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coredump: move mm->core_waiters into struct core_state

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Move mm->core_waiters into "struct core_state" allocated on stack.  This
shrinks mm_struct a little bit and allows further changes.

This patch mostly does s/core_waiters/core_state.  The only essential
change is that coredump_wait() must clear mm->core_state before return.

The coredump_wait()'s path is uglified and .text grows by 30 bytes, this
is fixed by the next patch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov
2008-07-25 01:47:41 -07:00
committed by Linus Torvalds
parent 32ecb1f26d
commit 999d9fc167
5 changed files with 19 additions and 18 deletions
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21
fs/exec.c
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@@ -722,12 +722,10 @@ static int exec_mmap(struct mm_struct *mm)
* Make sure that if there is a core dump in progress
* for the old mm, we get out and die instead of going
* through with the exec. We must hold mmap_sem around
* checking core_waiters and changing tsk->mm. The
* core-inducing thread will increment core_waiters for
* each thread whose ->mm == old_mm.
* checking core_state and changing tsk->mm.
*/
down_read(&old_mm->mmap_sem);
if (unlikely(old_mm->core_waiters)) {
if (unlikely(old_mm->core_state)) {
up_read(&old_mm->mmap_sem);
return -EINTR;
}
@@ -1514,7 +1512,7 @@ static void zap_process(struct task_struct *start)
t = start;
do {
if (t != current && t->mm) {
t->mm->core_waiters++;
t->mm->core_state->nr_threads++;
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
}
@@ -1538,11 +1536,11 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
if (err)
return err;
if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
if (atomic_read(&mm->mm_users) == mm->core_state->nr_threads + 1)
goto done;
/*
* We should find and kill all tasks which use this mm, and we should
* count them correctly into mm->core_waiters. We don't take tasklist
* count them correctly into ->nr_threads. We don't take tasklist
* lock, but this is safe wrt:
*
* fork:
@@ -1590,7 +1588,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
}
rcu_read_unlock();
done:
return mm->core_waiters;
return mm->core_state->nr_threads;
}
static int coredump_wait(int exit_code)
@@ -1603,9 +1601,12 @@ static int coredump_wait(int exit_code)
init_completion(&mm->core_done);
init_completion(&core_state.startup);
core_state.nr_threads = 0;
mm->core_state = &core_state;
core_waiters = zap_threads(tsk, mm, exit_code);
if (core_waiters < 0)
mm->core_state = NULL;
up_write(&mm->mmap_sem);
if (unlikely(core_waiters < 0))
@@ -1623,8 +1624,8 @@ static int coredump_wait(int exit_code)
if (core_waiters)
wait_for_completion(&core_state.startup);
mm->core_state = NULL;
fail:
BUG_ON(mm->core_waiters);
return core_waiters;
}
@@ -1702,7 +1703,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
/*
* If another thread got here first, or we are not dumpable, bail out.
*/
if (mm->core_waiters || !get_dumpable(mm)) {
if (mm->core_state || !get_dumpable(mm)) {
up_write(&mm->mmap_sem);
goto fail;
}