SCSI: Fix problems with non-power-of-two sector size discs

We can't support them, but the system should disable them cleanly
and continue when they're detected (at the moment it
dumps a stack trace).

The fix (hack) is to set them to zero size and 512 byte
sectors.  This means they're still amenable to ioctls (like
to reformat them with a useful block size) but cannot
be read from or written to.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsicam.c

@@ -29,10 +29,11 @@ unsigned char *scsi_bios_ptable(struct block_device *dev)
 	unsigned char *res = kmalloc(66, GFP_KERNEL);
 	if (res) {
 		struct block_device *bdev = dev->bd_contains;
-		struct buffer_head *bh = __bread(bdev, 0, block_size(bdev));
-		if (bh) {
-			memcpy(res, bh->b_data + 0x1be, 66);
-			brelse(bh);
+		Sector sect;
+		void *data = read_dev_sector(bdev, 0, &sect);
+		if (data) {
+			memcpy(res, data + 0x1be, 66);
+			put_dev_sector(sect);
 		} else {
 			kfree(res);
 			res = NULL;

drivers/scsi/sd.c

@@ -1125,6 +1125,13 @@ sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 		 * For this reason, we leave the thing in the table.
 		 */
 		sdkp->capacity = 0;
+		/*
+		 * set a bogus sector size so the normal read/write
+		 * logic in the block layer will eventually refuse any
+		 * request on this device without tripping over power
+		 * of two sector size assumptions
+		 */
+		sector_size = 512;
 	}
 	{
 		/*