2022-01-05 16:43:43

by Christian Loehle

[permalink] [raw]
Subject: [PATCH] mmc: block: fix read single on recovery logic

On reads with MMC_READ_MULTIPLE_BLOCK that fail,
the recovery handler will use MMC_READ_SINGLE_BLOCK for
each of the blocks, up to MMC_READ_SINGLE_RETRIES times each.
The logic for this is fixed to never report unsuccessful reads
as success to the block layer.

On command error with retries remaining, blk_update_request was
called with whatever value error was set last to.
In case it was last set to BLK_STS_OK (default), the read will be
reported as success, even though there was no data read from the device.
This could happen on a CRC mismatch for the response,
a card rejecting the command (e.g. again due to a CRC mismatch).
In case it was last set to BLK_STS_IOERR, the error is reported correctly,
but no retries will be attempted.

The patch now will count both command and data errors as retries and
send BLK_STS_IOERR if there are no retries remaining,
or BLK_STS_OK if the single read was successful in the meantime.

Signed-off-by: Christian Loehle <[email protected]>
---
drivers/mmc/core/block.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 90e1bcd03b46..d7d880ce0f8a 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1682,31 +1682,31 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
struct mmc_card *card = mq->card;
struct mmc_host *host = card->host;
blk_status_t error = BLK_STS_OK;
- int retries = 0;

do {
u32 status;
int err;
+ int retries = 0;

- mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
+ while (retries++ < MMC_READ_SINGLE_RETRIES) {
+ mmc_blk_rw_rq_prep(mqrq, card, 1, mq);

- mmc_wait_for_req(host, mrq);
+ mmc_wait_for_req(host, mrq);

- err = mmc_send_status(card, &status);
- if (err)
- goto error_exit;
-
- if (!mmc_host_is_spi(host) &&
- !mmc_ready_for_data(status)) {
- err = mmc_blk_fix_state(card, req);
+ err = mmc_send_status(card, &status);
if (err)
goto error_exit;
- }

- if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
- continue;
+ if (!mmc_host_is_spi(host) &&
+ !mmc_ready_for_data(status)) {
+ err = mmc_blk_fix_state(card, req);
+ if (err)
+ goto error_exit;
+ }

- retries = 0;
+ if (!mrq->cmd->error && !mrq->data->error)
+ break;
+ }

if (mrq->cmd->error ||
mrq->data->error ||
--
2.34.1
Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz
Managing Director: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782



2022-02-03 13:31:52

by Christian Loehle

[permalink] [raw]
Subject: Re: [PATCH] mmc: block: fix read single on recovery logic

So could anyone take a long at this so far?



From: Christian L?hle
Sent: Wednesday, January 5, 2022 5:43 PM
To: [email protected]; Christian L?hle; [email protected]; [email protected]
Cc: Avri Altman
Subject: [PATCH] mmc: block: fix read single on recovery logic
?
On reads with MMC_READ_MULTIPLE_BLOCK that fail,
the recovery handler will use MMC_READ_SINGLE_BLOCK for
each of the blocks, up to MMC_READ_SINGLE_RETRIES times each.
The logic for this is fixed to never report unsuccessful reads
as success to the block layer.

On command error with retries remaining, blk_update_request was
called with whatever value error was set last to.
In case it was last set to BLK_STS_OK (default), the read will be
reported as success, even though there was no data read from the device.
This could happen on a CRC mismatch for the response,
a card rejecting the command (e.g. again due to a CRC mismatch).
In case it was last set to BLK_STS_IOERR, the error is reported correctly,
but no retries will be attempted.

The patch now will count both command and data errors as retries and
send BLK_STS_IOERR if there are no retries remaining,
or BLK_STS_OK if the single read was successful in the meantime.

