| Message ID | 20190624144151.22688-14-rpenyaev@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | epoll: support pollable epoll from userspace | expand |
On Mon, Jun 24, 2019 at 4:42 PM Roman Penyaev <rpenyaev@suse.de> wrote: > > epoll_create2() is needed to accept EPOLL_USERPOLL flags > and size, i.e. this patch wires up polling from userspace. Can you explain in the patch description more what it's needed for? The man page only states that "Since Linux 2.6.8, the size argument is ignored", so your description above does not explain why you need to add the size argument back. > diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl > index 1db9bbcfb84e..a1d7b695063d 100644 > --- a/arch/alpha/kernel/syscalls/syscall.tbl > +++ b/arch/alpha/kernel/syscalls/syscall.tbl > @@ -474,3 +474,5 @@ > 542 common fsmount sys_fsmount > 543 common fspick sys_fspick > 544 common pidfd_open sys_pidfd_open > +# 546 common clone3 sys_clone3 > +547 common epoll_create2 sys_epoll_create2 > diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl > index ff45d8807cb8..1497f3c87d54 100644 > --- a/arch/arm/tools/syscall.tbl > +++ b/arch/arm/tools/syscall.tbl > @@ -449,3 +449,4 @@ > 433 common fspick sys_fspick > 434 common pidfd_open sys_pidfd_open > 436 common clone3 sys_clone3 > +437 common epoll_create2 sys_epoll_create2 The table changes all look correct and complete, provided we don't get another patch picking the same number. Arnd
On 2019-06-24 18:14, Arnd Bergmann wrote: > On Mon, Jun 24, 2019 at 4:42 PM Roman Penyaev <rpenyaev@suse.de> wrote: >> >> epoll_create2() is needed to accept EPOLL_USERPOLL flags >> and size, i.e. this patch wires up polling from userspace. > > Can you explain in the patch description more what it's needed for? Sure. Will update on next iteration. > > The man page only states that "Since Linux 2.6.8, the size argument > is ignored", so your description above does not explain why you need > to add the size argument back. > >> diff --git a/arch/alpha/kernel/syscalls/syscall.tbl >> b/arch/alpha/kernel/syscalls/syscall.tbl >> index 1db9bbcfb84e..a1d7b695063d 100644 >> --- a/arch/alpha/kernel/syscalls/syscall.tbl >> +++ b/arch/alpha/kernel/syscalls/syscall.tbl >> @@ -474,3 +474,5 @@ >> 542 common fsmount sys_fsmount >> 543 common fspick sys_fspick >> 544 common pidfd_open sys_pidfd_open >> +# 546 common clone3 sys_clone3 >> +547 common epoll_create2 sys_epoll_create2 >> diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl >> index ff45d8807cb8..1497f3c87d54 100644 >> --- a/arch/arm/tools/syscall.tbl >> +++ b/arch/arm/tools/syscall.tbl >> @@ -449,3 +449,4 @@ >> 433 common fspick sys_fspick >> 434 common pidfd_open sys_pidfd_open >> 436 common clone3 sys_clone3 >> +437 common epoll_create2 sys_epoll_create2 > > The table changes all look correct and complete, provided we > don't get another patch picking the same number. Good. I had doubts, because on some archs there is a gap, (sys_clone3 was missing). So I left a placeholder, so can be uncommented when sys_clone3 is implemented. -- Roman
Roman Penyaev <rpenyaev@suse.de> wrote: > epoll_create2() is needed to accept EPOLL_USERPOLL flags > and size, i.e. this patch wires up polling from userspace. Instead of adding a new syscall, is setting size (and/or even the EPOLL_USEREPOLL flag) something that could be done via ioctl? There's no race like CLOEXEC to worry about and it's not going to be in a hot path where the extra syscall matters. glibc won't need to increase in .so size, either.
