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Commit a94e2d40 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

coredump: kill mm->core_done 



Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.

This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion).  Also, with this change we can
decouple exit_mm() from the coredumping code.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 182c515f

fs/exec.c

+22 −3
Original line number Diff line number Diff line
@@ -1602,7 +1602,6 @@ static int coredump_wait(int exit_code, struct core_state *core_state) 
	struct completion *vfork_done;

	int core_waiters;



	init_completion(&mm->core_done);

	init_completion(&core_state->startup);

	core_state->dumper.task = tsk;

	core_state->dumper.next = NULL;
@@ -1628,6 +1627,27 @@ static int coredump_wait(int exit_code, struct core_state *core_state) 
	return core_waiters;

}



static void coredump_finish(struct mm_struct *mm)

{

	struct core_thread *curr, *next;

	struct task_struct *task;



	next = mm->core_state->dumper.next;

	while ((curr = next) != NULL) {

		next = curr->next;

		task = curr->task;

		/*

		 * see exit_mm(), curr->task must not see

		 * ->task == NULL before we read ->next.

		 */

		smp_mb();

		curr->task = NULL;

		wake_up_process(task);

	}



	mm->core_state = NULL;

}



/*

 * set_dumpable converts traditional three-value dumpable to two flags and

 * stores them into mm->flags.  It modifies lower two bits of mm->flags, but
@@ -1812,8 +1832,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) 
		argv_free(helper_argv);



	current->fsuid = fsuid;

	complete_all(&mm->core_done);

	mm->core_state = NULL;

	coredump_finish(mm);

fail:

	return retval;

}

include/linux/mm_types.h

+1 −3
Original line number Diff line number Diff line
@@ -229,9 +229,7 @@ struct mm_struct { 


	unsigned long flags; /* Must use atomic bitops to access the bits */



	/* coredumping support */

	struct core_state *core_state;

	struct completion core_done;

	struct core_state *core_state; /* coredumping support */



	/* aio bits */

	rwlock_t		ioctx_list_lock;	/* aio lock */

kernel/exit.c

+7 −1
Original line number Diff line number Diff line
@@ -691,7 +691,13 @@ static void exit_mm(struct task_struct * tsk) 
		if (atomic_dec_and_test(&core_state->nr_threads))

			complete(&core_state->startup);



		wait_for_completion(&mm->core_done);

		for (;;) {

			set_task_state(tsk, TASK_UNINTERRUPTIBLE);

			if (!self.task) /* see coredump_finish() */

				break;

			schedule();

		}

		__set_task_state(tsk, TASK_RUNNING);

		down_read(&mm->mmap_sem);

	}

	atomic_inc(&mm->mm_count);