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From fba35a4bb8f9cabcd374e19a2a34ee5496d971d2 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <ext-adrian.hunter@nokia.com>
Date: Wed, 31 Dec 2008 18:21:17 +0100
Subject: [PATCH 23/23] 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: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
---
drivers/mmc/card/block.c | 76 +++++++++++++++++++++++++++++++++++----------
1 files changed, 59 insertions(+), 17 deletions(-)
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index cc9b3ab..45b1f43 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -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.
@@ -371,25 +418,20 @@ 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;
+ if (mmc_card_sd(card)) {
+ u32 blocks;
- blocks = mmc_sd_num_wr_blocks(card);
- if (blocks != (u32)-1) {
- spin_lock_irq(&md->lock);
- ret = __blk_end_request(req, 0, blocks << 9);
- spin_unlock_irq(&md->lock);
- }
- } else {
+ blocks = mmc_sd_num_wr_blocks(card);
+ if (blocks != (u32)-1) {
spin_lock_irq(&md->lock);
- ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
+ ret = __blk_end_request(req, 0, blocks << 9);
spin_unlock_irq(&md->lock);
}
+ } else {
+ spin_lock_irq(&md->lock);
+ ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
+ spin_unlock_irq(&md->lock);
}
mmc_release_host(card->host);
--
1.5.6.5
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