From: Raja Mani <rmani@xxxxxxxxxxxxxxxx>
The commit "ath6kl: Use a mutex_lock to avoid
race in diabling and handling irq" introduces a
state where ath6kl_sdio_irq_handler() would be waiting
to claim the sdio function for receive indefinitely
when things happen in the following order.
ath6kl_sdio_irq_handler()
- aquires mtx_irq
- sdio_release_host()
ath6kl_sdio_irq_disable()
- sdio_claim_host()
- sleep on mtx_irq
ath6kl_hif_intr_bh_handler()
- (indefinitely) wait for the sdio
function to be released to exclusively claim
it again for receive operation.
Fix this by replacing the mtx_irq with an atomic
variable and a wait_queue.
Signed-off-by: Raja Mani <rmani@xxxxxxxxxxxxxxxx>
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@xxxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath6kl/sdio.c | 27 +++++++++++++++++++--------
1 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/net/wireless/ath/ath6kl/sdio.c b/drivers/net/wireless/ath/ath6kl/sdio.c
index f4306e4..a7c0d8d 100644
--- a/drivers/net/wireless/ath/ath6kl/sdio.c
+++ b/drivers/net/wireless/ath/ath6kl/sdio.c
@@ -49,8 +49,8 @@ struct ath6kl_sdio {
/* scatter request list head */
struct list_head scat_req;
- /* Avoids disabling irq while the interrupts being handled */
- struct mutex mtx_irq;
+ atomic_t irq_handling;
+ wait_queue_head_t irq_wq;
spinlock_t scat_lock;
bool scatter_enabled;
@@ -462,7 +462,7 @@ static void ath6kl_sdio_irq_handler(struct sdio_func *func)
ath6kl_dbg(ATH6KL_DBG_SDIO, "irq\n");
ar_sdio = sdio_get_drvdata(func);
- mutex_lock(&ar_sdio->mtx_irq);
+ atomic_set(&ar_sdio->irq_handling, 1);
/*
* Release the host during interrups so we can pick it back up when
* we process commands.
@@ -471,7 +471,10 @@ static void ath6kl_sdio_irq_handler(struct sdio_func *func)
status = ath6kl_hif_intr_bh_handler(ar_sdio->ar);
sdio_claim_host(ar_sdio->func);
- mutex_unlock(&ar_sdio->mtx_irq);
+
+ atomic_set(&ar_sdio->irq_handling, 0);
+ wake_up(&ar_sdio->irq_wq);
+
WARN_ON(status && status != -ECANCELED);
}
@@ -579,14 +582,21 @@ static void ath6kl_sdio_irq_disable(struct ath6kl *ar)
sdio_claim_host(ar_sdio->func);
- mutex_lock(&ar_sdio->mtx_irq);
+ if (atomic_read(&ar_sdio->irq_handling)) {
+ sdio_release_host(ar_sdio->func);
+
+ ret = wait_event_interruptible(ar_sdio->irq_wq,
+ !atomic_read(&ar_sdio->irq_handling));
+ if (ret)
+ return;
+
+ sdio_claim_host(ar_sdio->func);
+ }
ret = sdio_release_irq(ar_sdio->func);
if (ret)
ath6kl_err("Failed to release sdio irq: %d\n", ret);
- mutex_unlock(&ar_sdio->mtx_irq);
-
sdio_release_host(ar_sdio->func);
}
@@ -1285,7 +1295,6 @@ static int ath6kl_sdio_probe(struct sdio_func *func,
spin_lock_init(&ar_sdio->scat_lock);
spin_lock_init(&ar_sdio->wr_async_lock);
mutex_init(&ar_sdio->dma_buffer_mutex);
- mutex_init(&ar_sdio->mtx_irq);
INIT_LIST_HEAD(&ar_sdio->scat_req);
INIT_LIST_HEAD(&ar_sdio->bus_req_freeq);
@@ -1293,6 +1302,8 @@ static int ath6kl_sdio_probe(struct sdio_func *func,
INIT_WORK(&ar_sdio->wr_async_work, ath6kl_sdio_write_async_work);
+ init_waitqueue_head(&ar_sdio->irq_wq);
+
for (count = 0; count < BUS_REQUEST_MAX_NUM; count++)
ath6kl_sdio_free_bus_req(ar_sdio, &ar_sdio->bus_req[count]);
--
1.7.0.4
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