USB: UB: Let cdrecord to see a device with media absent

The command "cdrecord dev=/dev/uba x.iso" prints nasty garbage if a blank
is not in the drive. This happens because drivers have to set req->errors
separately from just returning zero uptodate with end_that_request_first,
end_that_request_last. These functions only set error in BIO, but sg_io()
ignores it.

Since we're on it, let cdrecord access a device when ->changed is set.
It's useful if someone wants to know device capabilities without burning
anything.

Signed-Off-By: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/block/ub.c b/drivers/block/ub.c
index d62b49f..45a8f40 100644 (file)
--- a/drivers/block/ub.c
+++ b/drivers/block/ub.c
@@ -358,7 +358,7 @@ static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
-static void ub_end_rq(struct request *rq, int uptodate);
+static void ub_end_rq(struct request *rq, unsigned int status);
 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
@@ -639,9 +639,15 @@ static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
        struct ub_request *urq;
        int n_elem;
 
-       if (atomic_read(&sc->poison) || lun->changed) {
+       if (atomic_read(&sc->poison)) {
+               blkdev_dequeue_request(rq);
+               ub_end_rq(rq, DID_NO_CONNECT << 16);
+               return 0;
+       }
+
+       if (lun->changed && !blk_pc_request(rq)) {
                blkdev_dequeue_request(rq);
-               ub_end_rq(rq, 0);
+               ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
                return 0;
        }
 
@@ -693,7 +699,7 @@ static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 
 drop:
        ub_put_cmd(lun, cmd);
-       ub_end_rq(rq, 0);
+       ub_end_rq(rq, DID_ERROR << 16);
        return 0;
 }
 
@@ -761,47 +767,53 @@ static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        struct ub_lun *lun = cmd->lun;
        struct ub_request *urq = cmd->back;
        struct request *rq;
-       int uptodate;
+       unsigned int scsi_status;
 
        rq = urq->rq;
 
        if (cmd->error == 0) {
-               uptodate = 1;
-
                if (blk_pc_request(rq)) {
                        if (cmd->act_len >= rq->data_len)
                                rq->data_len = 0;
                        else
                                rq->data_len -= cmd->act_len;
                }
+               scsi_status = 0;
        } else {
-               uptodate = 0;
-
                if (blk_pc_request(rq)) {
                        /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
                        memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
                        rq->sense_len = UB_SENSE_SIZE;
                        if (sc->top_sense[0] != 0)
-                               rq->errors = SAM_STAT_CHECK_CONDITION;
+                               scsi_status = SAM_STAT_CHECK_CONDITION;
                        else
-                               rq->errors = DID_ERROR << 16;
+                               scsi_status = DID_ERROR << 16;
                } else {
                        if (cmd->error == -EIO) {
                                if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
                                        return;
                        }
+                       scsi_status = SAM_STAT_CHECK_CONDITION;
                }
        }
 
        urq->rq = NULL;
 
        ub_put_cmd(lun, cmd);
-       ub_end_rq(rq, uptodate);
+       ub_end_rq(rq, scsi_status);
        blk_start_queue(lun->disk->queue);
 }
 
-static void ub_end_rq(struct request *rq, int uptodate)
+static void ub_end_rq(struct request *rq, unsigned int scsi_status)
 {
+       int uptodate;
+
+       if (scsi_status == 0) {
+               uptodate = 1;
+       } else {
+               uptodate = 0;
+               rq->errors = scsi_status;
+       }
        end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
        end_that_request_last(rq, uptodate);
 }