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.

. Rémi 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>

18 files changed, 23 insertions, 5 deletions

diff --git a/arch/alpha/kernel/systbls.S b/arch/alpha/kernel/systbls.S
index 95c9aef1c106..cda6b8b3d573 100644
--- a/arch/alpha/kernel/systbls.S
+++ b/arch/alpha/kernel/systbls.S
@@ -497,6 +497,7 @@ sys_call_table:
         .quad sys_signalfd
         .quad sys_ni_syscall
         .quad sys_eventfd
+        .quad sys_recvmmsg
 
         .size sys_call_table, . - sys_call_table
         .type sys_call_table, @object
diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index fafce1b5c69f..f58c1156e779 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -374,6 +374,7 @@
                 CALL(sys_pwritev)
                 CALL(sys_rt_tgsigqueueinfo)
                 CALL(sys_perf_event_open)
+/* 365 */       CALL(sys_recvmmsg)
 #ifndef syscalls_counted
 .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
 #define syscalls_counted
diff --git a/arch/avr32/kernel/syscall_table.S b/arch/avr32/kernel/syscall_table.S
index 7ee0057613b3..e76bad16b0f0 100644
--- a/arch/avr32/kernel/syscall_table.S
+++ b/arch/avr32/kernel/syscall_table.S
@@ -295,4 +295,5 @@ sys_call_table:
         .long   sys_signalfd
         .long   sys_ni_syscall          /* 280, was sys_timerfd */
         .long   sys_eventfd
+        .long   sys_recvmmsg
         .long   sys_ni_syscall          /* r8 is saturated at nr_syscalls */
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 1e7cac23e25f..48692724b74c 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -1621,6 +1621,7 @@ ENTRY(_sys_call_table)
         .long _sys_pwritev
         .long _sys_rt_tgsigqueueinfo
         .long _sys_perf_event_open
+        .long _sys_recvmmsg             /* 370 */
 
         .rept NR_syscalls-(.-_sys_call_table)/4
         .long _sys_ni_syscall
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index d0e7d37017b4..d75b872ca4dc 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1806,6 +1806,7 @@ sys_call_table:
         data8 sys_preadv
         data8 sys_pwritev                       // 1320
         data8 sys_rt_tgsigqueueinfo
+        data8 sys_recvmmsg
 
         .org sys_call_table + 8*NR_syscalls     // guard against failures to increase NR_syscalls
 #endif /* __IA64_ASM_PARAVIRTUALIZED_NATIVE */
diff --git a/arch/microblaze/kernel/syscall_table.S b/arch/microblaze/kernel/syscall_table.S
index ecec19155135..c1ab1dc10898 100644
--- a/arch/microblaze/kernel/syscall_table.S
+++ b/arch/microblaze/kernel/syscall_table.S
@@ -371,3 +371,4 @@ ENTRY(sys_call_table)
         .long sys_ni_syscall
         .long sys_rt_tgsigqueueinfo     /* 365 */
         .long sys_perf_event_open
+        .long sys_recvmmsg
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index fd2a9bb620d6..17202bbe843f 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -583,6 +583,7 @@ einval:	li	v0, -ENOSYS
         sys     sys_rt_tgsigqueueinfo   4
         sys     sys_perf_event_open     5
         sys     sys_accept4             4
+        sys     sys_recvmmsg            5
         .endm
 
         /* We pre-compute the number of _instruction_ bytes needed to
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 18bf7f32c5e4..a8a6c596eb04 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -420,4 +420,5 @@ sys_call_table:
         PTR     sys_rt_tgsigqueueinfo
         PTR     sys_perf_event_open
         PTR     sys_accept4
+        PTR     sys_recvmmsg
         .size   sys_call_table,.-sys_call_table
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index 6ebc07976694..5154e64f7cfe 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -418,4 +418,5 @@ EXPORT(sysn32_call_table)
         PTR     compat_sys_rt_tgsigqueueinfo    /* 5295 */
         PTR     sys_perf_event_open
         PTR     sys_accept4
+        PTR     compat_sys_recvmmsg
         .size   sysn32_call_table,.-sysn32_call_table
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 9bbf9775e0bd..d0eff53d7cb9 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -538,4 +538,5 @@ sys_call_table:
         PTR     compat_sys_rt_tgsigqueueinfo
         PTR     sys_perf_event_open
         PTR     sys_accept4
+        PTR     compat_sys_recvmmsg
         .size   sys_call_table,.-sys_call_table
diff --git a/arch/sh/kernel/syscalls_64.S b/arch/sh/kernel/syscalls_64.S
index 5bfde6c77498..07d2aaea9ae8 100644
--- a/arch/sh/kernel/syscalls_64.S
+++ b/arch/sh/kernel/syscalls_64.S
@@ -391,3 +391,4 @@ sys_call_table:
         .long sys_pwritev
         .long sys_rt_tgsigqueueinfo
         .long sys_perf_event_open
+        .long sys_recvmmsg              /* 365 */
diff --git a/arch/sparc/kernel/systbls_32.S b/arch/sparc/kernel/systbls_32.S
index 0f1658d37490..ceb1530f8aa6 100644
--- a/arch/sparc/kernel/systbls_32.S
+++ b/arch/sparc/kernel/systbls_32.S
@@ -82,5 +82,5 @@ sys_call_table:
 /*310*/ .long sys_utimensat, sys_signalfd, sys_timerfd_create, sys_eventfd, sys_fallocate
 /*315*/ .long sys_timerfd_settime, sys_timerfd_gettime, sys_signalfd4, sys_eventfd2, sys_epoll_create1
 /*320*/ .long sys_dup3, sys_pipe2, sys_inotify_init1, sys_accept4, sys_preadv
-/*325*/ .long sys_pwritev, sys_rt_tgsigqueueinfo, sys_perf_event_open
+/*325*/ .long sys_pwritev, sys_rt_tgsigqueueinfo, sys_perf_event_open, sys_recvmmsg
 
