From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga06.intel.com ([134.134.136.31]:47760 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752148AbdKUNoH (ORCPT ); Tue, 21 Nov 2017 08:44:07 -0500 From: Adrian Hunter To: Ulf Hansson Cc: linux-mmc , linux-block , linux-kernel , Bough Chen , Alex Lemberg , Mateusz Nowak , Yuliy Izrailov , Jaehoon Chung , Dong Aisheng , Das Asutosh , Zhangfei Gao , Sahitya Tummala , Harjani Ritesh , Venu Byravarasu , Linus Walleij , Shawn Lin , Bartlomiej Zolnierkiewicz , Christoph Hellwig Subject: [PATCH V14 11/24] mmc: block: Add error-handling comments Date: Tue, 21 Nov 2017 15:42:37 +0200 Message-Id: <1511271770-3444-12-git-send-email-adrian.hunter@intel.com> In-Reply-To: <1511271770-3444-1-git-send-email-adrian.hunter@intel.com> References: <1511271770-3444-1-git-send-email-adrian.hunter@intel.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org Add error-handling comments to explain what would also be done for blk-mq if it used the legacy error-handling. Signed-off-by: Adrian Hunter --- drivers/mmc/core/block.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 607774fcb9f5..56624853d3d3 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -1966,7 +1966,11 @@ 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); @@ -1986,6 +1990,14 @@ 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) @@ -2002,11 +2014,20 @@ 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); @@ -2015,6 +2036,13 @@ 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; @@ -2026,6 +2054,10 @@ 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", @@ -2047,10 +2079,12 @@ 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); -- 1.9.1