[PATCHv4 1/2] mmc: block: Remove error check of hw_reset on reset

Christian Löhle
2022-10-12T18:38:10Z

Before switching back to the right partition in mmc_blk_reset there used
to be a check if hw_reset was even supported. This return value
was removed, so there is no reason to check. Furthermore ensure
part_curr is not falsely set to a valid value on reset or
partition switch error.

As part of this change the code paths of mmc_blk_reset calls were checked
to ensure no commands are issued after a failed mmc_blk_reset directly
without going through the block layer.

Fixes: fefdd3c91e0a ("mmc: core: Drop superfluous validations in mmc_hw|sw_reset()")
Cc: stable@vger.kernel.org

Signed-off-by: Christian Loehle <cloehle@hyperstone.com>
---
-v4: Only partition switch if necessary and fix one mmc_blk_reset call
-v3: Ensure invalid part_curr on error
-v2: Do not attempt to switch partitions if reset failed

drivers/mmc/core/block.c | 42 ++++++++++++++++++++++++----------------
1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index ce89611a136e..2619cc47b97c 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -134,6 +134,7 @@ struct mmc_blk_data {
* track of the current selected device partition.
*/
unsigned int part_curr;
+#define MMC_BLK_PART_INVALID UINT_MAX /* Unknown partition active */
int area_type;

/* debugfs files (only in main mmc_blk_data) */
@@ -987,33 +988,39 @@ static unsigned int mmc_blk_data_timeout_ms(struct mmc_host *host,
return ms;
}

+/*
+ * Attempts to reset the card and get back to the requested partition.
+ * Therefore any error here must result in cancelling the block layer
+ * request, it must not be reattempted without going through the mmc_blk
+ * partition sanity checks.
+ */
static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
int type)
{
int err;
+ struct mmc_blk_data *main_md = dev_get_drvdata(&host->card->dev);

if (md->reset_done & type)
return -EEXIST;

md->reset_done |= type;
err = mmc_hw_reset(host->card);
+ /*
+ * A successful reset will leave the card in the main partition, but
+ * upon failure it might not be, so set it to MMC_BLK_PART_INVALID
+ * in that case.
+ */
+ main_md->part_curr = err ? MMC_BLK_PART_INVALID : main_md->part_type;
+ if (err)
+ return err;
/* Ensure we switch back to the correct partition */
- if (err) {
- struct mmc_blk_data *main_md =
- dev_get_drvdata(&host->card->dev);
- int part_err;
-
- main_md->part_curr = main_md->part_type;
- part_err = mmc_blk_part_switch(host->card, md->part_type);
- if (part_err) {
- /*
- * We have failed to get back into the correct
- * partition, so we need to abort the whole request.
- */
- return -ENODEV;
- }
- }
- return err;
+ if (mmc_blk_part_switch(host->card, md->part_type))
+ /*
+ * We have failed to get back into the correct
+ * partition, so we need to abort the whole request.
+ */
+ return -ENODEV;
+ return 0;
}

static inline void mmc_blk_reset_success(struct mmc_blk_data *md, int type)
@@ -1868,7 +1875,8 @@ static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)

/* Reset before last retry */
if (mqrq->retries + 1 == MMC_MAX_RETRIES)
- mmc_blk_reset(md, card->host, type);
+ if (mmc_blk_reset(md, card->host, type))
+ return;

/* Command errors fail fast, so use all MMC_MAX_RETRIES */
if (brq->sbc.error || brq->cmd.error)
--
2.37.3

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