path: root/net/compat.c
diff options
authorArnaldo Carvalho de Melo <acme@redhat.com>2009-10-12 23:40:10 -0700
committerDavid S. Miller <davem@davemloft.net>2009-10-12 23:40:10 -0700
commita2e2725541fad72416326798c2d7fa4dafb7d337 (patch)
tree6174be11da607e83eb8efb3775114ad4d6e0ca3a /net/compat.c
parentc05e85a06e376f6b6d59e71e5333d707e956d78b (diff)
net: Introduce recvmmsg socket syscall
Meaning receive multiple messages, reducing the number of syscalls and net stack entry/exit operations. Next patches will introduce mechanisms where protocols that want to optimize this operation will provide an unlocked_recvmsg operation. This takes into account comments made by: . Paul Moore: sock_recvmsg is called only for the first datagram, sock_recvmsg_nosec is used for the rest. . Caitlin Bestler: recvmmsg now has a struct timespec timeout, that works in the same fashion as the ppoll one. If the underlying protocol returns a datagram with MSG_OOB set, this will make recvmmsg return right away with as many datagrams (+ the OOB one) it has received so far. . RĂ©mi Denis-Courmont & Steven Whitehouse: If we receive N < vlen datagrams and then recvmsg returns an error, recvmmsg will return the successfully received datagrams, store the error and return it in the next call. This paves the way for a subsequent optimization, sk_prot->unlocked_recvmsg, where we will be able to acquire the lock only at batch start and end, not at every underlying recvmsg call. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/compat.c')
1 files changed, 30 insertions, 3 deletions
diff --git a/net/compat.c b/net/compat.c
index a407c3addbae..e13f5256fd20 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -727,10 +727,10 @@ EXPORT_SYMBOL(compat_mc_getsockopt);
/* Argument list sizes for compat_sys_socketcall */
#define AL(x) ((x) * sizeof(u32))
-static unsigned char nas[19]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
+static unsigned char nas[20]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
- AL(4)};
+ AL(4),AL(5)};
#undef AL
asmlinkage long compat_sys_sendmsg(int fd, struct compat_msghdr __user *msg, unsigned flags)
@@ -755,13 +755,36 @@ asmlinkage long compat_sys_recvfrom(int fd, void __user *buf, size_t len,
return sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr, addrlen);
+asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
+ unsigned vlen, unsigned int flags,
+ struct timespec __user *timeout)
+ int datagrams;
+ struct timespec ktspec;
+ struct compat_timespec __user *utspec =
+ (struct compat_timespec __user *)timeout;
+ if (get_user(ktspec.tv_sec, &utspec->tv_sec) ||
+ get_user(ktspec.tv_nsec, &utspec->tv_nsec))
+ return -EFAULT;
+ datagrams = __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
+ flags | MSG_CMSG_COMPAT, &ktspec);
+ if (datagrams > 0 &&
+ (put_user(ktspec.tv_sec, &utspec->tv_sec) ||
+ put_user(ktspec.tv_nsec, &utspec->tv_nsec)))
+ datagrams = -EFAULT;
+ return datagrams;
asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
int ret;
u32 a[6];
u32 a0, a1;
- if (call < SYS_SOCKET || call > SYS_ACCEPT4)
+ if (call < SYS_SOCKET || call > SYS_RECVMMSG)
return -EINVAL;
if (copy_from_user(a, args, nas[call]))
return -EFAULT;
@@ -823,6 +846,10 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
ret = compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
+ ret = compat_sys_recvmmsg(a0, compat_ptr(a1), a[2], a[3],
+ compat_ptr(a[4]));
+ break;
ret = sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);

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