On Sat, Oct 27 2007, Sebastian Siewior wrote:
> * Jens Axboe | 2007-10-26 13:42:30 [+0200]:
>
> >> [2] http://download.breakpoint.cc/bug/bug_rc1_patch_reboot.jpeg 171 KiB
> >
> >Ah, second BUG() for same issue. Try this one. This?
> >
> >diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> >index 61fdaf0..57fde7b 100644
> >--- a/drivers/scsi/scsi_lib.c
> >+++ b/drivers/scsi/scsi_lib.c
> >@@ -1115,6 +1115,8 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
> > * kmapping pages)
> > */
> > cmd->use_sg = req->nr_phys_segments;
> >+ if (!cmd->use_sg)
> >+ return 0;
> >
> > /*
> > * If sg table allocation fails, requeue request later.
> >@@ -1191,7 +1193,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev,
> >struct request *req)
> > if (req->bio) {
> > int ret;
> >
> >- BUG_ON(!req->nr_phys_segments);
> >+ BUG_ON(!req->nr_phys_segments && req->bio->bi_size);
> >
> > ret = scsi_init_io(cmd);
> > if (unlikely(ret))
> >@@ -1236,9 +1238,10 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev,
> >struct request *req)
> > if (ret != BLKPREP_OK)
> > return ret;
> > /*
> >- * Filesystem requests must transfer data.
> >+ * Filesystem requests must transfer data, unless it's an empty
> >+ * barrier.
> > */
> >- BUG_ON(!req->nr_phys_segments);
> >+ BUG_ON(!req->nr_phys_segments && !bio_empty_barrier(req->bio));
> >
> > cmd = scsi_get_cmd_from_req(sdev, req);
> > if (unlikely(!cmd))
> >
>
> I'm afraid you did not make it to the next level. I hope you have
> another man :). [1] shows the result. I double checked it, it seems to
> be the same bug() with the second patch.
>
> [1] http://download.breakpoint.cc/bug/bug_patch2.jpeg 134 KiB
OK, can you see what this produces?
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 61fdaf0..4042269 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1115,6 +1115,8 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
* kmapping pages)
*/
cmd->use_sg = req->nr_phys_segments;
+ if (!cmd->use_sg)
+ return 0;
/*
* If sg table allocation fails, requeue request later.
@@ -1191,7 +1193,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev,
struct request *req)
if (req->bio) {
int ret;
- BUG_ON(!req->nr_phys_segments);
+ BUG_ON(!req->nr_phys_segments && req->bio->bi_size);
ret = scsi_init_io(cmd);
if (unlikely(ret))
@@ -1236,9 +1238,11 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct
request *req)
if (ret != BLKPREP_OK)
return ret;
/*
- * Filesystem requests must transfer data.
+ * Filesystem requests must transfer data, unless it's an empty
+ * barrier.
*/
- BUG_ON(!req->nr_phys_segments);
+ if (!req->nr_phys_segments && !bio_empty_barrier(req->bio))
+ blk_dump_rq_flags(req, "scsi");
cmd = scsi_get_cmd_from_req(sdev, req);
if (unlikely(!cmd))
--
Jens Axboe
-
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