net: change big iov allocations

iov of more than 8 entries are allocated in sendmsg()/recvmsg() through
sock_kmalloc()

As these allocations are temporary only and small enough, it makes sense
to use plain kmalloc() and avoid sk_omem_alloc atomic overhead.

Slightly changed fast path to be even faster.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mike Waychison <mikew@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/socket.c b/net/socket.c
index e345109..d3aaa4f 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -1908,7 +1908,7 @@ static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
            __attribute__ ((aligned(sizeof(__kernel_size_t))));
        /* 20 is size of ipv6_pktinfo */
        unsigned char *ctl_buf = ctl;
-       int err, ctl_len, iov_size, total_len;
+       int err, ctl_len, total_len;
 
        err = -EFAULT;
        if (MSG_CMSG_COMPAT & flags) {
@@ -1917,16 +1917,13 @@ static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
        } else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr)))
                return -EFAULT;
 
-       /* do not move before msg_sys is valid */
-       err = -EMSGSIZE;
-       if (msg_sys->msg_iovlen > UIO_MAXIOV)
-               goto out;
-
-       /* Check whether to allocate the iovec area */
-       err = -ENOMEM;
-       iov_size = msg_sys->msg_iovlen * sizeof(struct iovec);
        if (msg_sys->msg_iovlen > UIO_FASTIOV) {
-               iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
+               err = -EMSGSIZE;
+               if (msg_sys->msg_iovlen > UIO_MAXIOV)
+                       goto out;
+               err = -ENOMEM;
+               iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
+                             GFP_KERNEL);
                if (!iov)
                        goto out;
        }
@@ -2005,7 +2002,7 @@ out_freectl:
                sock_kfree_s(sock->sk, ctl_buf, ctl_len);
 out_freeiov:
        if (iov != iovstack)
-               sock_kfree_s(sock->sk, iov, iov_size);
+               kfree(iov);
 out:
        return err;
 }
@@ -2103,7 +2100,7 @@ static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
        struct iovec iovstack[UIO_FASTIOV];
        struct iovec *iov = iovstack;
        unsigned long cmsg_ptr;
-       int err, iov_size, total_len, len;
+       int err, total_len, len;
 
        /* kernel mode address */
        struct sockaddr_storage addr;
@@ -2118,15 +2115,13 @@ static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
        } else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr)))
                return -EFAULT;
 
-       err = -EMSGSIZE;
-       if (msg_sys->msg_iovlen > UIO_MAXIOV)
-               goto out;
-
-       /* Check whether to allocate the iovec area */
-       err = -ENOMEM;
-       iov_size = msg_sys->msg_iovlen * sizeof(struct iovec);
        if (msg_sys->msg_iovlen > UIO_FASTIOV) {
-               iov = sock_kmalloc(sock->sk, iov_size, GFP_KERNEL);
+               err = -EMSGSIZE;
+               if (msg_sys->msg_iovlen > UIO_MAXIOV)
+                       goto out;
+               err = -ENOMEM;
+               iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
+                             GFP_KERNEL);
                if (!iov)
                        goto out;
        }
@@ -2180,7 +2175,7 @@ static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
 
 out_freeiov:
        if (iov != iovstack)
-               sock_kfree_s(sock->sk, iov, iov_size);
+               kfree(iov);
 out:
        return err;
 }