Commit 8cf8b553 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR 

do_poll() returns -EINTR if interrupted and after that all its callers
have to translate it into -ERESTARTNOHAND.  Change do_poll() to return
-ERESTARTNOHAND and update (simplify) the callers.

Note that this also unifies all users of restore_saved_sigmask_unless(),
see the next patch.

Linus:

: The *right* return value will actually be then chosen by
: poll_select_copy_remaining(), which will turn ERESTARTNOHAND to EINTR
: when it can't update the timeout.
:
: Except for the cases that use restart_block and do that instead and
: don't have the whole timeout restart issue as a result.

Link: http://lkml.kernel.org/r/20190606140852.GB13440@redhat.com


Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Laight <David.Laight@aculab.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Eric Wong <e@80x24.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b772434b

fs/select.c

+7 −23
Original line number Diff line number Diff line
@@ -925,7 +925,7 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait, 
		if (!count) {

			count = wait->error;

			if (signal_pending(current))

				count = -EINTR;

				count = -ERESTARTNOHAND;

		}

		if (count || timed_out)

			break;
@@ -1040,7 +1040,7 @@ static long do_restart_poll(struct restart_block *restart_block) 


	ret = do_sys_poll(ufds, nfds, to);



	if (ret == -EINTR) {

	if (ret == -ERESTARTNOHAND) {

		restart_block->fn = do_restart_poll;

		ret = -ERESTART_RESTARTBLOCK;

	}
@@ -1061,7 +1061,7 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, 


	ret = do_sys_poll(ufds, nfds, to);



	if (ret == -EINTR) {

	if (ret == -ERESTARTNOHAND) {

		struct restart_block *restart_block;



		restart_block = &current->restart_block;
@@ -1102,11 +1102,7 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, 
		return ret;



	ret = do_sys_poll(ufds, nfds, to);



	restore_saved_sigmask_unless(ret == -EINTR);

	/* We can restart this syscall, usually */

	if (ret == -EINTR)

		ret = -ERESTARTNOHAND;

	restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);

	ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);



	return ret;
@@ -1135,11 +1131,7 @@ SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds, 
		return ret;



	ret = do_sys_poll(ufds, nfds, to);



	restore_saved_sigmask_unless(ret == -EINTR);

	/* We can restart this syscall, usually */

	if (ret == -EINTR)

		ret = -ERESTARTNOHAND;

	restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);

	ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);



	return ret;
@@ -1413,11 +1405,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, 
		return ret;



	ret = do_sys_poll(ufds, nfds, to);



	restore_saved_sigmask_unless(ret == -EINTR);

	/* We can restart this syscall, usually */

	if (ret == -EINTR)

		ret = -ERESTARTNOHAND;

	restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);

	ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);



	return ret;
@@ -1446,11 +1434,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds, 
		return ret;



	ret = do_sys_poll(ufds, nfds, to);



	restore_saved_sigmask_unless(ret == -EINTR);

	/* We can restart this syscall, usually */

	if (ret == -EINTR)

		ret = -ERESTARTNOHAND;

	restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);

	ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);



	return ret;

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