wlcore: Use spin_trylock in wlcore_irq_locked() for running the queue

We currently have a collection of flags and locking between the
threaded irq and tx work:

- wl->flags bitops
- wl->mutex
- wl->wl_lock spinlock

The bitops flags do not need a spinlock around them, and
wlcore_irq() already holds the mutex calling wlcore_irq_locked().
And we only need the spinlock to see if we need to run the queue
or not.

To simplify the locking, we can use spin_trylock and always run the
tx queue unless we know there's nothing to do.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200702162951.45392-3-tony@atomide.com

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
index 437ddb89ad9c76f6949873a37e22eccff8e7097f..458457cbab59ce22a1494fca967b7d518dcce201 100644 (file)
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -521,6 +521,7 @@ static int wlcore_irq_locked(struct wl1271 *wl)
        int ret = 0;
        u32 intr;
        int loopcount = WL1271_IRQ_MAX_LOOPS;
+       bool run_tx_queue = true;
        bool done = false;
        unsigned int defer_count;
        unsigned long flags;
@@ -586,19 +587,22 @@ static int wlcore_irq_locked(struct wl1271 *wl)
                                goto err_ret;
 
                        /* Check if any tx blocks were freed */
-                       spin_lock_irqsave(&wl->wl_lock, flags);
-                       if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
-                           wl1271_tx_total_queue_count(wl) > 0) {
-                               spin_unlock_irqrestore(&wl->wl_lock, flags);
+                       if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags)) {
+                               if (spin_trylock_irqsave(&wl->wl_lock, flags)) {
+                                       if (!wl1271_tx_total_queue_count(wl))
+                                               run_tx_queue = false;
+                                       spin_unlock_irqrestore(&wl->wl_lock, flags);
+                               }
+
                                /*
                                 * In order to avoid starvation of the TX path,
                                 * call the work function directly.
                                 */
-                               ret = wlcore_tx_work_locked(wl);
-                               if (ret < 0)
-                                       goto err_ret;
-                       } else {
-                               spin_unlock_irqrestore(&wl->wl_lock, flags);
+                               if (run_tx_queue) {
+                                       ret = wlcore_tx_work_locked(wl);
+                                       if (ret < 0)
+                                               goto err_ret;
+                               }
                        }
 
                        /* check for tx results */