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Commit 6d3898a6 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

mmc: block: Add error-handling comments 



Add error-handling comments to explain what would also be done for blk-mq
if it used the legacy error-handling.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent afab1bb8

drivers/mmc/core/block.c

+35 −1
Original line number Diff line number Diff line
@@ -1911,7 +1911,11 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
		case MMC_BLK_SUCCESS:

		case MMC_BLK_PARTIAL:

			/*

			 * A block was successfully transferred.

			 * Reset success, and accept bytes_xfered. For

			 * MMC_BLK_PARTIAL re-submit the remaining request. For

			 * MMC_BLK_SUCCESS error out the remaining request (it

			 * could not be re-submitted anyway if a next request

			 * had already begun).

			 */

			mmc_blk_reset_success(md, type);
@@ -1931,6 +1935,14 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			}

			break;

		case MMC_BLK_CMD_ERR:

			/*

			 * For SD cards, get bytes written, but do not accept

			 * bytes_xfered if that fails. For MMC cards accept

			 * bytes_xfered. Then try to reset. If reset fails then

			 * error out the remaining request, otherwise retry

			 * once (N.B mmc_blk_reset() will not succeed twice in a

			 * row).

			 */

			req_pending = mmc_blk_rw_cmd_err(md, card, brq, old_req, req_pending);

			if (mmc_blk_reset(md, card->host, type)) {

				if (req_pending)
@@ -1947,11 +1959,20 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			}

			break;

		case MMC_BLK_RETRY:

			/*

			 * Do not accept bytes_xfered, but retry up to 5 times,

			 * otherwise same as abort.

			 */

			retune_retry_done = brq->retune_retry_done;

			if (retry++ < 5)

				break;

			/* Fall through */

		case MMC_BLK_ABORT:

			/*

			 * Do not accept bytes_xfered, but try to reset. If

			 * reset succeeds, try once more, otherwise error out

			 * the request.

			 */

			if (!mmc_blk_reset(md, card->host, type))

				break;

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);
@@ -1960,6 +1981,13 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
		case MMC_BLK_DATA_ERR: {

			int err;



			/*

			 * Do not accept bytes_xfered, but try to reset. If

			 * reset succeeds, try once more. If reset fails with

			 * ENODEV which means the partition is wrong, then error

			 * out the request. Otherwise attempt to read one sector

			 * at a time.

			 */

			err = mmc_blk_reset(md, card->host, type);

			if (!err)

				break;
@@ -1971,6 +1999,10 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			/* Fall through */

		}

		case MMC_BLK_ECC_ERR:

			/*

			 * Do not accept bytes_xfered. If reading more than one

			 * sector, try reading one sector at a time.

			 */

			if (brq->data.blocks > 1) {

				/* Redo read one sector at a time */

				pr_warn("%s: retrying using single block read\n",
@@ -1992,10 +2024,12 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			}

			break;

		case MMC_BLK_NOMEDIUM:

			/* Do not accept bytes_xfered. Error out the request */

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

			mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

			return;

		default:

			/* Do not accept bytes_xfered. Error out the request */

			pr_err("%s: Unhandled return value (%d)",

					old_req->rq_disk->disk_name, status);

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);