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authorRaja Mani <rmani@qca.qualcomm.com>2012-02-09 08:27:12 +0100
committerKalle Valo <kvalo@qca.qualcomm.com>2012-03-01 08:34:12 +0100
commitd1f4159723450252b643bcddff064153f32918bc (patch)
treee9431ed202bf979681c027106e93b72b86db4ef4
parentath6kl: Collect residue firmware logs (diff)
downloadlinux-d1f4159723450252b643bcddff064153f32918bc.tar.xz
linux-d1f4159723450252b643bcddff064153f32918bc.zip
ath6kl: Fix random system lockup
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. kvalo: add ath6kl_sdio_is_on_irq() due to open parenthesis alignment Signed-off-by: Raja Mani <rmani@qca.qualcomm.com> Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com> Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
-rw-r--r--drivers/net/wireless/ath/ath6kl/sdio.c34
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/net/wireless/ath/ath6kl/sdio.c b/drivers/net/wireless/ath/ath6kl/sdio.c
index cae446bf2129..346f5dd3a954 100644
--- a/drivers/net/wireless/ath/ath6kl/sdio.c
+++ b/drivers/net/wireless/ath/ath6kl/sdio.c
@@ -50,8 +50,8 @@ 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;
@@ -463,7 +463,7 @@ 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.
@@ -472,7 +472,10 @@ 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);
}
@@ -573,6 +576,13 @@ static void ath6kl_sdio_irq_enable(struct ath6kl *ar)
sdio_release_host(ar_sdio->func);
}
+static bool ath6kl_sdio_is_on_irq(struct ath6kl *ar)
+{
+ struct ath6kl_sdio *ar_sdio = ath6kl_sdio_priv(ar);
+
+ return !atomic_read(&ar_sdio->irq_handling);
+}
+
static void ath6kl_sdio_irq_disable(struct ath6kl *ar)
{
struct ath6kl_sdio *ar_sdio = ath6kl_sdio_priv(ar);
@@ -580,14 +590,21 @@ 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,
+ ath6kl_sdio_is_on_irq(ar));
+ 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);
}
@@ -1288,7 +1305,6 @@ 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);
@@ -1296,6 +1312,8 @@ 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]);