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From: Mina Almasry <almasrymina@google.com>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: "Kaiyuan Zhang" <kaiyuanz@google.com>,
	dri-devel@lists.freedesktop.org,
	"Eric Dumazet" <edumazet@google.com>,
	linux-kselftest@vger.kernel.org, "Shuah Khan" <shuah@kernel.org>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	linux-arch@vger.kernel.org,
	"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
	"Jeroen de Borst" <jeroendb@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Paolo Abeni" <pabeni@redhat.com>,
	linux-media@vger.kernel.org,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	linaro-mm-sig@lists.linaro.org,
	"Shakeel Butt" <shakeelb@google.com>,
	"Willem de Bruijn" <willemb@google.com>,
	netdev@vger.kernel.org, "David Ahern" <dsahern@kernel.org>,
	"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
	linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	"Praveen Kaligineedi" <pkaligineedi@google.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [RFC PATCH v3 04/12] netdev: support binding dma-buf to netdevice
Date: Tue, 7 Nov 2023 13:59:40 -0800	[thread overview]
Message-ID: <CAHS8izPV3isMWyjFnr7bJDDPANg-zm_M=UbHyuhYWv1Viy7fRw@mail.gmail.com> (raw)
In-Reply-To: <1fee982f-1e96-4ae8-ede0-7e57bf84c5f7@huawei.com>

On Mon, Nov 6, 2023 at 11:46 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>
> On 2023/11/6 10:44, Mina Almasry wrote:
> > +
> > +void __netdev_devmem_binding_free(struct netdev_dmabuf_binding *binding)
> > +{
> > +     size_t size, avail;
> > +
> > +     gen_pool_for_each_chunk(binding->chunk_pool,
> > +                             netdev_devmem_free_chunk_owner, NULL);
> > +
> > +     size = gen_pool_size(binding->chunk_pool);
> > +     avail = gen_pool_avail(binding->chunk_pool);
> > +
> > +     if (!WARN(size != avail, "can't destroy genpool. size=%lu, avail=%lu",
> > +               size, avail))
> > +             gen_pool_destroy(binding->chunk_pool);
>
>
> Is there any other place calling the gen_pool_destroy() when the above
> warning is triggered? Do we have a leaking for binding->chunk_pool?
>

gen_pool_destroy BUG_ON() if it's not empty at the time of destroying.
Technically that should never happen, because
__netdev_devmem_binding_free() should only be called when the refcount
hits 0, so all the chunks have been freed back to the gen_pool. But,
just in case, I don't want to crash the server just because I'm
leaking a chunk... this is a bit of defensive programming that is
typically frowned upon, but the behavior of gen_pool is so severe I
think the WARN() + check is warranted here.

> > +
> > +     dma_buf_unmap_attachment(binding->attachment, binding->sgt,
> > +                              DMA_BIDIRECTIONAL);
> > +     dma_buf_detach(binding->dmabuf, binding->attachment);
> > +     dma_buf_put(binding->dmabuf);
> > +     kfree(binding);
> > +}
> > +
>
>


-- 
Thanks,
Mina

WARNING: multiple messages have this Message-ID (diff)
From: Mina Almasry <almasrymina@google.com>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"David Ahern" <dsahern@kernel.org>,
	"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
	"Shuah Khan" <shuah@kernel.org>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Shakeel Butt" <shakeelb@google.com>,
	"Jeroen de Borst" <jeroendb@google.com>,
	"Praveen Kaligineedi" <pkaligineedi@google.com>,
	"Willem de Bruijn" <willemb@google.com>,
	"Kaiyuan Zhang" <kaiyuanz@google.com>
Subject: Re: [RFC PATCH v3 04/12] netdev: support binding dma-buf to netdevice
Date: Tue, 7 Nov 2023 13:59:40 -0800	[thread overview]
Message-ID: <CAHS8izPV3isMWyjFnr7bJDDPANg-zm_M=UbHyuhYWv1Viy7fRw@mail.gmail.com> (raw)
In-Reply-To: <1fee982f-1e96-4ae8-ede0-7e57bf84c5f7@huawei.com>

On Mon, Nov 6, 2023 at 11:46 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>
> On 2023/11/6 10:44, Mina Almasry wrote:
> > +
> > +void __netdev_devmem_binding_free(struct netdev_dmabuf_binding *binding)
> > +{
> > +     size_t size, avail;
> > +
> > +     gen_pool_for_each_chunk(binding->chunk_pool,
> > +                             netdev_devmem_free_chunk_owner, NULL);
> > +
> > +     size = gen_pool_size(binding->chunk_pool);
> > +     avail = gen_pool_avail(binding->chunk_pool);
> > +
> > +     if (!WARN(size != avail, "can't destroy genpool. size=%lu, avail=%lu",
> > +               size, avail))
> > +             gen_pool_destroy(binding->chunk_pool);
>
>
> Is there any other place calling the gen_pool_destroy() when the above
> warning is triggered? Do we have a leaking for binding->chunk_pool?
>

gen_pool_destroy BUG_ON() if it's not empty at the time of destroying.
Technically that should never happen, because
__netdev_devmem_binding_free() should only be called when the refcount
hits 0, so all the chunks have been freed back to the gen_pool. But,
just in case, I don't want to crash the server just because I'm
leaking a chunk... this is a bit of defensive programming that is
typically frowned upon, but the behavior of gen_pool is so severe I
think the WARN() + check is warranted here.

> > +
> > +     dma_buf_unmap_attachment(binding->attachment, binding->sgt,
> > +                              DMA_BIDIRECTIONAL);
> > +     dma_buf_detach(binding->dmabuf, binding->attachment);
> > +     dma_buf_put(binding->dmabuf);
> > +     kfree(binding);
> > +}
> > +
>
>


-- 
Thanks,
Mina

  reply	other threads:[~2023-11-07 21:59 UTC|newest]

Thread overview: 254+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-06  2:43 [RFC PATCH v3 00/12] Device Memory TCP Mina Almasry
2023-11-06  2:43 ` Mina Almasry
2023-11-06  2:44 ` [RFC PATCH v3 01/12] net: page_pool: factor out releasing DMA from releasing the page Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06  2:44 ` [RFC PATCH v3 02/12] net: page_pool: create hooks for custom page providers Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-07  7:44   ` Yunsheng Lin
2023-11-07  7:44     ` Yunsheng Lin
2023-11-09 11:09   ` Paolo Abeni
2023-11-09 11:09     ` Paolo Abeni
2023-11-10 23:19   ` Jakub Kicinski
2023-11-10 23:19     ` Jakub Kicinski
2023-11-13  3:28     ` Mina Almasry
2023-11-13  3:28       ` Mina Almasry
2023-11-13 22:10       ` Jakub Kicinski
2023-11-13 22:10         ` Jakub Kicinski
2023-11-06  2:44 ` [RFC PATCH v3 03/12] net: netdev netlink api to bind dma-buf to a net device Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-10 23:16   ` Jakub Kicinski
2023-11-10 23:16     ` Jakub Kicinski
2023-11-06  2:44 ` [RFC PATCH v3 04/12] netdev: support binding dma-buf to netdevice Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-07  7:46   ` Yunsheng Lin
2023-11-07  7:46     ` Yunsheng Lin
2023-11-07 21:59     ` Mina Almasry [this message]
2023-11-07 21:59       ` Mina Almasry
2023-11-08  3:40       ` Yunsheng Lin
2023-11-08  3:40         ` Yunsheng Lin
2023-11-09  2:22         ` Mina Almasry
2023-11-09  2:22           ` Mina Almasry
2023-11-09  9:29           ` Yunsheng Lin
2023-11-09  9:29             ` Yunsheng Lin
2023-11-08 23:47   ` David Wei
2023-11-08 23:47     ` David Wei
2023-11-09  2:25     ` Mina Almasry
2023-11-09  2:25       ` Mina Almasry
2023-11-09  8:29   ` Paolo Abeni
2023-11-09  8:29     ` Paolo Abeni
2023-11-10  2:59     ` Mina Almasry
2023-11-10  2:59       ` Mina Almasry
2023-11-10  7:38       ` Yunsheng Lin
2023-11-10  7:38         ` Yunsheng Lin
2023-11-10  9:45         ` Mina Almasry
2023-11-10  9:45           ` Mina Almasry
2023-11-10 23:19   ` Jakub Kicinski
2023-11-10 23:19     ` Jakub Kicinski
2023-11-11  2:19     ` Mina Almasry
2023-11-11  2:19       ` Mina Almasry
2023-11-06  2:44 ` [RFC PATCH v3 05/12] netdev: netdevice devmem allocator Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06 23:44   ` David Ahern
2023-11-06 23:44     ` David Ahern
2023-11-07 22:10     ` Mina Almasry
2023-11-07 22:10       ` Mina Almasry
2023-11-07 22:55       ` David Ahern
2023-11-07 22:55         ` David Ahern
2023-11-07 23:03         ` Mina Almasry
2023-11-07 23:03           ` Mina Almasry
2023-11-09  1:15           ` David Wei
2023-11-09  1:15             ` David Wei
2023-11-10 14:26           ` Pavel Begunkov
2023-11-10 14:26             ` Pavel Begunkov
2023-11-11 17:19             ` David Ahern
2023-11-11 17:19               ` David Ahern
2023-11-14 16:09               ` Pavel Begunkov
2023-11-14 16:09                 ` Pavel Begunkov
2023-11-09  1:00         ` David Wei
2023-11-09  1:00           ` David Wei
2023-11-08  3:48       ` Yunsheng Lin
2023-11-08  3:48         ` Yunsheng Lin
2023-11-09  1:41         ` Mina Almasry
2023-11-09  1:41           ` Mina Almasry
2023-11-07  7:45   ` Yunsheng Lin
2023-11-07  7:45     ` Yunsheng Lin
2023-11-09  8:44   ` Paolo Abeni
2023-11-09  8:44     ` Paolo Abeni
2023-11-06  2:44 ` [RFC PATCH v3 06/12] memory-provider: dmabuf devmem memory provider Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06 21:02   ` Stanislav Fomichev
2023-11-06 21:02     ` Stanislav Fomichev
2023-11-06 23:49   ` David Ahern
2023-11-06 23:49     ` David Ahern
2023-11-08  0:02     ` Mina Almasry
2023-11-08  0:02       ` Mina Almasry
2023-11-08  0:10       ` David Ahern
2023-11-08  0:10         ` David Ahern
2023-11-10 23:16   ` Jakub Kicinski
2023-11-10 23:16     ` Jakub Kicinski
2023-11-13  4:54     ` Mina Almasry
2023-11-13  4:54       ` Mina Almasry
2023-11-06  2:44 ` [RFC PATCH v3 07/12] page-pool: device memory support Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-07  8:00   ` Yunsheng Lin
2023-11-07  8:00     ` Yunsheng Lin
2023-11-07 21:56     ` Mina Almasry
2023-11-07 21:56       ` Mina Almasry
2023-11-08 10:56       ` Yunsheng Lin
2023-11-08 10:56         ` Yunsheng Lin
2023-11-09  3:20         ` Mina Almasry
2023-11-09  3:20           ` Mina Almasry
2023-11-09  9:30           ` Yunsheng Lin
2023-11-09  9:30             ` Yunsheng Lin
2023-11-09 12:20             ` Mina Almasry
2023-11-09 12:20               ` Mina Almasry
2023-11-09 13:23               ` Yunsheng Lin
2023-11-09 13:23                 ` Yunsheng Lin
2023-11-09 14:23           ` Christian König
2023-11-09  9:01   ` Paolo Abeni
2023-11-09  9:01     ` Paolo Abeni
2023-11-06  2:44 ` [RFC PATCH v3 08/12] net: support non paged skb frags Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-07  9:00   ` Yunsheng Lin
2023-11-07  9:00     ` Yunsheng Lin
2023-11-07 21:19     ` Mina Almasry
2023-11-07 21:19       ` Mina Almasry
2023-11-08 11:25       ` Yunsheng Lin
2023-11-08 11:25         ` Yunsheng Lin
2023-11-09  9:14   ` Paolo Abeni
2023-11-09  9:14     ` Paolo Abeni
2023-11-10  4:06     ` Mina Almasry
2023-11-10  4:06       ` Mina Almasry
2023-11-10 23:19   ` Jakub Kicinski
2023-11-10 23:19     ` Jakub Kicinski
2023-11-13  6:05     ` Mina Almasry
2023-11-13  6:05       ` Mina Almasry
2023-11-13 22:17       ` Jakub Kicinski
2023-11-13 22:17         ` Jakub Kicinski
2023-11-06  2:44 ` [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06 18:47   ` Stanislav Fomichev
2023-11-06 18:47     ` Stanislav Fomichev
2023-11-06 19:34     ` David Ahern
2023-11-06 19:34       ` David Ahern
2023-11-06 20:31       ` Mina Almasry
2023-11-06 20:31         ` Mina Almasry
2023-11-06 21:59         ` Stanislav Fomichev
2023-11-06 21:59           ` Stanislav Fomichev
2023-11-06 22:18           ` Mina Almasry
2023-11-06 22:18             ` Mina Almasry
2023-11-06 22:59             ` Stanislav Fomichev
2023-11-06 22:59               ` Stanislav Fomichev
2023-11-06 23:14               ` Kaiyuan Zhang
2023-11-06 23:27               ` Mina Almasry
2023-11-06 23:27                 ` Mina Almasry
2023-11-06 23:55                 ` Stanislav Fomichev
2023-11-06 23:55                   ` Stanislav Fomichev
2023-11-07  0:07                   ` Willem de Bruijn
2023-11-07  0:07                     ` Willem de Bruijn
2023-11-07  0:14                     ` Stanislav Fomichev
2023-11-07  0:14                       ` Stanislav Fomichev
2023-11-07  0:59                       ` Stanislav Fomichev
2023-11-07  0:59                         ` Stanislav Fomichev
2023-11-07  2:23                         ` Willem de Bruijn
2023-11-07  2:23                           ` Willem de Bruijn
2023-11-07 17:44                           ` Stanislav Fomichev
2023-11-07 17:44                             ` Stanislav Fomichev
2023-11-07 17:57                             ` Willem de Bruijn
2023-11-07 17:57                               ` Willem de Bruijn
2023-11-07 18:14                               ` Stanislav Fomichev
2023-11-07 18:14                                 ` Stanislav Fomichev
2023-11-07  0:20                     ` Mina Almasry
2023-11-07  0:20                       ` Mina Almasry
2023-11-07  1:06                       ` Stanislav Fomichev
2023-11-07  1:06                         ` Stanislav Fomichev
2023-11-07 19:53                         ` Mina Almasry
2023-11-07 19:53                           ` Mina Almasry
2023-11-07 21:05                           ` Stanislav Fomichev
2023-11-07 21:05                             ` Stanislav Fomichev
2023-11-07 21:17                             ` Eric Dumazet
2023-11-07 21:17                               ` Eric Dumazet
2023-11-07 22:23                               ` Stanislav Fomichev
2023-11-07 22:23                                 ` Stanislav Fomichev
2023-11-10 23:17                                 ` Jakub Kicinski
2023-11-10 23:17                                   ` Jakub Kicinski
2023-11-10 23:19                           ` Jakub Kicinski
2023-11-10 23:19                             ` Jakub Kicinski
2023-11-07  1:09                       ` David Ahern
2023-11-07  1:09                         ` David Ahern
2023-11-06 23:37             ` David Ahern
2023-11-06 23:37               ` David Ahern
2023-11-07  0:03               ` Mina Almasry
2023-11-07  0:03                 ` Mina Almasry
2023-11-06 20:56   ` Stanislav Fomichev
2023-11-06 20:56     ` Stanislav Fomichev
2023-11-07  0:16   ` David Ahern
2023-11-07  0:16     ` David Ahern
2023-11-07  0:23     ` Mina Almasry
2023-11-07  0:23       ` Mina Almasry
2023-11-08 14:43   ` David Laight
2023-11-08 14:43     ` David Laight
2023-11-06  2:44 ` [RFC PATCH v3 10/12] tcp: RX path for devmem TCP Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06 18:44   ` Stanislav Fomichev
2023-11-06 18:44     ` Stanislav Fomichev
2023-11-06 19:29     ` Mina Almasry
2023-11-06 19:29       ` Mina Almasry
2023-11-06 21:14       ` Willem de Bruijn
2023-11-06 21:14         ` Willem de Bruijn
2023-11-06 22:34         ` Stanislav Fomichev
2023-11-06 22:34           ` Stanislav Fomichev
2023-11-06 22:55           ` Willem de Bruijn
2023-11-06 22:55             ` Willem de Bruijn
2023-11-06 23:32             ` Stanislav Fomichev
2023-11-06 23:32               ` Stanislav Fomichev
2023-11-06 23:55               ` David Ahern
2023-11-06 23:55                 ` David Ahern
2023-11-07  0:02                 ` Willem de Bruijn
2023-11-07  0:02                   ` Willem de Bruijn
2023-11-07 23:55                   ` Mina Almasry
2023-11-07 23:55                     ` Mina Almasry
2023-11-08  0:01                     ` David Ahern
2023-11-08  0:01                       ` David Ahern
2023-11-09  2:39                       ` Mina Almasry
2023-11-09  2:39                         ` Mina Almasry
2023-11-09 16:07                         ` Edward Cree
2023-11-09 16:07                           ` Edward Cree
2023-12-08 20:12                           ` Pavel Begunkov
2023-12-08 20:12                             ` Pavel Begunkov
2023-11-09 11:05             ` Paolo Abeni
2023-11-09 11:05               ` Paolo Abeni
2023-11-10 23:16               ` Jakub Kicinski
2023-11-10 23:16                 ` Jakub Kicinski
2023-12-08 20:28             ` Pavel Begunkov
2023-12-08 20:28               ` Pavel Begunkov
2023-12-08 20:09           ` Pavel Begunkov
2023-12-08 20:09             ` Pavel Begunkov
2023-11-06 21:17       ` Stanislav Fomichev
2023-11-06 21:17         ` Stanislav Fomichev
2023-11-08 15:36         ` Edward Cree
2023-11-08 15:36           ` Edward Cree
2023-11-09 10:52   ` Paolo Abeni
2023-11-09 10:52     ` Paolo Abeni
2023-11-10 23:19   ` Jakub Kicinski
2023-11-10 23:19     ` Jakub Kicinski
2023-11-06  2:44 ` [RFC PATCH v3 11/12] net: add SO_DEVMEM_DONTNEED setsockopt to release RX pages Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-06  2:44 ` [RFC PATCH v3 12/12] selftests: add ncdevmem, netcat for devmem TCP Mina Almasry
2023-11-06  2:44   ` Mina Almasry
2023-11-09 11:03   ` Paolo Abeni
2023-11-09 11:03     ` Paolo Abeni
2023-11-10 23:13   ` Jakub Kicinski
2023-11-10 23:13     ` Jakub Kicinski
2023-11-11  2:27     ` Mina Almasry
2023-11-11  2:27       ` Mina Almasry
2023-11-11  2:35       ` Jakub Kicinski
2023-11-11  2:35         ` Jakub Kicinski
2023-11-13  4:08         ` Mina Almasry
2023-11-13  4:08           ` Mina Almasry
2023-11-13 22:20           ` Jakub Kicinski
2023-11-13 22:20             ` Jakub Kicinski
2023-11-10 23:17   ` Jakub Kicinski
2023-11-10 23:17     ` Jakub Kicinski
2023-11-07 15:18 ` [RFC PATCH v3 00/12] Device Memory TCP David Ahern
2023-11-07 15:18   ` David Ahern

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