Re: [PATCH 32/32] aio: implement io_pgetevents
From: Jeff Moyer <hidden>
Date: 2018-01-12 20:44:56
Also in:
linux-api, linux-fsdevel, lkml
Christoph Hellwig [off-list ref] writes:
This is the io_getevents equivalent of ppoll/pselect and allows to properly mix signals and aio completions (especially with IOCB_CMD_POLL) and atomically executes the following sequence: sigset_t origmask; pthread_sigmask(SIG_SETMASK, &sigmask, &origmask); ret = io_getevents(ctx, min_nr, nr, events, timeout); pthread_sigmask(SIG_SETMASK, &origmask, NULL); Note that unlike many other signal related calls we do not pass a sigmask size, as that would get us to 7 arguments, which aren't easily supported by the syscall infrastructure. It seems a lot less painful to just add a new syscall variant in the unlikely case we're going to increase the sigset size.
pselect, as an example, crams the sigmask and size together. Why not just do that? libaio can take care of setting that up. Cheers, Jeff
quoted hunk
Signed-off-by: Christoph Hellwig <redacted> --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/aio.c | 96 ++++++++++++++++++++++++++++++---- include/linux/compat.h | 6 +++ include/linux/syscalls.h | 6 +++ include/uapi/asm-generic/unistd.h | 4 +- kernel/sys_ni.c | 2 + 7 files changed, 105 insertions(+), 11 deletions(-)diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 448ac2161112..5997c3e9ac3e 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl@@ -391,3 +391,4 @@ 382 i386 pkey_free sys_pkey_free 383 i386 statx sys_statx 384 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl +385 i386 io_pgetevents sys_io_pgetevents compat_sys_io_pgeteventsdiff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 5aef183e2f85..e995cd2b4e65 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl@@ -339,6 +339,7 @@ 330 common pkey_alloc sys_pkey_alloc 331 common pkey_free sys_pkey_free 332 common statx sys_statx +333 common io_pgetevents sys_io_pgetevents # # x32-specific system call numbers start at 512 to avoid cache impactdiff --git a/fs/aio.c b/fs/aio.c index cae90ac6e4a3..57a4e8d89f78 100644 --- a/fs/aio.c +++ b/fs/aio.c@@ -1299,10 +1299,6 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr, wait_event_interruptible_hrtimeout(ctx->wait, aio_read_events(ctx, min_nr, nr, event, &ret), until); - - if (!ret && signal_pending(current)) - ret = -EINTR; - return ret; }@@ -1978,13 +1974,54 @@ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, struct timespec __user *, timeout) { struct timespec64 ts; + int ret; + + if (timeout && unlikely(get_timespec64(&ts, timeout))) + return -EFAULT; - if (timeout) { - if (unlikely(get_timespec64(&ts, timeout))) + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); + if (!ret && signal_pending(current)) + ret = -EINTR; + return ret; +} + +SYSCALL_DEFINE6(io_pgetevents, + aio_context_t, ctx_id, + long, min_nr, + long, nr, + struct io_event __user *, events, + struct timespec __user *, timeout, + const sigset_t __user *, sigmask) +{ + sigset_t ksigmask, sigsaved; + struct timespec64 ts; + int ret; + + if (timeout && unlikely(get_timespec64(&ts, timeout))) + return -EFAULT; + + if (sigmask) { + if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) return -EFAULT; + sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); + sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); } - return do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); + if (signal_pending(current)) { + if (sigmask) { + current->saved_sigmask = sigsaved; + set_restore_sigmask(); + } + + if (!ret) + ret = -ERESTARTNOHAND; + } else { + if (sigmask) + sigprocmask(SIG_SETMASK, &sigsaved, NULL); + } + + return ret; } #ifdef CONFIG_COMPAT@@ -1995,13 +2032,52 @@ COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, struct compat_timespec __user *, timeout) { struct timespec64 t; + int ret; + + if (timeout && compat_get_timespec64(&t, timeout)) + return -EFAULT; + + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); + if (!ret && signal_pending(current)) + ret = -EINTR; + return ret; +} + +COMPAT_SYSCALL_DEFINE6(io_pgetevents, + compat_aio_context_t, ctx_id, + compat_long_t, min_nr, + compat_long_t, nr, + struct io_event __user *, events, + struct compat_timespec __user *, timeout, + const compat_sigset_t __user *, sigmask) +{ + sigset_t ksigmask, sigsaved; + struct timespec64 t; + int ret; - if (timeout) { - if (compat_get_timespec64(&t, timeout)) + if (timeout && compat_get_timespec64(&t, timeout)) + return -EFAULT; + + if (sigmask) { + if (get_compat_sigset(&ksigmask, sigmask)) return -EFAULT; + sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); + sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); + } + ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); + if (signal_pending(current)) { + if (sigmask) { + current->saved_sigmask = sigsaved; + set_restore_sigmask(); + } + if (!ret) + ret = -ERESTARTNOHAND; + } else { + if (sigmask) + sigprocmask(SIG_SETMASK, &sigsaved, NULL); } - return do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); + return ret; } #endifdiff --git a/include/linux/compat.h b/include/linux/compat.h index 0fc36406f32c..a4cda98073f1 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h@@ -536,6 +536,12 @@ asmlinkage long compat_sys_io_getevents(compat_aio_context_t ctx_id, compat_long_t nr, struct io_event __user *events, struct compat_timespec __user *timeout); +asmlinkage long compat_sys_io_pgetevents(compat_aio_context_t ctx_id, + compat_long_t min_nr, + compat_long_t nr, + struct io_event __user *events, + struct compat_timespec __user *timeout, + const compat_sigset_t __user *sigmask); asmlinkage long compat_sys_io_submit(compat_aio_context_t ctx_id, int nr, u32 __user *iocb); asmlinkage long compat_sys_mount(const char __user *dev_name,diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index a78186d826d7..3bc9a130f4a9 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h@@ -539,6 +539,12 @@ asmlinkage long sys_io_getevents(aio_context_t ctx_id, long nr, struct io_event __user *events, struct timespec __user *timeout); +asmlinkage long sys_io_pgetevents(aio_context_t ctx_id, + long min_nr, + long nr, + struct io_event __user *events, + struct timespec __user *timeout, + const sigset_t __user *sigmask); asmlinkage long sys_io_submit(aio_context_t, long, struct iocb __user * __user *); asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 8b87de067bc7..ce2ebbeece10 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h@@ -732,9 +732,11 @@ __SYSCALL(__NR_pkey_alloc, sys_pkey_alloc) __SYSCALL(__NR_pkey_free, sys_pkey_free) #define __NR_statx 291 __SYSCALL(__NR_statx, sys_statx) +#define __NR_io_pgetevents 292 +__SC_COMP(__NR_io_pgetevents, sys_io_pgetevents, compat_sys_io_pgetevents) #undef __NR_syscalls -#define __NR_syscalls 292 +#define __NR_syscalls 293 /* * All syscalls below here should go away really,diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index b5189762d275..8f7705559b38 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c@@ -151,9 +151,11 @@ cond_syscall(sys_io_destroy); cond_syscall(sys_io_submit); cond_syscall(sys_io_cancel); cond_syscall(sys_io_getevents); +cond_syscall(sys_io_pgetevents); cond_syscall(compat_sys_io_setup); cond_syscall(compat_sys_io_submit); cond_syscall(compat_sys_io_getevents); +cond_syscall(compat_sys_io_pgetevents); cond_syscall(sys_sysfs); cond_syscall(sys_syslog); cond_syscall(sys_process_vm_readv);