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From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: David Marchand <david.marchand@redhat.com>,
	"Xia, Chenbo" <chenbo.xia@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"thomas@monjalon.net" <thomas@monjalon.net>
Subject: Re: [PATCH v2 11/20] net/virtio: annotate lock for guest announce
Date: Mon, 27 Feb 2023 17:28:09 +0100	[thread overview]
Message-ID: <debfcb61-61f0-d311-7e8c-c01e20132fbc@redhat.com> (raw)
In-Reply-To: <CAJFAV8zgc6dWqRuyrsC6kbbU7pPL6_uYG8Q_GgD7QWhbTJmvhQ@mail.gmail.com>

Hi,

On 2/27/23 09:24, David Marchand wrote:
> Hello Chenbo,
> 
> Adding Maxime too.
> 
> On Mon, Feb 27, 2023 at 3:05 AM Xia, Chenbo <chenbo.xia@intel.com> wrote:
>>> @@ -1217,7 +1217,7 @@ virtio_notify_peers(struct rte_eth_dev *dev)
>>>        }
>>>
>>>        /* If virtio port just stopped, no need to send RARP */
>>> -     if (virtio_dev_pause(dev) < 0) {
>>> +     if (virtio_dev_pause(dev) != 0) {
>>>                rte_pktmbuf_free(rarp_mbuf);
>>>                return;
>>>        }
>>> diff --git a/drivers/net/virtio/virtio_ethdev.h
>>> b/drivers/net/virtio/virtio_ethdev.h
>>> index c08f382791..ece0130603 100644
>>> --- a/drivers/net/virtio/virtio_ethdev.h
>>> +++ b/drivers/net/virtio/virtio_ethdev.h
>>> @@ -112,8 +112,11 @@ int eth_virtio_dev_init(struct rte_eth_dev *eth_dev);
>>>
>>>   void virtio_interrupt_handler(void *param);
>>>
>>> -int virtio_dev_pause(struct rte_eth_dev *dev);
>>> -void virtio_dev_resume(struct rte_eth_dev *dev);
>>> +#define VIRTIO_DEV_TO_HW(dev) ((struct virtio_hw *)(dev)->data-
>>>> dev_private)
>>> +int virtio_dev_pause(struct rte_eth_dev *dev)
>>> +     __rte_exclusive_trylock_function(0, &VIRTIO_DEV_TO_HW(dev)-
>>>> state_lock);
>>
>> Just curious, why this is trylock instead of lock?
> 
> I wrote this patch some time ago.
> At the time, I must say that I preferred removing those helpers (the
> only caller is virtio_notify_peers()).
> It seems those helpers were added as a kind of api for future
> usecases, it seemed a reason for keeping them.
> So I changed my mind and just annotated them.
> 
> 
> For your question, annotating with "lock" would tell clang that the
> function always takes the lock, regardless of the function return
> value.
> 
> One alternative to this patch could be to always take the lock
> (+annotate dev_pause as "lock"), and have the caller release the lock
> if != 0 return value.
> But it seems counterintuitive to me.
> 
> WDYT?
> 
> 

As discussed with David off-list, I think we could simplify and inline 
virtio_dev_pause()/virtio_dev_resume() into virtio_notify_peers() since 
there are no other users of these functions (see below).

Any objection?

diff --git a/drivers/net/virtio/virtio_ethdev.c 
b/drivers/net/virtio/virtio_ethdev.c
index 0103d95920..dbd84e25ea 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1144,43 +1144,10 @@ virtio_ethdev_negotiate_features(struct 
virtio_hw *hw, uint64_t req_features)
         return 0;
  }

-int
-virtio_dev_pause(struct rte_eth_dev *dev)
-{
-       struct virtio_hw *hw = dev->data->dev_private;
-
-       rte_spinlock_lock(&hw->state_lock);
-
-       if (hw->started == 0) {
-               /* Device is just stopped. */
-               rte_spinlock_unlock(&hw->state_lock);
-               return -1;
-       }
-       hw->started = 0;
-       /*
-        * Prevent the worker threads from touching queues to avoid 
contention,
-        * 1 ms should be enough for the ongoing Tx function to finish.
-        */
-       rte_delay_ms(1);
-       return 0;
-}
-
-/*
- * Recover hw state to let the worker threads continue.
- */
-void
-virtio_dev_resume(struct rte_eth_dev *dev)
-{
-       struct virtio_hw *hw = dev->data->dev_private;
-
-       hw->started = 1;
-       rte_spinlock_unlock(&hw->state_lock);
-}
-
  /*
   * Should be called only after device is paused.
   */
-int
+static int
  virtio_inject_pkts(struct rte_eth_dev *dev, struct rte_mbuf **tx_pkts,
                 int nb_pkts)
  {
@@ -1216,14 +1183,25 @@ virtio_notify_peers(struct rte_eth_dev *dev)
                 return;
         }

-       /* If virtio port just stopped, no need to send RARP */
-       if (virtio_dev_pause(dev) < 0) {
+       rte_spinlock_lock(&hw->state_lock);
+
+       if (hw->started == 0) {
+               /* If virtio port just stopped, no need to send RARP */
                 rte_pktmbuf_free(rarp_mbuf);
-               return;
+               goto out_unlock;
         }

+       /*
+        * Prevent the worker threads from touching queues to avoid 
contention,
+        * 1 ms should be enough for the ongoing Tx function to finish.
+        */
+       rte_delay_ms(1);
+
         virtio_inject_pkts(dev, &rarp_mbuf, 1);
-       virtio_dev_resume(dev);
+       hw->started = 1;
+
+out_unlock:
+       rte_spinlock_unlock(&hw->state_lock);
  }

  static void
diff --git a/drivers/net/virtio/virtio_ethdev.h 
b/drivers/net/virtio/virtio_ethdev.h
index c08f382791..7be1c9acd0 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -112,12 +112,8 @@ int eth_virtio_dev_init(struct rte_eth_dev *eth_dev);

  void virtio_interrupt_handler(void *param);

-int virtio_dev_pause(struct rte_eth_dev *dev);
-void virtio_dev_resume(struct rte_eth_dev *dev);
  int virtio_dev_stop(struct rte_eth_dev *dev);
  int virtio_dev_close(struct rte_eth_dev *dev);
-int virtio_inject_pkts(struct rte_eth_dev *dev, struct rte_mbuf **tx_pkts,
-               int nb_pkts);

  bool virtio_rx_check_scatter(uint16_t max_rx_pkt_len, uint16_t 
rx_buf_size,
                         bool rx_scatter_enabled, const char **error);


