On Tue, Jan 30, 2007 at 08:53:19PM +0100, Luca Tettamanti wrote:
> Hi,
> pktcdvd on kernel 2.6.20-rc6 is not working as expected. Any file that
> is written to the device is lost after umount.
> I rarely use pktcdvd but at some point it used to work on my system.
> 
> This is what I'm doing:
> 
> [EMAIL PROTECTED]:/tmp# cdrwtool -d /dev/scd0 -q
> using device /dev/scd0
> 1029KB internal buffer
> setting write speed to 12x
> Settings for /dev/scd0:
>         Fixed packets, size 32
>         Mode-2 disc
>...

Does 2.6.20-rc7 work?
If no, does it work after applying the attached patch?
If no, does 2.6.19.2 work?

> Luca

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 6246219..7c95c76 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -765,34 +765,47 @@ static inline struct bio *pkt_get_list_first(struct bio 
**list_head, struct bio
  */
 static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command 
*cgc)
 {
-       request_queue_t *q = bdev_get_queue(pd->bdev);
+       char sense[SCSI_SENSE_BUFFERSIZE];
+       request_queue_t *q;
        struct request *rq;
-       int ret = 0;
-
-       rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
-                            WRITE : READ, __GFP_WAIT);
-
-       if (cgc->buflen) {
-               if (blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen, 
__GFP_WAIT))
-                       goto out;
-       }
+       DECLARE_COMPLETION_ONSTACK(wait);
+       int err = 0;
 
-       rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
-       memcpy(rq->cmd, cgc->cmd, CDROM_PACKET_SIZE);
-       if (sizeof(rq->cmd) > CDROM_PACKET_SIZE)
-               memset(rq->cmd + CDROM_PACKET_SIZE, 0, sizeof(rq->cmd) - 
CDROM_PACKET_SIZE);
+       q = bdev_get_queue(pd->bdev);
 
+       rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ? WRITE 
: READ,
+                            __GFP_WAIT);
+       rq->errors = 0;
+       rq->rq_disk = pd->bdev->bd_disk;
+       rq->bio = NULL;
+       rq->buffer = NULL;
        rq->timeout = 60*HZ;
+       rq->data = cgc->buffer;
+       rq->data_len = cgc->buflen;
+       rq->sense = sense;
+       memset(sense, 0, sizeof(sense));
+       rq->sense_len = 0;
        rq->cmd_type = REQ_TYPE_BLOCK_PC;
        rq->cmd_flags |= REQ_HARDBARRIER;
        if (cgc->quiet)
                rq->cmd_flags |= REQ_QUIET;
+       memcpy(rq->cmd, cgc->cmd, CDROM_PACKET_SIZE);
+       if (sizeof(rq->cmd) > CDROM_PACKET_SIZE)
+               memset(rq->cmd + CDROM_PACKET_SIZE, 0, sizeof(rq->cmd) - 
CDROM_PACKET_SIZE);
+       rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+       rq->ref_count++;
+       rq->end_io_data = &wait;
+       rq->end_io = blk_end_sync_rq;
+       elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 1);
+       generic_unplug_device(q);
+       wait_for_completion(&wait);
+
+       if (rq->errors)
+               err = -EIO;
 
-       blk_execute_rq(rq->q, pd->bdev->bd_disk, rq, 0);
-       ret = rq->errors;
-out:
        blk_put_request(rq);
-       return ret;
+       return err;
 }
 
 /*
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f02f48a..6fe1e82 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -998,14 +998,25 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
        int                count;
 
        /*
-        * We used to not use scatter-gather for single segment request,
+        * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
+        */
+       if (blk_pc_request(req) && !req->bio) {
+               cmd->request_bufflen = req->data_len;
+               cmd->request_buffer = req->data;
+               req->buffer = req->data;
+               cmd->use_sg = 0;
+               return 0;
+       }
+
+       /*
+        * we used to not use scatter-gather for single segment request,
         * but now we do (it makes highmem I/O easier to support without
         * kmapping pages)
         */
        cmd->use_sg = req->nr_phys_segments;
 
