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Commit 7a074e96 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

aio: implement io_pgetevents 



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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent a3c0d439

arch/x86/entry/syscalls/syscall_32.tbl

+1 −0
Original line number Diff line number Diff line
@@ -396,3 +396,4 @@ 
382	i386	pkey_free		sys_pkey_free			__ia32_sys_pkey_free

383	i386	statx			sys_statx			__ia32_sys_statx

384	i386	arch_prctl		sys_arch_prctl			__ia32_compat_sys_arch_prctl

385	i386	io_pgetevents		sys_io_pgetevents		__ia32_compat_sys_io_pgetevents

arch/x86/entry/syscalls/syscall_64.tbl

+1 −0
Original line number Diff line number Diff line
@@ -341,6 +341,7 @@ 
330	common	pkey_alloc		__x64_sys_pkey_alloc

331	common	pkey_free		__x64_sys_pkey_free

332	common	statx			__x64_sys_statx

333	common	io_pgetevents		__x64_sys_io_pgetevents



#

# x32-specific system call numbers start at 512 to avoid cache impact

fs/aio.c

+104 −10
Original line number Diff line number Diff line
@@ -1303,10 +1303,6 @@ 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;

}
@@ -1921,13 +1917,60 @@ 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;



	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 struct __aio_sigset __user *, usig)

{

	struct __aio_sigset	ksig = { NULL, };

	sigset_t		ksigmask, sigsaved;

	struct timespec64	ts;

	int ret;



	if (timeout) {

		if (unlikely(get_timespec64(&ts, timeout)))

	if (timeout && unlikely(get_timespec64(&ts, timeout)))

		return -EFAULT;



	if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))

		return -EFAULT;



	if (ksig.sigmask) {

		if (ksig.sigsetsize != sizeof(sigset_t))

			return -EINVAL;

		if (copy_from_user(&ksigmask, ksig.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 (ksig.sigmask) {

			current->saved_sigmask = sigsaved;

			set_restore_sigmask();

		}



		if (!ret)

			ret = -ERESTARTNOHAND;

	} else {

		if (ksig.sigmask)

			sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	}



	return ret;

}



#ifdef CONFIG_COMPAT
@@ -1938,13 +1981,64 @@ COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, 
		       struct compat_timespec __user *, timeout)

{

	struct timespec64 t;

	int ret;



	if (timeout) {

		if (compat_get_timespec64(&t, timeout))

	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;

}



	return do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);



struct __compat_aio_sigset {

	compat_sigset_t __user	*sigmask;

	compat_size_t		sigsetsize;

};



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 struct __compat_aio_sigset __user *, usig)

{

	struct __compat_aio_sigset ksig = { NULL, };

	sigset_t ksigmask, sigsaved;

	struct timespec64 t;

	int ret;



	if (timeout && compat_get_timespec64(&t, timeout))

		return -EFAULT;



	if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))

		return -EFAULT;



	if (ksig.sigmask) {

		if (ksig.sigsetsize != sizeof(compat_sigset_t))

			return -EINVAL;

		if (get_compat_sigset(&ksigmask, ksig.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 (ksig.sigmask) {

			current->saved_sigmask = sigsaved;

			set_restore_sigmask();

		}

		if (!ret)

			ret = -ERESTARTNOHAND;

	} else {

		if (ksig.sigmask)

			sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	}



	return ret;

}

#endif

include/linux/compat.h

+7 −0
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ extern int put_compat_rusage(const struct rusage *, 
			     struct compat_rusage __user *);



struct compat_siginfo;

struct __compat_aio_sigset;



struct compat_dirent {

	u32		d_ino;
@@ -553,6 +554,12 @@ 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 struct __compat_aio_sigset __user *usig);



/* fs/cookies.c */

asmlinkage long compat_sys_lookup_dcookie(u32, u32, char __user *, compat_size_t);

include/linux/syscalls.h

+6 −0
Original line number Diff line number Diff line
@@ -290,6 +290,12 @@ 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 struct __aio_sigset *sig);



/* fs/xattr.c */

asmlinkage long sys_setxattr(const char __user *path, const char __user *name,