On Thursday, February 09, 2017 04:33:58 PM Linus Walleij wrote:

Instead of doing retries at the same time as trying to submit new
requests, do the retries when the request is reported as completed
by the driver, in the finalization worker.

This is achieved by letting the core worker call back into the block
layer using mmc_blk_rw_done(), that will read the status and repeatedly
try to hammer the request using single request etc by calling back to
the core layer using mmc_restart_areq()

The beauty of it is that the completion will not complete until the
block layer has had the opportunity to hammer a bit at the card using
a bunch of different approaches in the while() loop in
mmc_blk_rw_done()

The algorithm for recapture, retry and handle errors is essentially
identical to the one we used to have in mmc_blk_issue_rw_rq(),
only augmented to get called in another path.

We have to add and initialize a pointer back to the struct mmc_queue
from the struct mmc_queue_req to find the queue from the asynchronous
request.

Signed-off-by: Linus Walleij <redacted>

It seems that after this change we can end up queuing more
work for kthread from the kthread worker itself and wait
inside it for this nested work to complete.  I hope that
you've tested it with simulating errors and it all works.

Under this assumption:

Reviewed-by: Bartlomiej Zolnierkiewicz <redacted>

Also some very minor nit:

+       case MMC_BLK_DATA_ERR: {
+               int err;
+                       err = mmc_blk_reset(md, host, type);

During the code movement CodingStyle suffered.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics