Re: [net-next v1 14/16] net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags
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From: Simon Horman <horms@kernel.org>
Date: 2023-12-12 19:08:24
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bpf, dri-devel, linux-arch, linux-doc, linux-kselftest, linux-media, lkml
On Thu, Dec 07, 2023 at 04:52:45PM -0800, Mina Almasry wrote:
Add an interface for the user to notify the kernel that it is done reading the devmem dmabuf frags returned as cmsg. The kernel will drop the reference on the frags to make them available for re-use. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <redacted> Signed-off-by: Mina Almasry <redacted>
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diff --git a/net/core/sock.c b/net/core/sock.c index fef349dd72fa..521bdc4ff260 100644 --- a/net/core/sock.c +++ b/net/core/sock.c@@ -1051,6 +1051,41 @@ static int sock_reserve_memory(struct sock *sk, int bytes) return 0; } +static noinline_for_stack int +sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + struct dmabuf_token tokens[128];
Hi Mina, I am guessing it is mostly due to the line above, but on x86 32bit builds I see: warning: the frame size of 1048 bytes is larger than 1024 bytes [-Wframe-larger-than
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+ unsigned int num_tokens, i, j; + int ret; + + if (sk->sk_type != SOCK_STREAM || sk->sk_protocol != IPPROTO_TCP) + return -EBADF; + + if (optlen % sizeof(struct dmabuf_token) || optlen > sizeof(tokens)) + return -EINVAL; + + num_tokens = optlen / sizeof(struct dmabuf_token); + if (copy_from_sockptr(tokens, optval, optlen)) + return -EFAULT; + + ret = 0; + for (i = 0; i < num_tokens; i++) { + for (j = 0; j < tokens[i].token_count; j++) { + struct page *page = xa_erase(&sk->sk_user_pages, + tokens[i].token_start + j); + + if (page) { + if (WARN_ON_ONCE(!napi_pp_put_page(page, + false))) + page_pool_page_put_many(page, 1); + ret++; + } + } + } + + return ret; +} + void sockopt_lock_sock(struct sock *sk) { /* When current->bpf_ctx is set, the setsockopt is called from
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