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Wed, 07 Jan 2026 16:58:40 -0800 (PST) From: Bobby Eshleman Date: Wed, 07 Jan 2026 16:57:36 -0800 Subject: [PATCH net-next v8 2/5] net: devmem: refactor sock_devmem_dontneed for autorelease split Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260107-scratch-bobbyeshleman-devmem-tcp-token-upstream-v8-2-92c968631496@meta.com> References: <20260107-scratch-bobbyeshleman-devmem-tcp-token-upstream-v8-0-92c968631496@meta.com> In-Reply-To: <20260107-scratch-bobbyeshleman-devmem-tcp-token-upstream-v8-0-92c968631496@meta.com> To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , Neal Cardwell , David Ahern , Arnd Bergmann , Jonathan Corbet , Andrew Lunn , Shuah Khan , Donald Hunter , Mina Almasry Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Stanislav Fomichev , asml.silence@gmail.com, matttbe@kernel.org, skhawaja@google.com, Bobby Eshleman X-Mailer: b4 0.14.3 From: Bobby Eshleman Refactor sock_devmem_dontneed() in preparation for supporting both autorelease and manual token release modes. Split the function into two parts: - sock_devmem_dontneed(): handles input validation, token allocation, and copying from userspace - sock_devmem_dontneed_autorelease(): performs the actual token release via xarray lookup and page pool put This separation allows a future commit to add a parallel sock_devmem_dontneed_manual_release() function that uses a different token tracking mechanism (per-niov reference counting) without duplicating the input validation logic. The refactoring is purely mechanical with no functional change. Only intended to minimize the noise in subsequent patches. Reviewed-by: Mina Almasry Signed-off-by: Bobby Eshleman --- net/core/sock.c | 52 ++++++++++++++++++++++++++++++++-------------------- 1 file changed, 32 insertions(+), 20 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 45c98bf524b2..a5932719b191 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1082,30 +1082,13 @@ static int sock_reserve_memory(struct sock *sk, int= bytes) #define MAX_DONTNEED_FRAGS 1024 =20 static noinline_for_stack int -sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optle= n) +sock_devmem_dontneed_autorelease(struct sock *sk, struct dmabuf_token *tok= ens, + unsigned int num_tokens) { - unsigned int num_tokens, i, j, k, netmem_num =3D 0; - struct dmabuf_token *tokens; + unsigned int i, j, k, netmem_num =3D 0; int ret =3D 0, num_frags =3D 0; netmem_ref netmems[16]; =20 - if (!sk_is_tcp(sk)) - return -EBADF; - - if (optlen % sizeof(*tokens) || - optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS) - return -EINVAL; - - num_tokens =3D optlen / sizeof(*tokens); - tokens =3D kvmalloc_array(num_tokens, sizeof(*tokens), GFP_KERNEL); - if (!tokens) - return -ENOMEM; - - if (copy_from_sockptr(tokens, optval, optlen)) { - kvfree(tokens); - return -EFAULT; - } - xa_lock_bh(&sk->sk_user_frags); for (i =3D 0; i < num_tokens; i++) { for (j =3D 0; j < tokens[i].token_count; j++) { @@ -1135,6 +1118,35 @@ sock_devmem_dontneed(struct sock *sk, sockptr_t optv= al, unsigned int optlen) for (k =3D 0; k < netmem_num; k++) WARN_ON_ONCE(!napi_pp_put_page(netmems[k])); =20 + return ret; +} + +static noinline_for_stack int +sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optle= n) +{ + struct dmabuf_token *tokens; + unsigned int num_tokens; + int ret; + + if (!sk_is_tcp(sk)) + return -EBADF; + + if (optlen % sizeof(*tokens) || + optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS) + return -EINVAL; + + num_tokens =3D optlen / sizeof(*tokens); + tokens =3D kvmalloc_array(num_tokens, sizeof(*tokens), GFP_KERNEL); + if (!tokens) + return -ENOMEM; + + if (copy_from_sockptr(tokens, optval, optlen)) { + kvfree(tokens); + return -EFAULT; + } + + ret =3D sock_devmem_dontneed_autorelease(sk, tokens, num_tokens); + kvfree(tokens); return ret; } --=20 2.47.3