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?
Thanks,
Javier
