coredump: elf_fdpic_core_dump: use core_state->dumper list

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_fdpic.c.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 17 deletions

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 71bcc4b4d088..1b59b1edf26d 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1573,7 +1573,6 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
         struct memelfnote *notes = NULL;
         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
-        struct task_struct *g, *p;
         LIST_HEAD(thread_list);
         struct list_head *t;
         elf_fpregset_t *fpu = NULL;
@@ -1622,23 +1621,19 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
 #endif
 
         if (signr) {
+                struct core_thread *ct;
                 struct elf_thread_status *tmp;
-                rcu_read_lock();
-                do_each_thread(g,p)
-                        if (current->mm == p->mm && current != p) {
-                                if (p->flags & PF_KTHREAD)
-                                        continue;
-
-                                tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
-                                if (!tmp) {
-                                        rcu_read_unlock();
-                                        goto cleanup;
-                                }
-                                tmp->thread = p;
-                                list_add(&tmp->list, &thread_list);
-                        }
-                while_each_thread(g,p);
-                rcu_read_unlock();
+
+                for (ct = current->mm->core_state->dumper.next;
+                                                ct; ct = ct->next) {
+                        tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
+                        if (!tmp)
+                                goto cleanup;
+
+                        tmp->thread = ct->task;
+                        list_add(&tmp->list, &thread_list);
+                }
+
                 list_for_each(t, &thread_list) {
                         struct elf_thread_status *tmp;
                         int sz;