task_struct cleanup: move binfmt field to mm_struct

Because the binfmt is not different between threads in the same process,
it can be moved from task_struct to mm_struct.  And binfmt moudle is
handled per mm_struct instead of task_struct.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 6dc92c3..d49be6b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1397,10 +1397,12 @@ out_ret:
 
 void set_binfmt(struct linux_binfmt *new)
 {
-	if (current->binfmt)
-		module_put(current->binfmt->module);
+	struct mm_struct *mm = current->mm;
+
+	if (mm->binfmt)
+		module_put(mm->binfmt->module);
 
-	current->binfmt = new;
+	mm->binfmt = new;
 	if (new)
 		__module_get(new->module);
 }
@@ -1770,7 +1772,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
 
 	audit_core_dumps(signr);
 
-	binfmt = current->binfmt;
+	binfmt = mm->binfmt;
 	if (!binfmt || !binfmt->core_dump)
 		goto fail;