[PATCH 0/1] mmc: core: Further fix thread wake-up

[PATCH 0/1] mmc: core: Further fix thread wake-up

[Adrian Hunter]

Hi

Here is the fix for the hang that Ritesh was seeing while testing
the Software Command Queue patches.


Adrian Hunter (1):
      mmc: core: Further fix thread wake-up

 drivers/mmc/core/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)


Regards
Adrian

[PATCH 1/1] mmc: core: Further fix thread wake-up

[Adrian Hunter]

Commit e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up") did not go far
enough. mmc_wait_for_data_req_done() still contains some problems and can
be further simplified.  First it should not touch
context_info->is_waiting_last_req because that is a wake-up control used by
the owner of the context. Secondly, it should always return when one of its
wake-up conditions is met because, again, that is contolled by the owner of
the context.

While the current block driver does not have an issue, these problems were
exposed during testing of the Software Command Queue patches.

Fixes: e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 543eadd230e5..1076b9d89df3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -496,8 +496,7 @@ static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
  * Returns enum mmc_blk_status after checking errors.
  */
 static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
-				      struct mmc_request *mrq,
-				      struct mmc_async_req *next_req)
+						      struct mmc_request *mrq)
 {
 	struct mmc_command *cmd;
 	struct mmc_context_info *context_info = &host->context_info;
@@ -507,7 +506,7 @@ static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
 		wait_event_interruptible(context_info->wait,
 				(context_info->is_done_rcv ||
 				 context_info->is_new_req));
-		context_info->is_waiting_last_req = false;
+
 		if (context_info->is_done_rcv) {
 			context_info->is_done_rcv = false;
 			cmd = mrq->cmd;
@@ -527,10 +526,9 @@ static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
 				__mmc_start_request(host, mrq);
 				continue; /* wait for done/new event again */
 			}
-		} else if (context_info->is_new_req) {
-			if (!next_req)
-				return MMC_BLK_NEW_REQUEST;
 		}
+
+		return MMC_BLK_NEW_REQUEST;
 	}
 	mmc_retune_release(host);
 	return status;
@@ -660,7 +658,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
 		mmc_pre_req(host, areq->mrq);
 
 	if (host->areq) {
-		status = mmc_wait_for_data_req_done(host, host->areq->mrq, areq);
+		status = mmc_wait_for_data_req_done(host, host->areq->mrq);
 		if (status == MMC_BLK_NEW_REQUEST) {
 			if (ret_stat)
 				*ret_stat = status;
-- 
1.9.1

Re: [PATCH 1/1] mmc: core: Further fix thread wake-up

[Ritesh Harjani]

On 12/19/2016 7:27 PM, Adrian Hunter wrote:
> Commit e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up") did not go far
> enough. mmc_wait_for_data_req_done() still contains some problems and can
> be further simplified.  First it should not touch
> context_info->is_waiting_last_req because that is a wake-up control used by
> the owner of the context. Secondly, it should always return when one of its
> wake-up conditions is met because, again, that is contolled by the owner of
> the context.
>
> While the current block driver does not have an issue, these problems were
> exposed during testing of the Software Command Queue patches.
>
> Fixes: e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up")
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Patch looks good to me. Please feel free to add.

Tested-by: Harjani Ritesh <riteshh@codeaurora.org>

Regards
Ritesh

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH 1/1] mmc: core: Further fix thread wake-up

[Ulf Hansson]

On 19 December 2016 at 14:57, Adrian Hunter <adrian.hunter@intel.com> wrote:
> Commit e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up") did not go far
> enough. mmc_wait_for_data_req_done() still contains some problems and can
> be further simplified.  First it should not touch
> context_info->is_waiting_last_req because that is a wake-up control used by
> the owner of the context. Secondly, it should always return when one of its
> wake-up conditions is met because, again, that is contolled by the owner of
> the context.
>
> While the current block driver does not have an issue, these problems were
> exposed during testing of the Software Command Queue patches.
>
> Fixes: e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up")
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Thanks, applied for fixes!

Kind regards
Uffe

> ---
>  drivers/mmc/core/core.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 543eadd230e5..1076b9d89df3 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -496,8 +496,7 @@ static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
>   * Returns enum mmc_blk_status after checking errors.
>   */
>  static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
> -                                     struct mmc_request *mrq,
> -                                     struct mmc_async_req *next_req)
> +                                                     struct mmc_request *mrq)
>  {
>         struct mmc_command *cmd;
>         struct mmc_context_info *context_info = &host->context_info;
> @@ -507,7 +506,7 @@ static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
>                 wait_event_interruptible(context_info->wait,
>                                 (context_info->is_done_rcv ||
>                                  context_info->is_new_req));
> -               context_info->is_waiting_last_req = false;
> +
>                 if (context_info->is_done_rcv) {
>                         context_info->is_done_rcv = false;
>                         cmd = mrq->cmd;
> @@ -527,10 +526,9 @@ static enum mmc_blk_status mmc_wait_for_data_req_done(struct mmc_host *host,
>                                 __mmc_start_request(host, mrq);
>                                 continue; /* wait for done/new event again */
>                         }
> -               } else if (context_info->is_new_req) {
> -                       if (!next_req)
> -                               return MMC_BLK_NEW_REQUEST;
>                 }
> +
> +               return MMC_BLK_NEW_REQUEST;
>         }
>         mmc_retune_release(host);
>         return status;
> @@ -660,7 +658,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
>                 mmc_pre_req(host, areq->mrq);
>
>         if (host->areq) {
> -               status = mmc_wait_for_data_req_done(host, host->areq->mrq, areq);
> +               status = mmc_wait_for_data_req_done(host, host->areq->mrq);
>                 if (status == MMC_BLK_NEW_REQUEST) {
>                         if (ret_stat)
>                                 *ret_stat = status;
> --
> 1.9.1
>

Re: [PATCH 1/1] mmc: core: Further fix thread wake-up

[Bartlomiej Zolnierkiewicz]

Hi,

On Tuesday, December 20, 2016 11:56:23 AM Ulf Hansson wrote:
> On 19 December 2016 at 14:57, Adrian Hunter <adrian.hunter@intel.com> wrote:
> > Commit e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up") did not go far
> > enough. mmc_wait_for_data_req_done() still contains some problems and can
> > be further simplified.  First it should not touch
> > context_info->is_waiting_last_req because that is a wake-up control used by
> > the owner of the context. Secondly, it should always return when one of its
> > wake-up conditions is met because, again, that is contolled by the owner of
> > the context.
> >
> > While the current block driver does not have an issue, these problems were
> > exposed during testing of the Software Command Queue patches.

This sentence no longer seems to be true..

> > Fixes: e0097cf5f2f1 ("mmc: queue: Fix queue thread wake-up")
> > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> 
> Thanks, applied for fixes!

Seems that I'm late but FWIW for the patch content:

Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics