block: unify request timeout handling

Right now SCSI and others do their own command timeout handling.
Move those bits to the block layer.

Instead of having a timer per command, we try to be a bit more clever
and simply have one per-queue. This avoids the overhead of having to
tear down and setup a timer for each command, so it will result in a lot
less timer fiddling.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index 461331d..81c16cb 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -612,7 +612,7 @@
 	pc->req_xfer = pc->buf_size = scsi_bufflen(cmd);
 	pc->scsi_cmd = cmd;
 	pc->done = done;
-	pc->timeout = jiffies + cmd->timeout_per_command;
+	pc->timeout = jiffies + cmd->request->timeout;
 
 	if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
 		printk ("ide-scsi: %s: que %lu, cmd = ", drive->name, cmd->serial_number);