there are gone now.

	Incidentally, I wonder if USB storage devices that have no
mode page 8 are simply RBC ones.  I haven't touched that, but it might
be interesting to check...

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 28 insertions, 9 deletions

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index cca7726..5886115 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -625,6 +625,7 @@ static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
 	case TYPE_MEDIUM_CHANGER:
 	case TYPE_ENCLOSURE:
 	case TYPE_COMM:
+	case TYPE_RBC:
 		sdev->writeable = 1;
 		break;
 	case TYPE_WORM:
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 19afb25..bb823559 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1368,17 +1368,26 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
  */
 static void
 sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
-		   struct scsi_request *SRpnt, unsigned char *buffer) {
+		   struct scsi_request *SRpnt, unsigned char *buffer)
+{
 	int len = 0, res;
 
-	const int dbd = 0;	   /* DBD */
-	const int modepage = 0x08; /* current values, cache page */
+	int dbd;
+	int modepage;
 	struct scsi_mode_data data;
 	struct scsi_sense_hdr sshdr;
 
 	if (sdkp->device->skip_ms_page_8)
 		goto defaults;
 
+	if (sdkp->device->type == TYPE_RBC) {
+		modepage = 6;
+		dbd = 8;
+	} else {
+		modepage = 8;
+		dbd = 0;
+	}
+
 	/* cautiously ask */
 	res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, 4, &data);
 
@@ -1409,11 +1418,20 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
 			"write back, no read (daft)"
 		};
 		int ct = 0;
-		int offset = data.header_length +
-			data.block_descriptor_length + 2;
+		int offset = data.header_length + data.block_descriptor_length;
 
-		sdkp->WCE = ((buffer[offset] & 0x04) != 0);
-		sdkp->RCD = ((buffer[offset] & 0x01) != 0);
+		if ((buffer[offset] & 0x3f) != modepage) {
+			printk(KERN_ERR "%s: got wrong page\n", diskname);
+			goto defaults;
+		}
+
+		if (modepage == 8) {
+			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
+			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
+		} else {
+			sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
+			sdkp->RCD = 0;
+		}
 
 		ct =  sdkp->RCD + 2*sdkp->WCE;
 
@@ -1533,7 +1551,7 @@ static int sd_probe(struct device *dev)
 	int error;
 
 	error = -ENODEV;
-	if ((sdp->type != TYPE_DISK) && (sdp->type != TYPE_MOD))
+	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
 		goto out;
 
 	SCSI_LOG_HLQUEUE(3, printk("sd_attach: scsi device: <%d,%d,%d,%d>\n", 
@@ -1570,7 +1588,7 @@ static int sd_probe(struct device *dev)
 	sdkp->openers = 0;
 
 	if (!sdp->timeout) {
-		if (sdp->type == TYPE_DISK)
+		if (sdp->type != TYPE_MOD)
 			sdp->timeout = SD_TIMEOUT;
 		else
 			sdp->timeout = SD_MOD_TIMEOUT;