diff mbox

[net,v5,1/5] bnx2x: protect different statistics flows

Message ID 1376349903-3461-2-git-send-email-dmitry@broadcom.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Dmitry Kravkov Aug. 12, 2013, 11:24 p.m. UTC 
Add locking to protect different statistics flows from
running simultaneously.
This in order to serialize statistics requests sent to FW,
otherwise two outstanding queries may cause FW assert.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x.h       |  2 +
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c  |  1 +
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c | 66 ++++++++++++++++++-----
 3 files changed, 57 insertions(+), 12 deletions(-)

Comments

Stephen Hemminger Aug. 13, 2013, 12:12 a.m. UTC | #1 
On Tue, 13 Aug 2013 02:24:59 +0300
"Dmitry Kravkov" <dmitry@broadcom.com> wrote:

> +	bool					stats_started;
> +	struct semaphore			stats_sema;

Is there a reason to use a counting semaphore? Do you expect it to
be held across user process boundary? or want count > 1?

Use of semaphores as a locking primitive is discouraged,
instead us a mutex.
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David Miller Aug. 13, 2013, 4:24 a.m. UTC | #2 
From: Stephen Hemminger <stephen@networkplumber.org>
Date: Mon, 12 Aug 2013 17:12:08 -0700

> On Tue, 13 Aug 2013 02:24:59 +0300
> "Dmitry Kravkov" <dmitry@broadcom.com> wrote:
> 
>> +	bool					stats_started;
>> +	struct semaphore			stats_sema;
> 
> Is there a reason to use a counting semaphore? Do you expect it to
> be held across user process boundary? or want count > 1?
> 
> Use of semaphores as a locking primitive is discouraged,
> instead us a mutex.

Would you please look at the feedback I gave these guys to the
previous iteration of these changes?

They were using custom locking primitives and semaphores gave
the best approximation to the semantics they were looking for.

Thanks.
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Neal Cardwell Aug. 13, 2013, 5:54 p.m. UTC | #3 
On Mon, Aug 12, 2013 at 7:24 PM, Dmitry Kravkov <dmitry@broadcom.com> wrote:
> Add locking to protect different statistics flows from
> running simultaneously.
> This in order to serialize statistics requests sent to FW,
> otherwise two outstanding queries may cause FW assert.
>
> Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
> Signed-off-by: Ariel Elior <ariele@broadcom.com>
> Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
> ---
>  drivers/net/ethernet/broadcom/bnx2x/bnx2x.h       |  2 +
>  drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c  |  1 +
>  drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c | 66 ++++++++++++++++++-----
>  3 files changed, 57 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
> index d80e34b..98be67f 100644

Acked-by: Neal Cardwell <ncardwell@google.com>

Thanks!

neal
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Stephen Hemminger Aug. 13, 2013, 5:57 p.m. UTC | #4 
On Mon, 12 Aug 2013 21:24:02 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:

> From: Stephen Hemminger <stephen@networkplumber.org>
> Date: Mon, 12 Aug 2013 17:12:08 -0700
> 
> > On Tue, 13 Aug 2013 02:24:59 +0300
> > "Dmitry Kravkov" <dmitry@broadcom.com> wrote:
> > 
> >> +	bool					stats_started;
> >> +	struct semaphore			stats_sema;
> > 
> > Is there a reason to use a counting semaphore? Do you expect it to
> > be held across user process boundary? or want count > 1?
> > 
> > Use of semaphores as a locking primitive is discouraged,
> > instead us a mutex.
> 
> Would you please look at the feedback I gave these guys to the
> previous iteration of these changes?
> 
> They were using custom locking primitives and semaphores gave
> the best approximation to the semantics they were looking for.

Your right in this case sempahore makes sense because it is
used to hold off process while hardware responds.
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diff mbox

Patch

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index d80e34b..98be67f 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -1830,6 +1830,8 @@  struct bnx2x {
 
 	int fp_array_size;
 	u32 dump_preset_idx;
+	bool					stats_started;
+	struct semaphore			stats_sema;
 };
 
 /* Tx queues may be less or equal to Rx queues */
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index e06186c..6e1e9e7 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -11524,6 +11524,7 @@  static int bnx2x_init_bp(struct bnx2x *bp)
 	mutex_init(&bp->port.phy_mutex);
 	mutex_init(&bp->fw_mb_mutex);
 	spin_lock_init(&bp->stats_lock);
+	sema_init(&bp->stats_sema, 1);
 
 	INIT_DELAYED_WORK(&bp->sp_task, bnx2x_sp_task);
 	INIT_DELAYED_WORK(&bp->sp_rtnl_task, bnx2x_sp_rtnl_task);
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
index 98366ab..d63d132 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
@@ -221,7 +221,8 @@  static int bnx2x_stats_comp(struct bnx2x *bp)
  * Statistics service functions
  */
 
-static void bnx2x_stats_pmf_update(struct bnx2x *bp)
+/* should be called under stats_sema */
+static void __bnx2x_stats_pmf_update(struct bnx2x *bp)
 {
 	struct dmae_command *dmae;
 	u32 opcode;
@@ -518,7 +519,8 @@  static void bnx2x_func_stats_init(struct bnx2x *bp)
 	*stats_comp = 0;
 }
 
