mm: use mm->exe_file instead of first VM_EXECUTABLE vma->vm_file

Some security modules and oprofile still uses VM_EXECUTABLE for retrieving
a task's executable file.  After this patch they will use mm->exe_file
directly.  mm->exe_file is protected with mm->mmap_sem, so locking stays
the same.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>			[arch/tile]
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>	[tomoyo]
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/oprofile/cell/spu_task_sync.c

@@ -304,7 +304,7 @@ static inline unsigned long fast_get_dcookie(struct path *path)
 	return cookie;
 }
 
-/* Look up the dcookie for the task's first VM_EXECUTABLE mapping,
+/* Look up the dcookie for the task's mm->exe_file,
  * which corresponds loosely to "application name". Also, determine
  * the offset for the SPU ELF object.  If computed offset is
  * non-zero, it implies an embedded SPU object; otherwise, it's a
@@ -321,7 +321,6 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int *offsetp,
 {
 	unsigned long app_cookie = 0;
 	unsigned int my_offset = 0;
-	struct file *app = NULL;
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = spu->mm;
 
@@ -330,16 +329,10 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int *offsetp,
 
 	down_read(&mm->mmap_sem);
 
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (!vma->vm_file)
-			continue;
-		if (!(vma->vm_flags & VM_EXECUTABLE))
-			continue;
-		app_cookie = fast_get_dcookie(&vma->vm_file->f_path);
+	if (mm->exe_file) {
+		app_cookie = fast_get_dcookie(&mm->exe_file->f_path);
 		pr_debug("got dcookie for %s\n",
-			 vma->vm_file->f_dentry->d_name.name);
-		app = vma->vm_file;
-		break;
+			 mm->exe_file->f_dentry->d_name.name);
 	}
 
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {