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Commit fd89a65f authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

powerpc/oprofile: reduce mmap_sem hold for exe_file 



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.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robert Richter <rric@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11163348

arch/powerpc/oprofile/cell/spu_task_sync.c

+8 −5
Original line number Diff line number Diff line
@@ -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;