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>

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 71bcc4b..1b59b1e 100644 (file)
--- 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;