        /*
-        * If sg table allocation fails, requeue request later.
+        * if sg table allocation fails, requeue request later.
         */
        sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
        if (unlikely(!sgpnt)) {
@@ -1013,21 +1024,24 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
                return BLKPREP_DEFER;
        }
 
-       req->buffer = NULL;
        cmd->request_buffer = (char *) sgpnt;
+       cmd->request_bufflen = req->nr_sectors << 9;
        if (blk_pc_request(req))
                cmd->request_bufflen = req->data_len;
-       else
-               cmd->request_bufflen = req->nr_sectors << 9;
+       req->buffer = NULL;
 
        /* 
         * Next, walk the list, and fill in the addresses and sizes of
         * each segment.
         */
        count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
+
+       /*
+        * mapped well, send it off
+        */
        if (likely(count <= cmd->use_sg)) {
                cmd->use_sg = count;
-               return BLKPREP_OK;
+               return 0;
        }
 
        printk(KERN_ERR "Incorrect number of segments after building list\n");
@@ -1057,27 +1071,6 @@ static int scsi_issue_flush_fn(request_queue_t *q, 
struct gendisk *disk,
        return -EOPNOTSUPP;
 }
 
-static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
-               struct request *req)
-{
-       struct scsi_cmnd *cmd;
-
-       if (!req->special) {
-               cmd = scsi_get_command(sdev, GFP_ATOMIC);
-               if (unlikely(!cmd))
-                       return NULL;
-               req->special = cmd;
-       } else {
-               cmd = req->special;
-       }
-
-       /* pull a tag out of the request if we have one */
-       cmd->tag = req->tag;
-       cmd->request = req;
-
-       return cmd;
-}
-
 static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
 {
        BUG_ON(!blk_pc_request(cmd->request));
@@ -1090,37 +1083,9 @@ static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
        scsi_io_completion(cmd, cmd->request_bufflen);
 }
 
-static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request 
*req)
+static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd)
 {
-       struct scsi_cmnd *cmd;
-
-       cmd = scsi_get_cmd_from_req(sdev, req);
-       if (unlikely(!cmd))
-               return BLKPREP_DEFER;
-
-       /*
-        * BLOCK_PC requests may transfer data, in which case they must
-        * a bio attached to them.  Or they might contain a SCSI command
-        * that does not transfer data, in which case they may optionally
-        * submit a request without an attached bio.
-        */
-       if (req->bio) {
-               int ret;
-
-               BUG_ON(!req->nr_phys_segments);
-
-               ret = scsi_init_io(cmd);
-               if (unlikely(ret))
-                       return ret;
-       } else {
-               BUG_ON(req->data_len);
-               BUG_ON(req->data);
-
-               cmd->request_bufflen = 0;
-               cmd->request_buffer = NULL;
-               cmd->use_sg = 0;
-               req->buffer = NULL;
-       }
+       struct request *req = cmd->request;
 
        BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
        memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
@@ -1136,138 +1101,154 @@ static int scsi_setup_blk_pc_cmnd(struct scsi_device 
*sdev, struct request *req)
        cmd->allowed = req->retries;
        cmd->timeout_per_command = req->timeout;
        cmd->done = scsi_blk_pc_done;
-       return BLKPREP_OK;
-}
-
-/*
- * Setup a REQ_TYPE_FS command.  These are simple read/write request
- * from filesystems that still need to be translated to SCSI CDBs from
- * the ULD.
- */
-static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
-{
-       struct scsi_cmnd *cmd;
-       struct scsi_driver *drv;
-       int ret;
-
-       /*
-        * Filesystem requests must transfer data.
-        */
-       BUG_ON(!req->nr_phys_segments);
-
-       cmd = scsi_get_cmd_from_req(sdev, req);
-       if (unlikely(!cmd))
-               return BLKPREP_DEFER;
-
-       ret = scsi_init_io(cmd);
-       if (unlikely(ret))
-               return ret;
-
-       /*
-        * Initialize the actual SCSI command for this request.
-        */
-       drv = *(struct scsi_driver **)req->rq_disk->private_data;
-       if (unlikely(!drv->init_command(cmd))) {
-               scsi_release_buffers(cmd);
-               scsi_put_command(cmd);
-               return BLKPREP_KILL;
-       }
-
-       return BLKPREP_OK;
 }
 