Signed-off-by: Christian Loehle <[email protected]>
---
?drivers/mmc/core/block.c | 28 ++++++++++++++--------------
?1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 90e1bcd03b46..d7d880ce0f8a 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1682,31 +1682,31 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
???????? struct mmc_card *card = mq->card;
???????? struct mmc_host *host = card->host;
???????? blk_status_t error = BLK_STS_OK;
-?????? int retries = 0;
?
???????? do {
???????????????? u32 status;
???????????????? int err;
+?????????????? int retries = 0;
?
-?????????????? mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
+?????????????? while (retries++ < MMC_READ_SINGLE_RETRIES) {
+?????????????????????? mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
?
-?????????????? mmc_wait_for_req(host, mrq);
+?????????????????????? mmc_wait_for_req(host, mrq);
?
-?????????????? err = mmc_send_status(card, &status);
-?????????????? if (err)
-?????????????????????? goto error_exit;
-
-?????????????? if (!mmc_host_is_spi(host) &&
-?????????????????? !mmc_ready_for_data(status)) {
-?????????????????????? err = mmc_blk_fix_state(card, req);
+?????????????????????? err = mmc_send_status(card, &status);
???????????????????????? if (err)
???????????????????????????????? goto error_exit;
-?????????????? }
?
-?????????????? if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
-?????????????????????? continue;
+?????????????????????? if (!mmc_host_is_spi(host) &&
+?????????????????????????? !mmc_ready_for_data(status)) {
+?????????????????????????????? err = mmc_blk_fix_state(card, req);
+?????????????????????????????? if (err)
+?????????????????????????????????????? goto error_exit;
+?????????????????????? }
?
-?????????????? retries = 0;
+?????????????????????? if (!mrq->cmd->error && !mrq->data->error)
+?????????????????????????????? break;
+?????????????? }
?
???????????????? if (mrq->cmd->error ||
???????????????????? mrq->data->error ||
--
2.34.1
=
Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz
Managing Director: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782

2022-02-04 15:41:49

by Ulf Hansson

[permalink] [raw]
Subject: Re: [PATCH] mmc: block: fix read single on recovery logic

+ Adrian

On Thu, 3 Feb 2022 at 11:09, Christian Löhle <[email protected]> wrote:
>
> So could anyone take a long at this so far?
>

Thanks for pinging. Apologize for the delay, it's on top of my "to-review" list.

I have added Adrian too, who knows this code very well too.

Kind regards
Uffe

>
>
> From: Christian Löhle
> Sent: Wednesday, January 5, 2022 5:43 PM
> To: [email protected]; Christian Löhle; [email protected]; [email protected]
> Cc: Avri Altman
> Subject: [PATCH] mmc: block: fix read single on recovery logic
>
> On reads with MMC_READ_MULTIPLE_BLOCK that fail,
> the recovery handler will use MMC_READ_SINGLE_BLOCK for
> each of the blocks, up to MMC_READ_SINGLE_RETRIES times each.
> The logic for this is fixed to never report unsuccessful reads
> as success to the block layer.
>
> On command error with retries remaining, blk_update_request was
> called with whatever value error was set last to.
> In case it was last set to BLK_STS_OK (default), the read will be
> reported as success, even though there was no data read from the device.
> This could happen on a CRC mismatch for the response,
> a card rejecting the command (e.g. again due to a CRC mismatch).
> In case it was last set to BLK_STS_IOERR, the error is reported correctly,
> but no retries will be attempted.
>
> The patch now will count both command and data errors as retries and
> send BLK_STS_IOERR if there are no retries remaining,
> or BLK_STS_OK if the single read was successful in the meantime.
>
> Signed-off-by: Christian Loehle <[email protected]>
> ---
> drivers/mmc/core/block.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index 90e1bcd03b46..d7d880ce0f8a 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -1682,31 +1682,31 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
> struct mmc_card *card = mq->card;
> struct mmc_host *host = card->host;
> blk_status_t error = BLK_STS_OK;
> - int retries = 0;
>
> do {
> u32 status;
> int err;
> + int retries = 0;
>
> - mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
> + while (retries++ < MMC_READ_SINGLE_RETRIES) {
> + mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
>
> - mmc_wait_for_req(host, mrq);
> + mmc_wait_for_req(host, mrq);
>
> - err = mmc_send_status(card, &status);
> - if (err)
> - goto error_exit;
> -
> - if (!mmc_host_is_spi(host) &&
> - !mmc_ready_for_data(status)) {
> - err = mmc_blk_fix_state(card, req);
> + err = mmc_send_status(card, &status);
> if (err)
> goto error_exit;
> - }
>
> - if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
> - continue;
> + if (!mmc_host_is_spi(host) &&
> + !mmc_ready_for_data(status)) {
> + err = mmc_blk_fix_state(card, req);
> + if (err)
> + goto error_exit;
> + }
>
> - retries = 0;
> + if (!mrq->cmd->error && !mrq->data->error)
> + break;
> + }
>
> if (mrq->cmd->error ||
> mrq->data->error ||
> --
> 2.34.1
> =
> Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz
> Managing Director: Dr. Jan Peter Berns.
> Commercial register of local courts: Freiburg HRB381782
>

