Re: [PATCH v2 02/16] scsi: don't use fc_bsg_job::request and fc_bsg_job::reply directly

From: Johannes Thumshirn
Date: Thu Oct 13 2016 - 12:25:23 EST


On Thu, Oct 13, 2016 at 05:15:25PM +0200, Steffen Maier wrote:
> I'm puzzled.
>
> $ git bisect start fc_bsg master
> Bisecting: 8 revisions left to test after this (roughly 3 steps)
> [005d51510eee6102636d5dbb06310531c5d46151] scsi: fc: implement kref backed
> reference counting
> $ git bisect bad
> Bisecting: 3 revisions left to test after this (roughly 2 steps)
> [bef6da201de1bb81bb4d9511f9a155862efc251f] scsi: Unify interfaces of
> fc_bsg_jobdone and bsg_job_done
> $ git bisect bad
> Bisecting: 1 revision left to test after this (roughly 1 step)
> [3087864ce3d7282f59021245d8a5f83ef1caef18] scsi: don't use
> fc_bsg_job::request and fc_bsg_job::reply directly
> $ git bisect bad
> Bisecting: 0 revisions left to test after this (roughly 0 steps)
> [81aea44720d22d2e0c4a2613ae8b1c256ef6b0cb] scsi: Get rid of struct
> fc_bsg_buffer
> > $ git bisect good
> > 3087864ce3d7282f59021245d8a5f83ef1caef18 is the first bad commit
> > commit 3087864ce3d7282f59021245d8a5f83ef1caef18
> > Author: Johannes Thumshirn <jthumshirn@xxxxxxx>
> > Date: Wed Oct 12 15:06:28 2016 +0200
> >
> > scsi: don't use fc_bsg_job::request and fc_bsg_job::reply directly
> >
> > Don't use fc_bsg_job::request and fc_bsg_job::reply directly, but use
> > helper variables bsg_request and bsg_reply. This will be helpfull when
> > transitioning to bsg-lib.
> >
> > Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> >
> > :040000 040000 140c4b6829d5cfaec4079716e0795f63f8bc3bd2 0d9fe225615679550be91fbd9f84c09ab1e280fc M drivers
>
> From there (on the reverse bisect path) I get the following Oops,
> except for the full patch set having another stack trace as in my previous
> mail (dying in zfcp code).
>

[...]

>
> > @@ -3937,6 +3944,7 @@ fc_bsg_request_handler(struct request_queue *q, struct Scsi_Host *shost,
> > struct request *req;
> > struct fc_bsg_job *job;
> > enum fc_dispatch_result ret;
> > + struct fc_bsg_reply *bsg_reply;
> >
> > if (!get_device(dev))
> > return;
> > @@ -3973,8 +3981,9 @@ fc_bsg_request_handler(struct request_queue *q, struct Scsi_Host *shost,
> > /* check if we have the msgcode value at least */
> > if (job->request_len < sizeof(uint32_t)) {
> > BUG_ON(job->reply_len < sizeof(uint32_t));
> > - job->reply->reply_payload_rcv_len = 0;
> > - job->reply->result = -ENOMSG;
> > + bsg_reply = job->reply;
> > + bsg_reply->reply_payload_rcv_len = 0;
> > + bsg_reply->result = -ENOMSG;
> > job->reply_len = sizeof(uint32_t);
> > fc_bsg_jobdone(job);
> > spin_lock_irq(q->queue_lock);
> >

Ahm and what exactly can break here? It's just assigning variables. Now
I'm puzzled too.

I'll have to look into it tomorrow.

Byte,
Johannes

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