From 0cad74c5636512031a5877de13f09b03227f1106 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 28 May 2020 07:12:16 +0200 Subject: [PATCH] net: add sock_set_rcvbuf Add a helper to directly set the SO_RCVBUFFORCE sockopt from kernel space without going through a fake uaccess. Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller --- fs/dlm/lowcomms.c | 7 +----- include/net/sock.h | 1 + net/core/sock.c | 59 +++++++++++++++++++++++++--------------------- 3 files changed, 34 insertions(+), 33 deletions(-) diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index b6e6dba281547..2822a430a2b49 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -1180,7 +1180,6 @@ static int sctp_listen_for_all(void) struct socket *sock = NULL; int result = -EINVAL; struct connection *con = nodeid2con(0, GFP_NOFS); - int bufsize = NEEDED_RMEM; int one = 1; if (!con) @@ -1195,11 +1194,7 @@ static int sctp_listen_for_all(void) goto out; } - result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE, - (char *)&bufsize, sizeof(bufsize)); - if (result) - log_print("Error increasing buffer space on socket %d", result); - + sock_set_rcvbuf(sock->sk, NEEDED_RMEM); result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one, sizeof(one)); if (result < 0) diff --git a/include/net/sock.h b/include/net/sock.h index dc08c176238fd..c997289aabbf9 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2693,6 +2693,7 @@ void sock_enable_timestamps(struct sock *sk); void sock_no_linger(struct sock *sk); void sock_set_keepalive(struct sock *sk); void sock_set_priority(struct sock *sk, u32 priority); +void sock_set_rcvbuf(struct sock *sk, int val); void sock_set_reuseaddr(struct sock *sk); void sock_set_sndtimeo(struct sock *sk, s64 secs); diff --git a/net/core/sock.c b/net/core/sock.c index 728f5fb156a0c..3c6ebf952e9ad 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -789,6 +789,35 @@ void sock_set_keepalive(struct sock *sk) } EXPORT_SYMBOL(sock_set_keepalive); +static void __sock_set_rcvbuf(struct sock *sk, int val) +{ + /* Ensure val * 2 fits into an int, to prevent max_t() from treating it + * as a negative value. + */ + val = min_t(int, val, INT_MAX / 2); + sk->sk_userlocks |= SOCK_RCVBUF_LOCK; + + /* We double it on the way in to account for "struct sk_buff" etc. + * overhead. Applications assume that the SO_RCVBUF setting they make + * will allow that much actual data to be received on that socket. + * + * Applications are unaware that "struct sk_buff" and other overheads + * allocate from the receive buffer during socket buffer allocation. + * + * And after considering the possible alternatives, returning the value + * we actually used in getsockopt is the most desirable behavior. + */ + WRITE_ONCE(sk->sk_rcvbuf, max_t(int, val * 2, SOCK_MIN_RCVBUF)); +} + +void sock_set_rcvbuf(struct sock *sk, int val) +{ + lock_sock(sk); + __sock_set_rcvbuf(sk, val); + release_sock(sk); +} +EXPORT_SYMBOL(sock_set_rcvbuf); + /* * This is meant for all protocols to use and covers goings on * at the socket level. Everything here is generic. @@ -885,30 +914,7 @@ set_sndbuf: * play 'guess the biggest size' games. RCVBUF/SNDBUF * are treated in BSD as hints */ - val = min_t(u32, val, sysctl_rmem_max); -set_rcvbuf: - /* Ensure val * 2 fits into an int, to prevent max_t() - * from treating it as a negative value. - */ - val = min_t(int, val, INT_MAX / 2); - sk->sk_userlocks |= SOCK_RCVBUF_LOCK; - /* - * We double it on the way in to account for - * "struct sk_buff" etc. overhead. Applications - * assume that the SO_RCVBUF setting they make will - * allow that much actual data to be received on that - * socket. - * - * Applications are unaware that "struct sk_buff" and - * other overheads allocate from the receive buffer - * during socket buffer allocation. - * - * And after considering the possible alternatives, - * returning the value we actually used in getsockopt - * is the most desirable behavior. - */ - WRITE_ONCE(sk->sk_rcvbuf, - max_t(int, val * 2, SOCK_MIN_RCVBUF)); + __sock_set_rcvbuf(sk, min_t(u32, val, sysctl_rmem_max)); break; case SO_RCVBUFFORCE: @@ -920,9 +926,8 @@ set_rcvbuf: /* No negative values (to prevent underflow, as val will be * multiplied by 2). */ - if (val < 0) - val = 0; - goto set_rcvbuf; + __sock_set_rcvbuf(sk, max(val, 0)); + break; case SO_KEEPALIVE: if (sk->sk_prot->keepalive) -- 2.39.5