diff --git a/arch/sparc/kernel/systbls_64.S b/arch/sparc/kernel/systbls_64.S
index 009825f6e73c..f37bef747e60 100644
--- a/arch/sparc/kernel/systbls_64.S
+++ b/arch/sparc/kernel/systbls_64.S
@@ -83,7 +83,7 @@ sys_call_table32:
 /*310*/ .word compat_sys_utimensat, compat_sys_signalfd, sys_timerfd_create, sys_eventfd, compat_sys_fallocate
         .word compat_sys_timerfd_settime, compat_sys_timerfd_gettime, compat_sys_signalfd4, sys_eventfd2, sys_epoll_create1
 /*320*/ .word sys_dup3, sys_pipe2, sys_inotify_init1, sys_accept4, compat_sys_preadv
-        .word compat_sys_pwritev, compat_sys_rt_tgsigqueueinfo, sys_perf_event_open
+        .word compat_sys_pwritev, compat_sys_rt_tgsigqueueinfo, sys_perf_event_open, compat_sys_recvmmsg
 
 #endif /* CONFIG_COMPAT */
 
@@ -158,4 +158,4 @@ sys_call_table:
 /*310*/ .word sys_utimensat, sys_signalfd, sys_timerfd_create, sys_eventfd, sys_fallocate
         .word sys_timerfd_settime, sys_timerfd_gettime, sys_signalfd4, sys_eventfd2, sys_epoll_create1
 /*320*/ .word sys_dup3, sys_pipe2, sys_inotify_init1, sys_accept4, sys_preadv
-        .word sys_pwritev, sys_rt_tgsigqueueinfo, sys_perf_event_open
+        .word sys_pwritev, sys_rt_tgsigqueueinfo, sys_perf_event_open, sys_recvmmsg
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 74619c4f9fda..11a6c79d5f46 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -832,4 +832,5 @@ ia32_sys_call_table:
         .quad compat_sys_pwritev
         .quad compat_sys_rt_tgsigqueueinfo      /* 335 */
         .quad sys_perf_event_open
+        .quad compat_sys_recvmmsg
 ia32_syscall_end:
diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
index 6fb3c209a7e3..3baf379fa840 100644
--- a/arch/x86/include/asm/unistd_32.h
+++ b/arch/x86/include/asm/unistd_32.h
@@ -342,10 +342,11 @@
 #define __NR_pwritev            334
 #define __NR_rt_tgsigqueueinfo  335
 #define __NR_perf_event_open    336
+#define __NR_recvmmsg           337
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 337
+#define NR_syscalls 338
 
 #define __ARCH_WANT_IPC_PARSE_VERSION
 #define __ARCH_WANT_OLD_READDIR
diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
index 8d3ad0adbc68..4843f7ba754a 100644
--- a/arch/x86/include/asm/unistd_64.h
+++ b/arch/x86/include/asm/unistd_64.h
@@ -661,6 +661,8 @@ __SYSCALL(__NR_pwritev, sys_pwritev)
 __SYSCALL(__NR_rt_tgsigqueueinfo, sys_rt_tgsigqueueinfo)
 #define __NR_perf_event_open                    298
 __SYSCALL(__NR_perf_event_open, sys_perf_event_open)
+#define __NR_recvmmsg                           299
+__SYSCALL(__NR_recvmmsg, sys_recvmmsg)
 
 #ifndef __NO_STUBS
 #define __ARCH_WANT_OLD_READDIR
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index 0157cd26d7cc..70c2125d55b9 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -336,3 +336,4 @@ ENTRY(sys_call_table)
         .long sys_pwritev
         .long sys_rt_tgsigqueueinfo     /* 335 */
         .long sys_perf_event_open
+        .long sys_recvmmsg
diff --git a/arch/xtensa/include/asm/unistd.h b/arch/xtensa/include/asm/unistd.h
index c092c8fbb2cf..4e55dc763021 100644
--- a/arch/xtensa/include/asm/unistd.h
+++ b/arch/xtensa/include/asm/unistd.h
@@ -681,8 +681,10 @@ __SYSCALL(304, sys_signalfd, 3)
 __SYSCALL(305, sys_ni_syscall, 0)
 #define __NR_eventfd                            306
 __SYSCALL(306, sys_eventfd, 1)
+#define __NR_recvmmsg                           307
+__SYSCALL(307, sys_recvmmsg, 5)
 
-#define __NR_syscall_count                      307
+#define __NR_syscall_count                      308
 
 /*
  * sysxtensa syscall handler