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Commit 6a79e391 authored by Adrian Hunter's avatar Adrian Hunter Committed by Pierre Ossman
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mmc_block: ensure all sectors that do not have errors are read 



If a card encounters an ECC error while reading a sector it will
timeout.  Instead of reporting the entire I/O request as having
an error, redo the I/O one sector at a time so that all readable
sectors are provided to the upper layers.

Signed-off-by: default avatarAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
parent a0d045ca

drivers/mmc/card/block.c

+59 −17
Original line number Diff line number Diff line
@@ -229,7 +229,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
	struct mmc_blk_data *md = mq->data;

	struct mmc_card *card = md->queue.card;

	struct mmc_blk_request brq;

	int ret = 1;

	int ret = 1, disable_multi = 0;



	mmc_claim_host(card->host);
@@ -251,6 +251,14 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		brq.stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;

		brq.data.blocks = req->nr_sectors;



		/*

		 * After a read error, we redo the request one sector at a time

		 * in order to accurately determine which sectors can be read

		 * successfully.

		 */

		if (disable_multi && brq.data.blocks > 1)

			brq.data.blocks = 1;



		if (brq.data.blocks > 1) {

			/* SPI multiblock writes terminate using a special

			 * token, not a STOP_TRANSMISSION request.
@@ -279,6 +287,25 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		brq.data.sg = mq->sg;

		brq.data.sg_len = mmc_queue_map_sg(mq);



		/*

		 * Adjust the sg list so it is the same size as the

		 * request.

		 */

		if (brq.data.blocks != req->nr_sectors) {

			int i, data_size = brq.data.blocks << 9;

			struct scatterlist *sg;



			for_each_sg(brq.data.sg, sg, brq.data.sg_len, i) {

				data_size -= sg->length;

				if (data_size <= 0) {

					sg->length += data_size;

					i++;

					break;

				}

			}

			brq.data.sg_len = i;

		}



		mmc_queue_bounce_pre(mq);



		mmc_wait_for_req(card->host, &brq.mrq);
@@ -290,8 +317,16 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		 * until later as we need to wait for the card to leave

		 * programming mode even when things go wrong.

		 */

		if (brq.cmd.error || brq.data.error || brq.stop.error)

		if (brq.cmd.error || brq.data.error || brq.stop.error) {

			if (brq.data.blocks > 1 && rq_data_dir(req) == READ) {

				/* Redo read one sector at a time */

				printk(KERN_WARNING "%s: retrying using single "

				       "block read\n", req->rq_disk->disk_name);

				disable_multi = 1;

				continue;

			}

			status = get_card_status(card, req);

		}



		if (brq.cmd.error) {

			printk(KERN_ERR "%s: error %d sending read/write "
@@ -348,8 +383,20 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
#endif

		}



		if (brq.cmd.error || brq.data.error || brq.stop.error)

		if (brq.cmd.error || brq.stop.error || brq.data.error) {

			if (rq_data_dir(req) == READ) {

				/*

				 * After an error, we redo I/O one sector at a

				 * time, so we only reach here after trying to

				 * read a single sector.

				 */

				spin_lock_irq(&md->lock);

				ret = __blk_end_request(req, -EIO, brq.data.blksz);

				spin_unlock_irq(&md->lock);

				continue;

			}

			goto cmd_err;

		}



		/*

		 * A block was successfully transferred.
@@ -371,11 +418,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
	 * If the card is not SD, we can still ok written sectors

	 * as reported by the controller (which might be less than

	 * the real number of written sectors, but never more).

	 *

	 * For reads we just fail the entire chunk as that should

	 * be safe in all cases.

	 */

	if (rq_data_dir(req) != READ) {

	if (mmc_card_sd(card)) {

		u32 blocks;
@@ -390,7 +433,6 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		ret = __blk_end_request(req, 0, brq.data.bytes_xfered);

		spin_unlock_irq(&md->lock);

	}

	}



	mmc_release_host(card->host);