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>

1 files changed, 25 insertions, 13 deletions

diff --git a/drivers/block/ub.c b/drivers/block/ub.c
index d62b49fbf10c..45a8f402b07b 100644
--- 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);
 }