[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>

1 files changed, 27 insertions, 9 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 19afb25e44d3..bb8235598787 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;