[PATCH 32/32] aio: implement io_pgetevents
From: Christoph Hellwig
Date: Wed Jan 10 2018 - 11:00:42 EST
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.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
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_pgetevents
diff --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 impact
diff --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;
}
#endif
diff --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);
--
2.14.2