In the future mm->exe_file will be done without mmap_sem
serialization, thus isolate and reorganize the related
code to make the transition easier. Good users will, make
use of the more standard get_mm_exe_file(), requiring only
holding the mmap_sem to read the value, and relying on reference
counting to make sure that the exe file won't dissappear
underneath us while getting the dcookie.

Cc: Arnd Bergmann <a...@arndb.de>
Cc: Robert Richter <r...@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: cbe-oss-...@lists.ozlabs.org
Cc: oprofile-l...@lists.sourceforge.net
Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
---

Completely untested.

 arch/powerpc/oprofile/cell/spu_task_sync.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/oprofile/cell/spu_task_sync.c 
b/arch/powerpc/oprofile/cell/spu_task_sync.c
index 1c27831..ed7b097 100644
--- a/arch/powerpc/oprofile/cell/spu_task_sync.c
+++ b/arch/powerpc/oprofile/cell/spu_task_sync.c
@@ -22,6 +22,7 @@
 #include <linux/kref.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/file.h>
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/numa.h>
@@ -322,18 +323,20 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int 
*offsetp,
        unsigned long app_cookie = 0;
        unsigned int my_offset = 0;
        struct vm_area_struct *vma;
+       struct file *exe_file;
        struct mm_struct *mm = spu->mm;
 
        if (!mm)
                goto out;
 
-       down_read(&mm->mmap_sem);
-
-       if (mm->exe_file) {
-               app_cookie = fast_get_dcookie(&mm->exe_file->f_path);
-               pr_debug("got dcookie for %pD\n", mm->exe_file);
+       exe_file = get_mm_exe_file(mm);
+       if (exe_file) {
+               app_cookie = fast_get_dcookie(&exe_file->f_path);
+               pr_debug("got dcookie for %pD\n", exe_file);
+               fput(exe_file);
        }
 
+       down_read(&mm->mmap_sem);
        for (vma = mm->mmap; vma; vma = vma->vm_next) {
                if (vma->vm_start > spu_ref || vma->vm_end <= spu_ref)
                        continue;
-- 
2.1.4

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