brcmfmac: simplify dpc handling using atomic operations

Instead of allocating an empty list item and queue that for
the dpc data worker to dequeue an atomic counter is used.

Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
index 6f3d181..d4db0c7 100644 (file)
--- a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
@@ -495,8 +495,7 @@ struct brcmf_sdio {
 
        struct workqueue_struct *brcmf_wq;
        struct work_struct datawork;
-       struct list_head dpc_tsklst;
-       spinlock_t dpc_tl_lock;
+       atomic_t dpc_tskcnt;
 
        const struct firmware *firmware;
        u32 fw_ptr;
@@ -2061,23 +2060,6 @@ static inline void brcmf_sdbrcm_clrintr(struct brcmf_sdio *bus)
        }
 }
 
-static inline void brcmf_sdbrcm_adddpctsk(struct brcmf_sdio *bus)
-{
-       struct list_head *new_hd;
-       unsigned long flags;
-
-       if (in_interrupt())
-               new_hd = kzalloc(sizeof(struct list_head), GFP_ATOMIC);
-       else
-               new_hd = kzalloc(sizeof(struct list_head), GFP_KERNEL);
-       if (new_hd == NULL)
-               return;
-
-       spin_lock_irqsave(&bus->dpc_tl_lock, flags);
-       list_add_tail(new_hd, &bus->dpc_tsklst);
-       spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
-}
-
 static int brcmf_sdio_intr_rstatus(struct brcmf_sdio *bus)
 {
        u8 idx;
@@ -2312,7 +2294,7 @@ static void brcmf_sdbrcm_dpc(struct brcmf_sdio *bus)
                   (!atomic_read(&bus->fcstate) &&
                    brcmu_pktq_mlen(&bus->txq, ~bus->flowcontrol) &&
                    data_ok(bus)) || PKT_AVAILABLE()) {
-               brcmf_sdbrcm_adddpctsk(bus);
+               atomic_inc(&bus->dpc_tskcnt);
        }
 
        /* If we're done for now, turn off clock request. */
@@ -2342,7 +2324,6 @@ static int brcmf_sdbrcm_bus_txdata(struct device *dev, struct sk_buff *pkt)
        struct brcmf_bus *bus_if = dev_get_drvdata(dev);
        struct brcmf_sdio_dev *sdiodev = bus_if->bus_priv.sdio;
        struct brcmf_sdio *bus = sdiodev->bus;
-       unsigned long flags;
 
        brcmf_dbg(TRACE, "Enter\n");
 
@@ -2381,14 +2362,9 @@ static int brcmf_sdbrcm_bus_txdata(struct device *dev, struct sk_buff *pkt)
                qcount[prec] = pktq_plen(&bus->txq, prec);
 #endif
 
-       spin_lock_irqsave(&bus->dpc_tl_lock, flags);
-       if (list_empty(&bus->dpc_tsklst)) {
-               spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
-
-               brcmf_sdbrcm_adddpctsk(bus);
+       if (atomic_read(&bus->dpc_tskcnt) == 0) {
+               atomic_inc(&bus->dpc_tskcnt);
                queue_work(bus->brcmf_wq, &bus->datawork);
-       } else {
-               spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
        }
 
        return ret;
@@ -2525,7 +2501,6 @@ brcmf_sdbrcm_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
        struct brcmf_bus *bus_if = dev_get_drvdata(dev);
        struct brcmf_sdio_dev *sdiodev = bus_if->bus_priv.sdio;
        struct brcmf_sdio *bus = sdiodev->bus;
-       unsigned long flags;
 
        brcmf_dbg(TRACE, "Enter\n");
 
@@ -2612,18 +2587,13 @@ brcmf_sdbrcm_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
                } while (ret < 0 && retries++ < TXRETRIES);
        }
 
-       spin_lock_irqsave(&bus->dpc_tl_lock, flags);
        if ((bus->idletime == BRCMF_IDLE_IMMEDIATE) &&
-           list_empty(&bus->dpc_tsklst)) {
-               spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
-
+           atomic_read(&bus->dpc_tskcnt) == 0) {
                bus->activity = false;
                sdio_claim_host(bus->sdiodev->func[1]);
                brcmf_dbg(INFO, "idle\n");
                brcmf_sdbrcm_clkctl(bus, CLK_NONE, true);
                sdio_release_host(bus->sdiodev->func[1]);
-       } else {
-               spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
        }
 
        if (ret)
@@ -3451,7 +3421,7 @@ void brcmf_sdbrcm_isr(void *arg)
        if (!bus->intr)
                brcmf_err("isr w/o interrupt configured!\n");
 
-       brcmf_sdbrcm_adddpctsk(bus);
+       atomic_inc(&bus->dpc_tskcnt);
        queue_work(bus->brcmf_wq, &bus->datawork);
 }
 
@@ -3460,7 +3430,6 @@ static bool brcmf_sdbrcm_bus_watchdog(struct brcmf_sdio *bus)
 #ifdef DEBUG
        struct brcmf_bus *bus_if = dev_get_drvdata(bus->sdiodev->dev);
 #endif /* DEBUG */
-       unsigned long flags;
 
        brcmf_dbg(TIMER, "Enter\n");
 
@@ -3476,11 +3445,9 @@ static bool brcmf_sdbrcm_bus_watchdog(struct brcmf_sdio *bus)
                if (!bus->intr ||
                    (bus->sdcnt.intrcount == bus->sdcnt.lastintrs)) {
 
-                       spin_lock_irqsave(&bus->dpc_tl_lock, flags);
-                       if (list_empty(&bus->dpc_tsklst)) {
+                       if (atomic_read(&bus->dpc_tskcnt) == 0) {
                                u8 devpend;
-                               spin_unlock_irqrestore(&bus->dpc_tl_lock,
-                                                      flags);
+
                                sdio_claim_host(bus->sdiodev->func[1]);
                                devpend = brcmf_sdio_regrb(bus->sdiodev,
                                                           SDIO_CCCR_INTx,
@@ -3489,9 +3456,6 @@ static bool brcmf_sdbrcm_bus_watchdog(struct brcmf_sdio *bus)
                                intstatus =
                                    devpend & (INTR_STATUS_FUNC1 |
                                               INTR_STATUS_FUNC2);
-                       } else {
-                               spin_unlock_irqrestore(&bus->dpc_tl_lock,
-                                                      flags);
                        }
 
                        /* If there is something, make like the ISR and
@@ -3500,7 +3464,7 @@ static bool brcmf_sdbrcm_bus_watchdog(struct brcmf_sdio *bus)
                                bus->sdcnt.pollcnt++;
                                atomic_set(&bus->ipend, 1);
 
-                               brcmf_sdbrcm_adddpctsk(bus);
+                               atomic_inc(&bus->dpc_tskcnt);
                                queue_work(bus->brcmf_wq, &bus->datawork);
                        }
                }
@@ -3566,20 +3530,11 @@ static void brcmf_sdio_dataworker(struct work_struct *work)
 {
        struct brcmf_sdio *bus = container_of(work, struct brcmf_sdio,
                                              datawork);
-       struct list_head *cur_hd, *tmp_hd;
-       unsigned long flags;
-
-       spin_lock_irqsave(&bus->dpc_tl_lock, flags);
-       list_for_each_safe(cur_hd, tmp_hd, &bus->dpc_tsklst) {
-               spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
 
+       while (atomic_read(&bus->dpc_tskcnt)) {
                brcmf_sdbrcm_dpc(bus);
-
-               spin_lock_irqsave(&bus->dpc_tl_lock, flags);
-               list_del(cur_hd);
-               kfree(cur_hd);
+               atomic_dec(&bus->dpc_tskcnt);
        }
-       spin_unlock_irqrestore(&bus->dpc_tl_lock, flags);
 }
 
 static void brcmf_sdbrcm_release_malloc(struct brcmf_sdio *bus)
@@ -3927,8 +3882,7 @@ void *brcmf_sdbrcm_probe(u32 regsva, struct brcmf_sdio_dev *sdiodev)
                bus->watchdog_tsk = NULL;
        }
        /* Initialize DPC thread */
-       INIT_LIST_HEAD(&bus->dpc_tsklst);
-       spin_lock_init(&bus->dpc_tl_lock);
+       atomic_set(&bus->dpc_tskcnt, 0);
 
        /* Assign bus interface call back */
        bus->sdiodev->bus_if->dev = bus->sdiodev->dev;