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>

1 files changed, 12 insertions, 58 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
index 6f3d181659ef..d4db0c7cd692 100644
--- 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;