 static int scsi_prep_fn(struct request_queue *q, struct request *req)
 {
        struct scsi_device *sdev = q->queuedata;
-       int ret = BLKPREP_OK;
+       struct scsi_cmnd *cmd;
+       int specials_only = 0;
 
        /*
-        * If the device is not in running state we will reject some
-        * or all commands.
+        * Just check to see if the device is online.  If it isn't, we
+        * refuse to process any commands.  The device must be brought
+        * online before trying any recovery commands
         */
+       if (unlikely(!scsi_device_online(sdev))) {
+               sdev_printk(KERN_ERR, sdev,
+                           "rejecting I/O to offline device\n");
+               goto kill;
+       }
        if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
-               switch (sdev->sdev_state) {
-               case SDEV_OFFLINE:
-                       /*
-                        * If the device is offline we refuse to process any
-                        * commands.  The device must be brought online
-                        * before trying any recovery commands.
-                        */
-                       sdev_printk(KERN_ERR, sdev,
-                                   "rejecting I/O to offline device\n");
-                       ret = BLKPREP_KILL;
-                       break;
-               case SDEV_DEL:
-                       /*
-                        * If the device is fully deleted, we refuse to
-                        * process any commands as well.
-                        */
+               /* OK, we're not in a running state don't prep
+                * user commands */
+               if (sdev->sdev_state == SDEV_DEL) {
+                       /* Device is fully deleted, no commands
+                        * at all allowed down */
                        sdev_printk(KERN_ERR, sdev,
                                    "rejecting I/O to dead device\n");
-                       ret = BLKPREP_KILL;
-                       break;
-               case SDEV_QUIESCE:
-               case SDEV_BLOCK:
-                       /*
-                        * If the devices is blocked we defer normal commands.
-                        */
-                       if (!(req->cmd_flags & REQ_PREEMPT))
-                               ret = BLKPREP_DEFER;
-                       break;
-               default:
-                       /*
-                        * For any other not fully online state we only allow
-                        * special commands.  In particular any user initiated
-                        * command is not allowed.
-                        */
-                       if (!(req->cmd_flags & REQ_PREEMPT))
-                               ret = BLKPREP_KILL;
-                       break;
+                       goto kill;
                }
-
-               if (ret != BLKPREP_OK)
-                       goto out;
+               /* OK, we only allow special commands (i.e. not
+                * user initiated ones */
+               specials_only = sdev->sdev_state;
        }
 
