On 28/04/2016 9:29 p.m., Ulf Hansson wrote:
For the reasons explained below, it's safe to remove the rescan_disable
flag.
1)
cancel_delayed_work_sync() prevents an executing work from re-scheduling
itself.
2)
We are using the system_freezable_wq for the rescan works. As that queue
becomes frozen when userspace becomes frozen during system PM, we don't
need to disable the rescan works in the PM_SUSPEND_PREPARE phase.
What about the case when a SDIO card has to be removed? Seems like a rescan
could theoretically get scheduled and run before the workqueue is frozen.
3)
At host registration it's not safe to schedule a detect work until
mmc_start_host() is invoked. Trying to use the rescan_disable flag to
prevent a rescan work from being executed isn't helping.
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
Changes in v2:
Updated changelog to better reflect why rescan_flag is redundant.
---
drivers/mmc/core/core.c | 12 ------------
drivers/mmc/core/host.c | 3 ---
include/linux/mmc/host.h | 1 -
3 files changed, 16 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 99275e4..b8c6a11 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2580,9 +2580,6 @@ void mmc_rescan(struct work_struct *work)
container_of(work, struct mmc_host, detect.work);
int i;
- if (host->rescan_disable)
- return;
-
/* If there is a non-removable card registered, only scan once */
if (!mmc_card_is_removable(host) && host->rescan_entered)
return;
@@ -2649,7 +2646,6 @@ void mmc_rescan(struct work_struct *work)
void mmc_start_host(struct mmc_host *host)
{
host->f_init = max(freqs[0], host->f_min);
- host->rescan_disable = 0;
host->ios.power_mode = MMC_POWER_UNDEFINED;
mmc_claim_host(host);
@@ -2674,7 +2670,6 @@ void mmc_stop_host(struct mmc_host *host)
if (host->slot.cd_irq >= 0)
disable_irq(host->slot.cd_irq);
- host->rescan_disable = 1;
cancel_delayed_work_sync(&host->detect);
/* clear pm flags now and let card drivers set them as needed */
@@ -2788,9 +2783,6 @@ static int mmc_pm_notify(struct notifier_block *notify_block,
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
case PM_RESTORE_PREPARE:
- spin_lock_irqsave(&host->lock, flags);
- host->rescan_disable = 1;
- spin_unlock_irqrestore(&host->lock, flags);
cancel_delayed_work_sync(&host->detect);
if (!host->bus_ops)
@@ -2814,10 +2806,6 @@ static int mmc_pm_notify(struct notifier_block *notify_block,
case PM_POST_SUSPEND:
case PM_POST_HIBERNATION:
case PM_POST_RESTORE:
-
- spin_lock_irqsave(&host->lock, flags);
- host->rescan_disable = 0;
- spin_unlock_irqrestore(&host->lock, flags);
_mmc_detect_change(host, 0, false);
}
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index e0a3ee1..e972489 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -319,9 +319,6 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
if (!host)
return NULL;
- /* scanning will be enabled when we're ready */
- host->rescan_disable = 1;
-
again:
if (!ida_pre_get(&mmc_host_ida, GFP_KERNEL)) {
kfree(host);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 85800b4..7fbe5c0 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -330,7 +330,6 @@ struct mmc_host {
unsigned int doing_retune:1; /* re-tuning in progress */
unsigned int retune_now:1; /* do re-tuning at next req */
- int rescan_disable; /* disable card detection */
int rescan_entered; /* used with nonremovable devices */
int need_retune; /* re-tuning is needed */
--
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