-static void bnx2x_stats_start(struct bnx2x *bp)
+/* should be called under stats_sema */
+static void __bnx2x_stats_start(struct bnx2x *bp)
 {
 	/* vfs travel through here as part of the statistics FSM, but no action
 	 * is required
@@ -534,13 +536,34 @@  static void bnx2x_stats_start(struct bnx2x *bp)
 
 	bnx2x_hw_stats_post(bp);
 	bnx2x_storm_stats_post(bp);
+
+	bp->stats_started = true;
+}
+
+static void bnx2x_stats_start(struct bnx2x *bp)
+{
+	if (down_timeout(&bp->stats_sema, HZ/10))
+		BNX2X_ERR("Unable to acquire stats lock\n");
+	__bnx2x_stats_start(bp);
+	up(&bp->stats_sema);
 }
 
 static void bnx2x_stats_pmf_start(struct bnx2x *bp)
 {
+	if (down_timeout(&bp->stats_sema, HZ/10))
+		BNX2X_ERR("Unable to acquire stats lock\n");
 	bnx2x_stats_comp(bp);
-	bnx2x_stats_pmf_update(bp);
-	bnx2x_stats_start(bp);
+	__bnx2x_stats_pmf_update(bp);
+	__bnx2x_stats_start(bp);
+	up(&bp->stats_sema);
+}
+
+static void bnx2x_stats_pmf_update(struct bnx2x *bp)
+{
+	if (down_timeout(&bp->stats_sema, HZ/10))
+		BNX2X_ERR("Unable to acquire stats lock\n");
+	__bnx2x_stats_pmf_update(bp);
+	up(&bp->stats_sema);
 }
 
 static void bnx2x_stats_restart(struct bnx2x *bp)
@@ -550,8 +573,11 @@  static void bnx2x_stats_restart(struct bnx2x *bp)
 	 */
 	if (IS_VF(bp))
 		return;
+	if (down_timeout(&bp->stats_sema, HZ/10))
+		BNX2X_ERR("Unable to acquire stats lock\n");
 	bnx2x_stats_comp(bp);
-	bnx2x_stats_start(bp);
+	__bnx2x_stats_start(bp);
+	up(&bp->stats_sema);
 }
 
 static void bnx2x_bmac_stats_update(struct bnx2x *bp)
@@ -888,9 +914,7 @@  static int bnx2x_storm_stats_validate_counters(struct bnx2x *bp)
 	/* Make sure we use the value of the counter
 	 * used for sending the last stats ramrod.
 	 */
-	spin_lock_bh(&bp->stats_lock);
 	cur_stats_counter = bp->stats_counter - 1;
-	spin_unlock_bh(&bp->stats_lock);
 
 	/* are storm stats valid? */
 	if (le16_to_cpu(counters->xstats_counter) != cur_stats_counter) {
@@ -1227,12 +1251,18 @@  static void bnx2x_stats_update(struct bnx2x *bp)
 {
 	u32 *stats_comp = bnx2x_sp(bp, stats_comp);
 
-	if (bnx2x_edebug_stats_stopped(bp))
+	/* we run update from timer context, so give up
+	 * if somebody is in the middle of transition
+	 */
+	if (down_trylock(&bp->stats_sema))
 		return;
 
+	if (bnx2x_edebug_stats_stopped(bp) || !bp->stats_started)
+		goto out;
+
 	if (IS_PF(bp)) {
 		if (*stats_comp != DMAE_COMP_VAL)
-			return;
+			goto out;
 
 		if (bp->port.pmf)
 			bnx2x_hw_stats_update(bp);
@@ -1242,7 +1272,7 @@  static void bnx2x_stats_update(struct bnx2x *bp)
 				BNX2X_ERR("storm stats were not updated for 3 times\n");
 				bnx2x_panic();
 			}
-			return;
+			goto out;
 		}
 	} else {
 		/* vf doesn't collect HW statistics, and doesn't get completions
@@ -1256,7 +1286,7 @@  static void bnx2x_stats_update(struct bnx2x *bp)
 
 	/* vf is done */
 	if (IS_VF(bp))
-		return;
+		goto out;
 
 	if (netif_msg_timer(bp)) {
 		struct bnx2x_eth_stats *estats = &bp->eth_stats;
@@ -1267,6 +1297,9 @@  static void bnx2x_stats_update(struct bnx2x *bp)
 
 	bnx2x_hw_stats_post(bp);
 	bnx2x_storm_stats_post(bp);
+
+out:
+	up(&bp->stats_sema);
 }
 
 static void bnx2x_port_stats_stop(struct bnx2x *bp)
@@ -1332,6 +1365,11 @@  static void bnx2x_stats_stop(struct bnx2x *bp)
 {
 	int update = 0;
 
+	if (down_timeout(&bp->stats_sema, HZ/10))
+		BNX2X_ERR("Unable to acquire stats lock\n");
+
+	bp->stats_started = false;
+
 	bnx2x_stats_comp(bp);
 
 	if (bp->port.pmf)
@@ -1348,6 +1386,8 @@  static void bnx2x_stats_stop(struct bnx2x *bp)
 		bnx2x_hw_stats_post(bp);
 		bnx2x_stats_comp(bp);
 	}
+
+	up(&bp->stats_sema);
 }
 
 static void bnx2x_stats_do_nothing(struct bnx2x *bp)
@@ -1376,15 +1416,17 @@  static const struct {
 void bnx2x_stats_handle(struct bnx2x *bp, enum bnx2x_stats_event event)
 {
 	enum bnx2x_stats_state state;
+	void (*action)(struct bnx2x *bp);
 	if (unlikely(bp->panic))
 		return;
 
 	spin_lock_bh(&bp->stats_lock);
 	state = bp->stats_state;
 	bp->stats_state = bnx2x_stats_stm[state][event].next_state;
+	action = bnx2x_stats_stm[state][event].action;
 	spin_unlock_bh(&bp->stats_lock);
 
-	bnx2x_stats_stm[state][event].action(bp);
+	action(bp);
 
 	if ((event != STATS_EVENT_UPDATE) || netif_msg_timer(bp))
 		DP(BNX2X_MSG_STATS, "state %d -> event %d -> state %d\n",