  reply	other threads:[~2023-02-27 16:28 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-24  8:16 [PATCH 00/14] Enable lock annotations on most libraries and drivers David Marchand
2023-02-24  8:16 ` [PATCH 01/14] malloc: rework heap lock handling David Marchand
2023-02-24  8:16 ` [PATCH 02/14] mem: rework malloc heap init David Marchand
2023-02-24  8:16 ` [PATCH 03/14] mem: annotate shared memory config locks David Marchand
2023-02-24  8:16 ` [PATCH 04/14] hash: annotate cuckoo hash lock David Marchand
2023-02-24  8:16 ` [PATCH 05/14] graph: annotate graph lock David Marchand
2023-02-24  8:16 ` [PATCH 06/14] drivers: inherit lock annotations for Intel drivers David Marchand
2023-02-24  8:16 ` [PATCH 07/14] net/cxgbe: inherit lock annotations David Marchand
2023-02-24  8:16 ` [PATCH 08/14] net/fm10k: annotate mailbox lock David Marchand
2023-02-24  8:16 ` [PATCH 09/14] net/sfc: rework locking in proxy code David Marchand
2023-02-24  8:16 ` [PATCH 10/14] net/sfc: inherit lock annotations David Marchand
2023-02-24  8:16 ` [PATCH 11/14] net/virtio: annotate lock for guest announce David Marchand
2023-02-24  8:16 ` [PATCH 12/14] raw/ifpga: inherit lock annotations David Marchand
2023-02-24  8:16 ` [PATCH 13/14] vdpa/sfc: " David Marchand
2023-02-24  8:16 ` [PATCH 14/14] enable lock check David Marchand
2023-02-24 15:11 ` [PATCH v2 00/20] Enable lock annotations on most libraries and drivers David Marchand
2023-02-24 15:11   ` [PATCH v2 01/20] malloc: rework heap lock handling David Marchand
2023-02-24 15:11   ` [PATCH v2 02/20] mem: rework malloc heap init David Marchand
2023-02-24 15:11   ` [PATCH v2 03/20] mem: annotate shared memory config locks David Marchand
2023-02-24 15:11   ` [PATCH v2 04/20] hash: annotate cuckoo hash lock David Marchand
2023-02-24 15:11   ` [PATCH v2 05/20] graph: annotate graph lock David Marchand
2023-02-24 15:11   ` [PATCH v2 06/20] drivers: inherit lock annotations for Intel drivers David Marchand
2023-02-24 15:11   ` [PATCH v2 07/20] net/cxgbe: inherit lock annotations David Marchand
2023-02-24 15:11   ` [PATCH v2 08/20] net/fm10k: annotate mailbox lock David Marchand
2023-02-24 15:11   ` [PATCH v2 09/20] net/sfc: rework locking in proxy code David Marchand
2023-02-24 15:11   ` [PATCH v2 10/20] net/sfc: inherit lock annotations David Marchand
2023-02-24 15:11   ` [PATCH v2 11/20] net/virtio: annotate lock for guest announce David Marchand
2023-02-27  2:05     ` Xia, Chenbo
2023-02-27  8:24       ` David Marchand
2023-02-27 16:28         ` Maxime Coquelin [this message]
2023-02-28  2:45           ` Xia, Chenbo
2023-03-02  9:26           ` David Marchand
2023-03-02  9:28             ` Maxime Coquelin
2023-03-02 12:35               ` David Marchand
2023-02-24 15:11   ` [PATCH v2 12/20] raw/ifpga: inherit lock annotations David Marchand
2023-02-27  6:29     ` Xu, Rosen
2023-02-27  7:15       ` Huang, Wei
2023-02-24 15:11   ` [PATCH v2 13/20] vdpa/sfc: " David Marchand
2023-02-24 15:11   ` [PATCH v2 14/20] ipc: annotate pthread mutex David Marchand
2023-02-24 15:11   ` [PATCH v2 15/20] ethdev: " David Marchand
2023-02-24 15:11   ` [PATCH v2 16/20] net/failsafe: fix mutex locking David Marchand
2023-02-24 15:35     ` Gaëtan Rivet
2023-02-24 15:11   ` [PATCH v2 17/20] net/failsafe: annotate pthread mutex David Marchand
2023-02-24 15:11   ` [PATCH v2 18/20] net/hinic: " David Marchand
2023-02-24 15:11   ` [PATCH v2 19/20] eal/windows: disable lock check on alarm code David Marchand
2023-02-24 15:11   ` [PATCH v2 20/20] enable lock check David Marchand
2023-02-27  2:32     ` Xia, Chenbo
2023-02-24 15:58   ` [PATCH v2 00/20] Enable lock annotations on most libraries and drivers Gaëtan Rivet
2023-02-25 10:16     ` David Marchand
2023-02-27 16:12       ` Gaëtan Rivet
2023-03-02  8:52         ` David Marchand
2023-04-03 10:52           ` David Marchand
2023-04-03 15:03             ` Tyler Retzlaff
2023-04-03 15:36             ` Tyler Retzlaff
2023-04-04  7:45               ` David Marchand
2023-04-04 12:48 ` [PATCH v3 00/16] " David Marchand
2023-04-04 12:48   ` [PATCH v3 01/16] malloc: rework heap destroy David Marchand
2023-04-04 12:48   ` [PATCH v3 02/16] mem: rework malloc heap init David Marchand
2023-04-04 12:48   ` [PATCH v3 03/16] mem: annotate shared memory config locks David Marchand
2023-04-04 12:48   ` [PATCH v3 04/16] hash: annotate cuckoo hash lock David Marchand
2023-04-04 12:48   ` [PATCH v3 05/16] graph: annotate graph lock David Marchand
2023-04-04 12:48   ` [PATCH v3 06/16] drivers: inherit lock annotations for Intel drivers David Marchand
2023-04-04 12:48   ` [PATCH v3 07/16] net/cxgbe: inherit lock annotations David Marchand
2023-04-04 12:48   ` [PATCH v3 08/16] net/fm10k: annotate mailbox lock David Marchand
2023-04-04 12:48   ` [PATCH v3 09/16] net/sfc: rework locking in proxy code David Marchand
2023-04-04 12:48   ` [PATCH v3 10/16] net/sfc: inherit lock annotations David Marchand
2023-04-04 12:48   ` [PATCH v3 11/16] net/virtio: rework guest announce notify helper David Marchand
2023-04-04 12:48   ` [PATCH v3 12/16] raw/ifpga: inherit lock annotations David Marchand
2023-04-04 12:48   ` [PATCH v3 13/16] vdpa/sfc: " David Marchand
2023-04-04 12:48   ` [PATCH v3 14/16] net/failsafe: fix mutex locking David Marchand
2023-04-04 12:48   ` [PATCH v3 15/16] eal/windows: disable lock check on alarm code David Marchand
2023-04-04 16:08     ` Tyler Retzlaff
2023-04-04 21:02     ` Dmitry Kozlyuk
2023-04-04 12:48   ` [PATCH v3 16/16] enable lock check David Marchand
2023-04-11  3:21     ` Sachin Saxena (OSS)
2023-04-23 20:09   ` [PATCH v3 00/16] Enable lock annotations on most libraries and drivers Thomas Monjalon

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