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Commit a1ccf2b5 authored by Sarthak Garg's avatar Sarthak Garg Committed by Gerrit - the friendly Code Review server
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mmc: core: Retry claim host in mmc_sd_detect 



Use mmc_try_claim_host with a timeout instead of mmc_claim_host in
mmc_sd_detect. This is to ensure that mmc rescan work item is doesn't
get blocked on claim_host for longer period.
In the pm_suspend path, we cancel the mmc_rescan work item.
If this work item is already scheduled, suspend would be blocked till
mmc_rescan gets finished. In case, mmc_rescan is blocked on claim_host
lock, pm_suspend could get blocked for longer period.  This can result
in momentary UI freeze since pm_suspend is blocked for longer duration.
This change is to prevent this scenario.

Change-Id: Ib93bae6745a153bad3579ae42f46c3c3a7c1b95a
Signed-off-by: default avatarVeerabhadrarao Badiganti <vbadigan@codeaurora.org>
Signed-off-by: default avatarSarthak Garg <sartgarg@codeaurora.org>
parent 3717aafa

drivers/mmc/core/core.c

+41 −0
Original line number Diff line number Diff line
@@ -1644,6 +1644,47 @@ int __mmc_claim_host(struct mmc_host *host, struct mmc_ctx *ctx, 
}

EXPORT_SYMBOL(__mmc_claim_host);



#if defined(CONFIG_SDC_QTI)

/**

 *   mmc_try_claim_host - try exclusively to claim a host

 *   and keep trying for given time, with a gap of 10ms

 *   @host: mmc host to claim

 *   @dealy_ms: delay in ms

 *

 *   Returns %1 if the host is claimed, %0 otherwise.

 */

int mmc_try_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,

		     unsigned int delay_ms)

{

	int claimed_host = 0;

	struct task_struct *task = ctx ? NULL : current;

	unsigned long flags;

	int retry_cnt = delay_ms/10;

	bool pm = false;



	do {

		spin_lock_irqsave(&host->lock, flags);

		if (!host->claimed || mmc_ctx_matches(host, ctx, task)) {

			host->claimed = 1;

			mmc_ctx_set_claimer(host, ctx, task);

			host->claim_cnt += 1;

			claimed_host = 1;

			if (host->claim_cnt == 1)

				pm = true;

		}

		spin_unlock_irqrestore(&host->lock, flags);

		if (!claimed_host)

			mmc_delay(10);

	} while (!claimed_host && retry_cnt--);



	if (pm)

		pm_runtime_get_sync(mmc_dev(host));



	return claimed_host;

}

EXPORT_SYMBOL(mmc_try_claim_host);

#endif



/**

 *	mmc_release_host - release a host

 *	@host: mmc host to release

drivers/mmc/core/core.h

+4 −0
Original line number Diff line number Diff line
@@ -143,6 +143,10 @@ int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen); 


int __mmc_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,

		     atomic_t *abort);

#if defined(CONFIG_SDC_QTI)

int mmc_try_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,

		unsigned int delay_ms);

#endif

void mmc_release_host(struct mmc_host *host);

void mmc_get_card(struct mmc_card *card, struct mmc_ctx *ctx);

void mmc_put_card(struct mmc_card *card, struct mmc_ctx *ctx);

drivers/mmc/core/sd.c

+15 −1
Original line number Diff line number Diff line
@@ -1206,7 +1206,21 @@ static void mmc_sd_detect(struct mmc_host *host) 
{

	int err;



#if defined(CONFIG_SDC_QTI)

	/*

	 * Try to acquire claim host. If failed to get the lock in 2 sec,

	 * just return; This is to ensure that when this call is invoked

	 * due to pm_suspend, not to block suspend for longer duration.

	 */

	pm_runtime_get_sync(&host->card->dev);

	if (!mmc_try_claim_host(host, NULL, 2000)) {

		pm_runtime_mark_last_busy(&host->card->dev);

		pm_runtime_put_autosuspend(&host->card->dev);

		return;

	}

#else

	 mmc_get_card(host->card, NULL);

#endif



	/*

	 * Just check if our card has been removed.