bnx2x: prevent WARN during driver unload

Starting with commit 80c33dd "net: add might_sleep() call to napi_disable"
bnx2x fails the might_sleep tests causing a stack trace to appear whenever
the driver is unloaded, as local_bh_disable() is being called before
napi_disable().

This changes the locking schematics related to CONFIG_NET_RX_BUSY_POLL,
preventing the need for calling local_bh_disable() and thus eliminating
the issue.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index 2d5fce4..ec61190 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -520,10 +520,12 @@ struct bnx2x_fastpath {
 #define BNX2X_FP_STATE_IDLE                  0
 #define BNX2X_FP_STATE_NAPI            (1 << 0)    /* NAPI owns this FP */
 #define BNX2X_FP_STATE_POLL            (1 << 1)    /* poll owns this FP */
-#define BNX2X_FP_STATE_NAPI_YIELD      (1 << 2)    /* NAPI yielded this FP */
-#define BNX2X_FP_STATE_POLL_YIELD      (1 << 3)    /* poll yielded this FP */
+#define BNX2X_FP_STATE_DISABLED                (1 << 2)
+#define BNX2X_FP_STATE_NAPI_YIELD      (1 << 3)    /* NAPI yielded this FP */
+#define BNX2X_FP_STATE_POLL_YIELD      (1 << 4)    /* poll yielded this FP */
+#define BNX2X_FP_OWNED (BNX2X_FP_STATE_NAPI | BNX2X_FP_STATE_POLL)
 #define BNX2X_FP_YIELD (BNX2X_FP_STATE_NAPI_YIELD | BNX2X_FP_STATE_POLL_YIELD)
-#define BNX2X_FP_LOCKED        (BNX2X_FP_STATE_NAPI | BNX2X_FP_STATE_POLL)
+#define BNX2X_FP_LOCKED        (BNX2X_FP_OWNED | BNX2X_FP_STATE_DISABLED)
 #define BNX2X_FP_USER_PEND (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_POLL_YIELD)
        /* protect state */
        spinlock_t lock;
@@ -613,7 +615,7 @@ static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
 {
        bool rc = true;
 
-       spin_lock(&fp->lock);
+       spin_lock_bh(&fp->lock);
        if (fp->state & BNX2X_FP_LOCKED) {
                WARN_ON(fp->state & BNX2X_FP_STATE_NAPI);
                fp->state |= BNX2X_FP_STATE_NAPI_YIELD;
@@ -622,7 +624,7 @@ static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
                /* we don't care if someone yielded */
                fp->state = BNX2X_FP_STATE_NAPI;
        }
-       spin_unlock(&fp->lock);
+       spin_unlock_bh(&fp->lock);
        return rc;
 }
 
@@ -631,14 +633,16 @@ static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
 {
        bool rc = false;
 
-       spin_lock(&fp->lock);
+       spin_lock_bh(&fp->lock);
        WARN_ON(fp->state &
                (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_NAPI_YIELD));
 
        if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
                rc = true;
-       fp->state = BNX2X_FP_STATE_IDLE;
-       spin_unlock(&fp->lock);
+
+       /* state ==> idle, unless currently disabled */
+       fp->state &= BNX2X_FP_STATE_DISABLED;
+       spin_unlock_bh(&fp->lock);
        return rc;
 }
 
@@ -669,7 +673,9 @@ static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
 
        if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
                rc = true;
-       fp->state = BNX2X_FP_STATE_IDLE;
+
+       /* state ==> idle, unless currently disabled */
+       fp->state &= BNX2X_FP_STATE_DISABLED;
        spin_unlock_bh(&fp->lock);
        return rc;
 }
@@ -677,9 +683,23 @@ static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
 /* true if a socket is polling, even if it did not get the lock */
 static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)
 {
-       WARN_ON(!(fp->state & BNX2X_FP_LOCKED));
+       WARN_ON(!(fp->state & BNX2X_FP_OWNED));
        return fp->state & BNX2X_FP_USER_PEND;
 }
+
+/* false if fp is currently owned */
+static inline bool bnx2x_fp_ll_disable(struct bnx2x_fastpath *fp)
+{
+       int rc = true;
+
+       spin_lock_bh(&fp->lock);
+       if (fp->state & BNX2X_FP_OWNED)
+               rc = false;
+       fp->state |= BNX2X_FP_STATE_DISABLED;
+       spin_unlock_bh(&fp->lock);
+
+       return rc;
+}
 #else
 static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp)
 {
@@ -709,6 +729,10 @@ static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)
 {
        return false;
 }
+static inline bool bnx2x_fp_ll_disable(struct bnx2x_fastpath *fp)
+{
+       return true;
+}
 #endif /* CONFIG_NET_RX_BUSY_POLL */
 
 /* Use 2500 as a mini-jumbo MTU for FCoE */

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index ec96130..c6745d7 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -1790,26 +1790,22 @@ static void bnx2x_napi_disable_cnic(struct bnx2x *bp)
 {
        int i;
 
-       local_bh_disable();
        for_each_rx_queue_cnic(bp, i) {
                napi_disable(&bnx2x_fp(bp, i, napi));
-               while (!bnx2x_fp_lock_napi(&bp->fp[i]))
-                       mdelay(1);
+               while (!bnx2x_fp_ll_disable(&bp->fp[i]))
+                       usleep_range(1000, 2000);
        }
-       local_bh_enable();
 }
 
 static void bnx2x_napi_disable(struct bnx2x *bp)
 {
        int i;
 
-       local_bh_disable();
        for_each_eth_queue(bp, i) {
                napi_disable(&bnx2x_fp(bp, i, napi));
-               while (!bnx2x_fp_lock_napi(&bp->fp[i]))
-                       mdelay(1);
+               while (!bnx2x_fp_ll_disable(&bp->fp[i]))
+                       usleep_range(1000, 2000);
        }
-       local_bh_enable();
 }
 
 void bnx2x_netif_start(struct bnx2x *bp)