The patch titled
coredump: elf_core_dump: use core_state->dumper list
has been added to the -mm tree. Its filename is
coredump-elf_core_dump-use-core_state-dumper-list.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: coredump: elf_core_dump: use core_state->dumper list
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Kill the nasty rcu_read_lock() + do_each_thread() loop, use the list
encoded in mm->core_state instead, s/GFP_ATOMIC/GFP_KERNEL/.
This patch allows futher cleanups in binfmt_elf.c, in particular we can
kill the parallel info->threads list.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 77 +++++++++++++++++++---------------------------
1 file changed, 32 insertions(+), 45 deletions(-)
diff -puN fs/binfmt_elf.c~coredump-elf_core_dump-use-core_state-dumper-list fs/binfmt_elf.c
--- a/fs/binfmt_elf.c~coredump-elf_core_dump-use-core_state-dumper-list
+++ a/fs/binfmt_elf.c
@@ -1478,7 +1478,7 @@ static int fill_note_info(struct elfhdr
const struct user_regset_view *view = task_user_regset_view(dump_task);
struct elf_thread_core_info *t;
struct elf_prpsinfo *psinfo;
- struct task_struct *g, *p;
+ struct core_thread *ct;
unsigned int i;
info->size = 0;
@@ -1517,34 +1517,26 @@ static int fill_note_info(struct elfhdr
/*
* Allocate a structure for each thread.
*/
- rcu_read_lock();
- do_each_thread(g, p)
- if (p->mm == dump_task->mm) {
- if (p->flags & PF_KTHREAD)
- continue;
-
- t = kzalloc(offsetof(struct elf_thread_core_info,
- notes[info->thread_notes]),
- GFP_ATOMIC);
- if (unlikely(!t)) {
- rcu_read_unlock();
- return 0;
- }
- t->task = p;
- if (p == dump_task || !info->thread) {
- t->next = info->thread;
- info->thread = t;
- } else {
- /*
- * Make sure to keep the original task at
- * the head of the list.
- */
- t->next = info->thread->next;
- info->thread->next = t;
- }
+ for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
+ t = kzalloc(offsetof(struct elf_thread_core_info,
+ notes[info->thread_notes]),
+ GFP_KERNEL);
+ if (unlikely(!t))
+ return 0;
+
+ t->task = ct->task;
+ if (ct->task == dump_task || !info->thread) {
+ t->next = info->thread;
+ info->thread = t;
+ } else {
+ /*
+ * Make sure to keep the original task at
+ * the head of the list.
+ */
+ t->next = info->thread->next;
+ info->thread->next = t;
}
- while_each_thread(g, p);
- rcu_read_unlock();
+ }
/*
* Now fill in each thread's information.
@@ -1691,7 +1683,6 @@ static int fill_note_info(struct elfhdr
{
#define NUM_NOTES 6
struct list_head *t;
- struct task_struct *g, *p;
info->notes = NULL;
info->prstatus = NULL;
@@ -1723,23 +1714,19 @@ static int fill_note_info(struct elfhdr
info->thread_status_size = 0;
if (signr) {
+ struct core_thread *ct;
struct elf_thread_status *ets;
- rcu_read_lock();
- do_each_thread(g, p)
- if (current->mm == p->mm && current != p) {
- if (p->flags & PF_KTHREAD)
- continue;
-
- ets = kzalloc(sizeof(*ets), GFP_ATOMIC);
- if (!ets) {
- rcu_read_unlock();
- return 0;
- }
- ets->thread = p;
- list_add(&ets->list, &info->thread_list);
- }
- while_each_thread(g, p);
- rcu_read_unlock();
+
+ for (ct = current->mm->core_state->dumper.next;
+ ct; ct = ct->next) {
+ ets = kzalloc(sizeof(*ets), GFP_KERNEL);
+ if (!ets)
+ return 0;
+
+ ets->thread = ct->task;
+ list_add(&ets->list, &info->thread_list);
+ }
+
list_for_each(t, &info->thread_list) {
int sz;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
migrate_timers-add-comment-use-spinlock_irq.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup.patch
posix-timers-timer_delete-remove-the-bogus-it_process-=-null-check.patch
posix-timers-release_posix_timer-kill-the-bogus-put_task_struct-it_process.patch
signals-collect_signal-remove-the-unneeded-sigismember-check.patch
signals-collect_signal-simplify-the-still_pending-logic.patch
signals-change-collect_signal-to-return-void.patch
__exit_signal-dont-take-rcu-lock.patch
signals-dequeue_signal-dont-check-signal_group_exit-when-setting-signal_stop_dequeued.patch
signals-do_signal_stop-kill-the-signal_unkillable-check.patch
coredump-zap_threads-comments-use-while_each_thread.patch
signals-make-siginfo_t-si_utime-si_sstime-report-times-in-user_hz-not-hz.patch
kernel-signalc-change-vars-pid-and-tgid-types-to-pid_t.patch
include-asm-ptraceh-userspace-headers-cleanup.patch
ptrace-give-more-respect-to-sigkill.patch
ptrace-simplify-ptrace_stop-sigkill_pending-path.patch
introduce-pf_kthread-flag.patch
kill-pf_borrowed_mm-in-favour-of-pf_kthread.patch
coredump-zap_threads-must-skip-kernel-threads.patch
coredump-elf_core_dump-skip-kernel-threads.patch
coredump-turn-mm-core_startup_done-into-the-pointer-to-struct-core_state.patch
coredump-move-mm-core_waiters-into-struct-core_state.patch
coredump-simplify-core_state-nr_threads-calculation.patch
coredump-turn-core_state-nr_threads-into-atomic_t.patch
coredump-make-mm-core_state-visible-to-core_dump.patch
coredump-construct-the-list-of-coredumping-threads-at-startup-time.patch
coredump-elf_core_dump-use-core_state-dumper-list.patch
coredump-elf_fdpic_core_dump-use-core_state-dumper-list.patch
coredump-kill-mm-core_done.patch
workqueues-insert_work-use-list_head-instead-of-int-tail.patch
workqueues-implement-flush_work.patch
workqueues-schedule_on_each_cpu-use-flush_work.patch
workqueues-make-get_online_cpus-useable-for-work-func.patch
workqueues-make-get_online_cpus-useable-for-work-func-fix.patch
s390-topology-dont-use-kthread-for-arch_reinit_sched_domains.patch
workqueues-lockdep-annotations-for-flush_work.patch
workqueues-queue_work-can-use-queue_work_on.patch
workqueues-schedule_on_each_cpu-can-use-schedule_work_on.patch
pidns-remove-now-unused-kill_proc-function.patch
pidns-remove-now-unused-find_pid-function.patch
pidns-remove-find_task_by_pid-unused-for-a-long-time.patch
distinct-tgid-tid-i-o-statistics.patch
--
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