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl index 1db9bbcfb84e..a1d7b695063d 100644 --- a/arch/alpha/kernel/syscalls/syscall.tbl +++ b/arch/alpha/kernel/syscalls/syscall.tbl @@ -474,3 +474,5 @@ 542 common fsmount sys_fsmount 543 common fspick sys_fspick 544 common pidfd_open sys_pidfd_open +# 546 common clone3 sys_clone3 +547 common epoll_create2 sys_epoll_create2 diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index ff45d8807cb8..1497f3c87d54 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -449,3 +449,4 @@ 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h index e4e0523102e2..7fb8d77e2340 100644 --- a/arch/arm64/include/asm/unistd.h +++ b/arch/arm64/include/asm/unistd.h @@ -44,7 +44,7 @@ #define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5) #define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800) -#define __NR_compat_syscalls 437 +#define __NR_compat_syscalls 438 #endif #define __ARCH_WANT_SYS_CLONE diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index 10f16b0175ca..eb467e639352 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -890,6 +890,8 @@ __SYSCALL(__NR_fspick, sys_fspick) __SYSCALL(__NR_pidfd_open, sys_pidfd_open) #define __NR_clone3 436 __SYSCALL(__NR_clone3, sys_clone3) +#define __NR_epoll_create2 437 +__SYSCALL(__NR_epoll_create2, sys_epoll_create2) /* * Please add new compat syscalls above this comment and update diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl index ecc44926737b..5cecff901853 100644 --- a/arch/ia64/kernel/syscalls/syscall.tbl +++ b/arch/ia64/kernel/syscalls/syscall.tbl @@ -355,3 +355,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl index 9a3eb2558568..29d944e2e9d6 100644 --- a/arch/m68k/kernel/syscalls/syscall.tbl +++ b/arch/m68k/kernel/syscalls/syscall.tbl @@ -434,3 +434,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl index 9181f181f76d..fad83841b16b 100644 --- a/arch/microblaze/kernel/syscalls/syscall.tbl +++ b/arch/microblaze/kernel/syscalls/syscall.tbl @@ -441,3 +441,4 @@ 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index 97035e19ad03..661d63d7ea84 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -373,3 +373,5 @@ 432 n32 fsmount sys_fsmount 433 n32 fspick sys_fspick 434 n32 pidfd_open sys_pidfd_open +# 436 n32 clone3 sys_clone3 +437 n32 epoll_create2 sys_epoll_create2 diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index d7292722d3b0..4a7f270ef126 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -349,3 +349,5 @@ 432 n64 fsmount sys_fsmount 433 n64 fspick sys_fspick 434 n64 pidfd_open sys_pidfd_open +# 436 n64 clone3 sys_clone3 +437 n64 epoll_create2 sys_epoll_create2 diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index dba084c92f14..db87225a9dc5 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -422,3 +422,5 @@ 432 o32 fsmount sys_fsmount 433 o32 fspick sys_fspick 434 o32 pidfd_open sys_pidfd_open +# 436 o32 clone3 sys_clone3 +437 o32 epoll_create2 sys_epoll_create2 diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index 5022b9e179c2..25374a2c4e16 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -431,3 +431,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index f2c3bda2d39f..9f48d8a737ab 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -516,3 +516,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index 6ebacfeaf853..0cef54850a1c 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -437,3 +437,5 @@ 432 common fsmount sys_fsmount sys_fsmount 433 common fspick sys_fspick sys_fspick 434 common pidfd_open sys_pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 sys_epoll_create2 diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl index 834c9c7d79fa..42769d6ec8fe 100644 --- a/arch/sh/kernel/syscalls/syscall.tbl +++ b/arch/sh/kernel/syscalls/syscall.tbl @@ -437,3 +437,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl index c58e71f21129..bf86fa32913d 100644 --- a/arch/sparc/kernel/syscalls/syscall.tbl +++ b/arch/sparc/kernel/syscalls/syscall.tbl @@ -480,3 +480,5 @@ 432 common fsmount sys_fsmount 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open +# 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 6a99dbbf7e04..26d64f09b097 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -440,3 +440,4 @@ 433 i386 fspick sys_fspick __ia32_sys_fspick 434 i386 pidfd_open sys_pidfd_open __ia32_sys_pidfd_open 436 i386 clone3 sys_clone3 __ia32_sys_clone3 +437 i386 epoll_create2 sys_epoll_create2 __ia32_sys_epoll_create2 diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 68227c7f71e5..4b58d8694693 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -357,6 +357,7 @@ 433 common fspick __x64_sys_fspick 434 common pidfd_open __x64_sys_pidfd_open 436 common clone3 __x64_sys_clone3/ptregs +437 common epoll_create2 __x64_sys_epoll_create2 # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl index d5a1fd2c96c7..eef4367d433e 100644 --- a/arch/xtensa/kernel/syscalls/syscall.tbl +++ b/arch/xtensa/kernel/syscalls/syscall.tbl @@ -406,3 +406,4 @@ 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open 436 common clone3 sys_clone3 +437 common epoll_create2 sys_epoll_create2 diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 34239564bdfb..c3379bb4209b 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2825,6 +2825,11 @@ static int do_epoll_create(int flags, size_t size) return error; } +SYSCALL_DEFINE2(epoll_create2, int, flags, size_t, size) +{ + return do_epoll_create(flags, size); +} + SYSCALL_DEFINE1(epoll_create1, int, flags) { return do_epoll_create(flags, 0); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index b01d54a5732e..655ac0ebfdf9 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -357,6 +357,7 @@ asmlinkage long sys_eventfd2(unsigned int count, int flags); /* fs/eventpoll.c */ asmlinkage long sys_epoll_create1(int flags); +asmlinkage long sys_epoll_create2(int flags, size_t size); asmlinkage long sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event); asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 7c7c14a2e097..59c9dea64565 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -848,9 +848,11 @@ __SYSCALL(__NR_fspick, sys_fspick) __SYSCALL(__NR_pidfd_open, sys_pidfd_open) #define __NR_clone3 436 __SYSCALL(__NR_clone3, sys_clone3) +#define __NR_epoll_create2 437 +__SYSCALL(__NR_epoll_create2, sys_epoll_create2) #undef __NR_syscalls -#define __NR_syscalls 437 +#define __NR_syscalls 438 /* * 32 bit systems traditionally used different diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 34b76895b81e..090ff3aa7568 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -65,6 +65,7 @@ COND_SYSCALL(eventfd2); /* fs/eventfd.c */ COND_SYSCALL(epoll_create1); +COND_SYSCALL(epoll_create2); COND_SYSCALL(epoll_ctl); COND_SYSCALL(epoll_pwait); COND_SYSCALL_COMPAT(epoll_pwait);
epoll_create2() is needed to accept EPOLL_USERPOLL flags and size, i.e. this patch wires up polling from userspace. Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- arch/alpha/kernel/syscalls/syscall.tbl | 2 ++ arch/arm/tools/syscall.tbl | 1 + arch/arm64/include/asm/unistd.h | 2 +- arch/arm64/include/asm/unistd32.h | 2 ++ arch/ia64/kernel/syscalls/syscall.tbl | 2 ++ arch/m68k/kernel/syscalls/syscall.tbl | 2 ++ arch/microblaze/kernel/syscalls/syscall.tbl | 1 + arch/mips/kernel/syscalls/syscall_n32.tbl | 2 ++ arch/mips/kernel/syscalls/syscall_n64.tbl | 2 ++ arch/mips/kernel/syscalls/syscall_o32.tbl | 2 ++ arch/parisc/kernel/syscalls/syscall.tbl | 2 ++ arch/powerpc/kernel/syscalls/syscall.tbl | 2 ++ arch/s390/kernel/syscalls/syscall.tbl | 2 ++ arch/sh/kernel/syscalls/syscall.tbl | 2 ++ arch/sparc/kernel/syscalls/syscall.tbl | 2 ++ arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/xtensa/kernel/syscalls/syscall.tbl | 1 + fs/eventpoll.c | 5 +++++ include/linux/syscalls.h | 1 + include/uapi/asm-generic/unistd.h | 4 +++- kernel/sys_ni.c | 1 + 22 files changed, 40 insertions(+), 2 deletions(-)