On Tue, 2016-10-25 at 15:16 -0700, Bart Van Assche wrote:
> On 10/23/2016 08:20 PM, Gabriel Krisman Bertazi wrote:
> > +
> > /**
> > * scsi_execute - insert request and wait for the result
> > * @sdev: scsi device
> > @@ -187,7 +197,14 @@ int scsi_execute(struct scsi_device *sdev,
> > const unsigned char *cmd,
> > struct request *req;
> > int write = (data_direction == DMA_TO_DEVICE);
> > int ret = DRIVER_ERROR << 24;
> > + unsigned char sense_buf[SCSI_SENSE_BUFFERSIZE];
> >
> > + if (!sense) {
> > + sense = sense_buf;
> > + memset(sense, 0, SCSI_SENSE_BUFFERSIZE);
> > + }
> > +
> > + retry:
> > req = blk_get_request(sdev->request_queue, write,
> > __GFP_RECLAIM);
> > if (IS_ERR(req))
> > return ret;
> > @@ -210,6 +227,13 @@ int scsi_execute(struct scsi_device *sdev,
> > const unsigned char *cmd,
> > */
> > blk_execute_rq(req->q, NULL, req, 1);
> >
> > + if (scsi_sense_unit_attention(sense) && req->retries > 0)
> > {
> > + memset(sense, 0, SCSI_SENSE_BUFFERSIZE);
> > + retries = req->retries - 1;
> > + blk_put_request(req);
> > + goto retry;
> > + }
> > +
> > /*
> > * Some devices (USB mass-storage in particular) may
> > transfer
> > * garbage data together with a residue indicating that
> > the data
>
> From scsi_io_completion():
>
> if (sense_valid && !sense_deferred) {
> switch (sshdr.sense_key) {
> case UNIT_ATTENTION:
> if (cmd->device->removable) {
> cmd->device->changed = 1;
> action = ACTION_FAIL;
> } else {
> action = ACTION_RETRY;
> }
> [ ... ]
>
> Why do you think new retry code is needed in scsi_execute()?
Because scsi_execute uses REQ_BLOCK_PC which is completed before you
get to that code.
James
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