2022-02-04 20:09:27

by Adrian Hunter

[permalink] [raw]
Subject: Re: [PATCH] mmc: block: fix read single on recovery logic

On 04/02/2022 11:47, Ulf Hansson wrote:
> + Adrian
>
> On Thu, 3 Feb 2022 at 11:09, Christian Löhle <[email protected]> wrote:
>>
>> So could anyone take a long at this so far?
>>
>
> Thanks for pinging. Apologize for the delay, it's on top of my "to-review" list.
>
> I have added Adrian too, who knows this code very well too.
>
> Kind regards
> Uffe
>
>>
>>
>> From: Christian Löhle
>> Sent: Wednesday, January 5, 2022 5:43 PM
>> To: [email protected]; Christian Löhle; [email protected]; [email protected]
>> Cc: Avri Altman
>> Subject: [PATCH] mmc: block: fix read single on recovery logic
>>
>> On reads with MMC_READ_MULTIPLE_BLOCK that fail,
>> the recovery handler will use MMC_READ_SINGLE_BLOCK for
>> each of the blocks, up to MMC_READ_SINGLE_RETRIES times each.
>> The logic for this is fixed to never report unsuccessful reads
>> as success to the block layer.
>>
>> On command error with retries remaining, blk_update_request was
>> called with whatever value error was set last to.
>> In case it was last set to BLK_STS_OK (default), the read will be
>> reported as success, even though there was no data read from the device.
>> This could happen on a CRC mismatch for the response,
>> a card rejecting the command (e.g. again due to a CRC mismatch).
>> In case it was last set to BLK_STS_IOERR, the error is reported correctly,
>> but no retries will be attempted.
>>
>> The patch now will count both command and data errors as retries and
>> send BLK_STS_IOERR if there are no retries remaining,
>> or BLK_STS_OK if the single read was successful in the meantime.
>>
>> Signed-off-by: Christian Loehle <[email protected]>

Thanks for the patch.

Looks OK, although a couple of comments below, plus it needs
a Fixes tag, and Cc for stable.

Fixes: 81196976ed946c ("mmc: block: Add blk-mq support")
Cc: [email protected]

>> ---
>> drivers/mmc/core/block.c | 28 ++++++++++++++--------------
>> 1 file changed, 14 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
>> index 90e1bcd03b46..d7d880ce0f8a 100644
>> --- a/drivers/mmc/core/block.c
>> +++ b/drivers/mmc/core/block.c
>> @@ -1682,31 +1682,31 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
>> struct mmc_card *card = mq->card;
>> struct mmc_host *host = card->host;
>> blk_status_t error = BLK_STS_OK;
>> - int retries = 0;
>>
>> do {
>> u32 status;
>> int err;
>> + int retries = 0;
>>
>> - mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
>> + while (retries++ < MMC_READ_SINGLE_RETRIES) {

Because this is now checked at the top of the loop, wouldn't that
result in one fewer retries than before? So, maybe:

while (retries++ <= MMC_READ_SINGLE_RETRIES) {

>> + mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
>>
>> - mmc_wait_for_req(host, mrq);
>> + mmc_wait_for_req(host, mrq);
>>
>> - err = mmc_send_status(card, &status);
>> - if (err)
>> - goto error_exit;
>> -
>> - if (!mmc_host_is_spi(host) &&
>> - !mmc_ready_for_data(status)) {
>> - err = mmc_blk_fix_state(card, req);
>> + err = mmc_send_status(card, &status);
>> if (err)
>> goto error_exit;
>> - }
>>
>> - if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
>> - continue;
>> + if (!mmc_host_is_spi(host) &&
>> + !mmc_ready_for_data(status)) {
>> + err = mmc_blk_fix_state(card, req);
>> + if (err)
>> + goto error_exit;
>> + }
>>
>> - retries = 0;
>> + if (!mrq->cmd->error && !mrq->data->error)

We weren't retrying for data errors before, and I don't think we want to
because single block read can be very slow. i.e. just

if (!mrq->cmd->error)

>> + break;
>> + }
>>
>> if (mrq->cmd->error ||
>> mrq->data->error ||
>> --
>> 2.34.1
>> =
>> Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz
>> Managing Director: Dr. Jan Peter Berns.
>> Commercial register of local courts: Freiburg HRB381782
>>