Commit 5abbe51a authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Thomas Gleixner
Browse files

kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data() 



Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT.

Add a new helper which sets restart_block->fn and calls a dummy
arch_set_restart_data() helper.

Fixes: 609c19a3 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174641.GA17871@redhat.com
parent 1e28eed1

fs/select.c

+4 −6
Original line number Diff line number Diff line
@@ -1055,10 +1055,9 @@ static long do_restart_poll(struct restart_block *restart_block) 


	ret = do_sys_poll(ufds, nfds, to);



	if (ret == -ERESTARTNOHAND) {

		restart_block->fn = do_restart_poll;

		ret = -ERESTART_RESTARTBLOCK;

	}

	if (ret == -ERESTARTNOHAND)

		ret = set_restart_fn(restart_block, do_restart_poll);



	return ret;

}
@@ -1080,7 +1079,6 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, 
		struct restart_block *restart_block;



		restart_block = &current->restart_block;

		restart_block->fn = do_restart_poll;

		restart_block->poll.ufds = ufds;

		restart_block->poll.nfds = nfds;
@@ -1091,7 +1089,7 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, 
		} else

			restart_block->poll.has_timeout = 0;



		ret = -ERESTART_RESTARTBLOCK;

		ret = set_restart_fn(restart_block, do_restart_poll);

	}

	return ret;

}

include/linux/thread_info.h

+13 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/types.h>

#include <linux/bug.h>

#include <linux/restart_block.h>

#include <linux/errno.h>



#ifdef CONFIG_THREAD_INFO_IN_TASK

/*
@@ -59,6 +60,18 @@ enum syscall_work_bit { 


#ifdef __KERNEL__



#ifndef arch_set_restart_data

#define arch_set_restart_data(restart) do { } while (0)

#endif



static inline long set_restart_fn(struct restart_block *restart,

					long (*fn)(struct restart_block *))

{

	restart->fn = fn;

	arch_set_restart_data(restart);

	return -ERESTART_RESTARTBLOCK;

}



#ifndef THREAD_ALIGN

#define THREAD_ALIGN	THREAD_SIZE

#endif

kernel/futex.c

+1 −2
Original line number Diff line number Diff line
@@ -2728,14 +2728,13 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, 
		goto out;



	restart = &current->restart_block;

	restart->fn = futex_wait_restart;

	restart->futex.uaddr = uaddr;

	restart->futex.val = val;

	restart->futex.time = *abs_time;

	restart->futex.bitset = bitset;

	restart->futex.flags = flags | FLAGS_HAS_TIMEOUT;



	ret = -ERESTART_RESTARTBLOCK;

	ret = set_restart_fn(restart, futex_wait_restart);



out:

	if (to) {

kernel/time/alarmtimer.c

+1 −1
Original line number Diff line number Diff line
@@ -854,9 +854,9 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags, 
	if (flags == TIMER_ABSTIME)

		return -ERESTARTNOHAND;



	restart->fn = alarm_timer_nsleep_restart;

	restart->nanosleep.clockid = type;

	restart->nanosleep.expires = exp;

	set_restart_fn(restart, alarm_timer_nsleep_restart);

	return ret;

}

kernel/time/hrtimer.c

+1 −1
Original line number Diff line number Diff line
@@ -1957,9 +1957,9 @@ long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode, 
	}



	restart = &current->restart_block;

	restart->fn = hrtimer_nanosleep_restart;

	restart->nanosleep.clockid = t.timer.base->clockid;

	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);

	set_restart_fn(restart, hrtimer_nanosleep_restart);

out:

	destroy_hrtimer_on_stack(&t.timer);

	return ret;