On Tue, May 12, 2020 at 11:03:18AM +0200, Javier González wrote:
> On 11.05.2020 16:50, Dan Carpenter wrote:
> > Hello Javier González,
> >
> > The patch b6730dd4a954: "lightnvm: pblk: return NVM_ error on failed
> > submission" from Jun 1, 2018, leads to the following static checker
> > warning:
> >
> > drivers/lightnvm/pblk-recovery.c:473 pblk_recov_scan_oob()
> > warn: 'pblk->inflight_io.counter' not decremented on lines: 426.
> >
> > drivers/lightnvm/pblk-recovery.c
> > 417
> > 418 for (j = 0; j < pblk->min_write_pgs; j++, i++)
> > 419 ppa_list[i] =
> > 420 addr_to_gen_ppa(pblk, paddr + j, line->id);
> > 421 }
> > 422
> > 423 ret = pblk_submit_io_sync(pblk, rqd, data);
> > 424 if (ret) {
> > 425 pblk_err(pblk, "I/O submission failed: %d\n", ret);
> > 426 return ret;
> >
> > The pblk_submit_io_sync() increments the pblk->inflight_io counter but
> > doesn't decrement it on all error paths. It looks like something a
> > little bit subtle is going no but I'm not sure how it works exactly.
> >
> > 427 }
> > 428
> > 429 atomic_dec(&pblk->inflight_io);
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > 430
> > 431 /* If a read fails, do a best effort by padding the line and retrying */
> > 432 if (rqd->error && rqd->error != NVM_RSP_WARN_HIGHECC) {
> > 433 int pad_distance, ret;
> > 434
> > 435 if (padded) {
> > 436 pblk_log_read_err(pblk, rqd);
> > 437 return -EINTR;
> > 438 }
> > 439
> >
> > regards,
> > dan carpenter
>
> Hi Dan,
>
> As I recall, we used this counter to see the total I/Os that were
> submitted through pblk and wanted to keep track of how many of them
> completed - so the error path did not decrement as it was I/O that had
> made it to the FTL but had not reached the device.
>
> I can see how this is confusing, as through time we introduced dedicated
> counters to the failed I/Os and inflight became a counter on I/Os going
> to the device.
>
> I believe we can fix this by checking the return value on the submit
> functions and decrementing in case of error.
>
> Do you want me to send a patch or you want to fix it yourself?
Could you send the patch?
regards,
dan carpenter
