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Commit a74e9106 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Cc: Mike Waychison <mikew@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b139ba4e

net/socket.c

+16 −21
Original line number Diff line number Diff line
@@ -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 */

	if (msg_sys->msg_iovlen > UIO_FASTIOV) {

		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);

		iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),

			      GFP_KERNEL);

		if (!iov)

			goto out;

	}
@@ -2005,7 +2002,7 @@ static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg, 
		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;



	if (msg_sys->msg_iovlen > UIO_FASTIOV) {

		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);

		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;

}