Card reset is implemented by removing/re-adding the adapter instance.
This is implemented by removing the mmc host, which will then trigger
a cascade of removal callbacks including mwifiex_sdio_remove.
The dead-lock results in the latter function, trying to cancel the work
item executing the mmc host removal. This patch adds a driver level,
not adapter level, work struct to break the dead-lock
Signed-off-by: Andreas Fenkart <afenkart@xxxxxxxxx>
---
drivers/net/wireless/mwifiex/main.h | 1 -
drivers/net/wireless/mwifiex/sdio.c | 63 +++++++++++++++++++++++++++++--------
2 files changed, 50 insertions(+), 14 deletions(-)
diff --git a/drivers/net/wireless/mwifiex/main.h b/drivers/net/wireless/mwifiex/main.h
index f0a6af1..702f348 100644
--- a/drivers/net/wireless/mwifiex/main.h
+++ b/drivers/net/wireless/mwifiex/main.h
@@ -437,7 +437,6 @@ enum rdwr_status {
enum mwifiex_iface_work_flags {
MWIFIEX_IFACE_WORK_FW_DUMP,
- MWIFIEX_IFACE_WORK_CARD_RESET,
};
struct mwifiex_adapter;
diff --git a/drivers/net/wireless/mwifiex/sdio.c b/drivers/net/wireless/mwifiex/sdio.c
index a70e114..0996b0e 100644
--- a/drivers/net/wireless/mwifiex/sdio.c
+++ b/drivers/net/wireless/mwifiex/sdio.c
@@ -75,6 +75,19 @@ static LIST_HEAD(cards);
static DEFINE_MUTEX(cards_mutex);
/*
+ * Card removal will remove the interface then re-add it
+ * Hence the work_struct can't be part of the adapter
+ * otherwise there will be deadlock when we remove the
+ * adapter, and cancel the work struct executing the reset
+ */
+static struct
+{
+ struct work_struct work;
+ struct sdio_mmc_card *card;
+} s_card_reset;
+static DEFINE_SEMAPHORE(s_card_reset_sem);
+
+/*
* SDIO probe.
*
* This function probes an mwifiex device and registers it. It allocates
@@ -1964,10 +1977,36 @@ mwifiex_update_mp_end_port(struct mwifiex_adapter *adapter, u16 port)
port, card->mp_data_port_mask);
}
-static void mwifiex_sdio_card_reset_work(struct mwifiex_adapter *adapter)
+static void mwifiex_sdio_card_reset_work(struct work_struct *work)
{
- struct sdio_mmc_card *card = adapter->card;
- struct mmc_host *target = card->func->card->host;
+ struct sdio_mmc_card *card = NULL;
+ struct mmc_host *target;
+ struct list_head *cur;
+
+ WARN_ON(work != &s_card_reset.work);
+
+ /* adapter pointer might have been invalidated
+ * e.g. card removed from slot
+ */
+ mutex_lock(&cards_mutex);
+ list_for_each_prev(cur, &cards) {
+ card = list_entry(cur, struct sdio_mmc_card, next);
+ if (card == s_card_reset.card)
+ break;
+ }
+ if (!card || card != s_card_reset.card) {
+ pr_err("card was removed, cancel card reset\n");
+ mutex_unlock(&cards_mutex);
+ return;
+ }
+
+ /* card pointer still valid inc ref in host, it's all we need */
+ target = card->func->card->host;
+ mmc_claim_host(target);
+ mutex_unlock(&cards_mutex);
+
+ /* release the work struct, we are done with it */
+ up(&s_card_reset_sem);
/* The actual reset operation must be run outside of driver thread.
* This is because mmc_remove_host() will cause the device to be
@@ -1976,13 +2015,14 @@ static void mwifiex_sdio_card_reset_work(struct mwifiex_adapter *adapter)
*
* We run it in a totally independent workqueue.
*/
-
pr_err("Resetting card...\n");
mmc_remove_host(target);
/* 200ms delay is based on experiment with sdhci controller */
mdelay(200);
target->rescan_entered = 0; /* rescan non-removable cards */
mmc_add_host(target);
+
+ mmc_release_host(target);
}
/* This function read/write firmware */
@@ -2160,9 +2200,6 @@ static void mwifiex_sdio_work(struct work_struct *work)
struct mwifiex_adapter *adapter =
container_of(work, struct mwifiex_adapter, iface_work);
- if (test_and_clear_bit(MWIFIEX_IFACE_WORK_CARD_RESET,
- &adapter->iface_work_flags))
- mwifiex_sdio_card_reset_work(adapter);
if (test_and_clear_bit(MWIFIEX_IFACE_WORK_FW_DUMP,
&adapter->iface_work_flags))
mwifiex_sdio_fw_dump_work(work);
@@ -2171,12 +2208,9 @@ static void mwifiex_sdio_work(struct work_struct *work)
/* This function resets the card */
static void mwifiex_sdio_card_reset(struct mwifiex_adapter *adapter)
{
- if (test_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &adapter->iface_work_flags))
- return;
-
- set_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &adapter->iface_work_flags);
-
- schedule_work(&adapter->iface_work);
+ down(&s_card_reset_sem);
+ s_card_reset.card = adapter->card;
+ schedule_work(&s_card_reset.work);
}
/* This function dumps FW information */
@@ -2317,6 +2351,7 @@ static int
mwifiex_sdio_init_module(void)
{
sema_init(&add_remove_card_sem, 1);
+ INIT_WORK(&s_card_reset.work, mwifiex_sdio_card_reset_work);
/* Clear the flag in case user removes the card. */
user_rmmod = 0;
@@ -2339,6 +2374,8 @@ mwifiex_sdio_cleanup_module(void)
if (!down_interruptible(&add_remove_card_sem))
up(&add_remove_card_sem);
+ cancel_work_sync(&s_card_reset.work);
+
/* Set the flag as user is removing this module. */
user_rmmod = 1;
--
2.1.4
--
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