-       switch (req->cmd_type) {
-       case REQ_TYPE_BLOCK_PC:
-               ret = scsi_setup_blk_pc_cmnd(sdev, req);
-               break;
-       case REQ_TYPE_FS:
-               ret = scsi_setup_fs_cmnd(sdev, req);
-               break;
-       default:
+       /*
+        * Find the actual device driver associated with this command.
+        * The SPECIAL requests are things like character device or
+        * ioctls, which did not originate from ll_rw_blk.  Note that
+        * the special field is also used to indicate the cmd for
+        * the remainder of a partially fulfilled request that can 
+        * come up when there is a medium error.  We have to treat
+        * these two cases differently.  We differentiate by looking
+        * at request->cmd, as this tells us the real story.
+        */
+       if (blk_special_request(req) && req->special)
+               cmd = req->special;
+       else if (blk_pc_request(req) || blk_fs_request(req)) {
+               if (unlikely(specials_only) && !(req->cmd_flags & REQ_PREEMPT)){
+                       if (specials_only == SDEV_QUIESCE ||
+                           specials_only == SDEV_BLOCK)
+                               goto defer;
+                       
+                       sdev_printk(KERN_ERR, sdev,
+                                   "rejecting I/O to device being removed\n");
+                       goto kill;
+               }
+                       
                /*
-                * All other command types are not supported.
-                *
-                * Note that these days the SCSI subsystem does not use
-                * REQ_TYPE_SPECIAL requests anymore.  These are only used
-                * (directly or via blk_insert_request) by non-SCSI drivers.
+                * Now try and find a command block that we can use.
                 */
+               if (!req->special) {
+                       cmd = scsi_get_command(sdev, GFP_ATOMIC);
+                       if (unlikely(!cmd))
+                               goto defer;
+               } else
+                       cmd = req->special;
+               
+               /* pull a tag out of the request if we have one */
+               cmd->tag = req->tag;
+       } else {
                blk_dump_rq_flags(req, "SCSI bad req");
-               ret = BLKPREP_KILL;
-               break;
+               goto kill;
        }
+       
+       /* note the overloading of req->special.  When the tag
+        * is active it always means cmd.  If the tag goes
+        * back for re-queueing, it may be reset */
+       req->special = cmd;
+       cmd->request = req;
+       
+       /*
+        * FIXME: drop the lock here because the functions below
+        * expect to be called without the queue lock held.  Also,
+        * previously, we dequeued the request before dropping the
+        * lock.  We hope REQ_STARTED prevents anything untoward from
+        * happening now.
+        */
+       if (blk_fs_request(req) || blk_pc_request(req)) {
+               int ret;
 
- out:
-       switch (ret) {
-       case BLKPREP_KILL:
-               req->errors = DID_NO_CONNECT << 16;
-               break;
-       case BLKPREP_DEFER:
                /*
-                * If we defer, the elv_next_request() returns NULL, but the
-                * queue must be restarted, so we plug here if no returning
-                * command will automatically do that.
+                * This will do a couple of things:
+                *  1) Fill in the actual SCSI command.
+                *  2) Fill in any other upper-level specific fields
+                * (timeout).
+                *
+                * If this returns 0, it means that the request failed
+                * (reading past end of disk, reading offline device,
+                * etc).   This won't actually talk to the device, but
+                * some kinds of consistency checking may cause the     
+                * request to be rejected immediately.
                 */
-               if (sdev->device_busy == 0)
-                       blk_plug_device(q);
-               break;
-       default:
-               req->cmd_flags |= REQ_DONTPREP;
+
+               /* 
+                * This sets up the scatter-gather table (allocating if
+                * required).
+                */
+               ret = scsi_init_io(cmd);
+               switch(ret) {
+                       /* For BLKPREP_KILL/DEFER the cmd was released */
+               case BLKPREP_KILL:
+                       goto kill;
+               case BLKPREP_DEFER:
+                       goto defer;
+               }
+               
+               /*
+                * Initialize the actual SCSI command for this request.
+                */
+               if (blk_pc_request(req)) {
+                       scsi_setup_blk_pc_cmnd(cmd);
+               } else if (req->rq_disk) {
+                       struct scsi_driver *drv;
+
+                       drv = *(struct scsi_driver 
**)req->rq_disk->private_data;
+                       if (unlikely(!drv->init_command(cmd))) {
+                               scsi_release_buffers(cmd);
+                               scsi_put_command(cmd);
+                               goto kill;
+                       }
+               }
        }
 
-       return ret;
+       /*
+        * The request is now prepped, no need to come back here
+        */
+       req->cmd_flags |= REQ_DONTPREP;
+       return BLKPREP_OK;
+
+ defer:
+       /* If we defer, the elv_next_request() returns NULL, but the
+        * queue must be restarted, so we plug here if no returning
+        * command will automatically do that. */
+       if (sdev->device_busy == 0)
+               blk_plug_device(q);
+       return BLKPREP_DEFER;
+ kill:
+       req->errors = DID_NO_CONNECT << 16;
+       return BLKPREP_KILL;
 }
 
 /*

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