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>

6 files changed, 19 insertions, 57 deletions

diff --git a/arch/powerpc/oprofile/cell/spu_task_sync.c b/arch/powerpc/oprofile/cell/spu_task_sync.c
index 642fca137ccb..28f1af2db1f5 100644
--- a/arch/powerpc/oprofile/cell/spu_task_sync.c
+++ b/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) {
diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 758b6038c2b7..3cfa98bf9125 100644
--- a/arch/tile/mm/elf.c
+++ b/arch/tile/mm/elf.c
@@ -36,19 +36,14 @@ static void sim_notify_exec(const char *binary_name)
         } while (c);
 }
 
-static int notify_exec(void)
+static int notify_exec(struct mm_struct *mm)
 {
         int retval = 0;  /* failure */
-        struct vm_area_struct *vma = current->mm->mmap;
-        while (vma) {
-                if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
-                        break;
-                vma = vma->vm_next;
-        }
-        if (vma) {
+
+        if (mm->exe_file) {
                 char *buf = (char *) __get_free_page(GFP_KERNEL);
                 if (buf) {
-                        char *path = d_path(&vma->vm_file->f_path,
+                        char *path = d_path(&mm->exe_file->f_path,
                                             buf, PAGE_SIZE);
                         if (!IS_ERR(path)) {
                                 sim_notify_exec(path);
@@ -106,16 +101,16 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
         unsigned long vdso_base;
         int retval = 0;
 
+        down_write(&mm->mmap_sem);
+
         /*
          * Notify the simulator that an exec just occurred.
          * If we can't find the filename of the mapping, just use
          * whatever was passed as the linux_binprm filename.
          */
-        if (!notify_exec())
+        if (!notify_exec(mm))
                 sim_notify_exec(bprm->filename);
 
-        down_write(&mm->mmap_sem);
-
         /*
          * MAYWRITE to allow gdb to COW and set breakpoints
          */
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index f34b5b29fb95..d93b2b6b1f7a 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -216,7 +216,7 @@ static inline unsigned long fast_get_dcookie(struct path *path)
 }
 
 
-/* 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". This is
  * not strictly necessary but allows oprofile to associate
  * shared-library samples with particular applications
@@ -224,21 +224,10 @@ static inline unsigned long fast_get_dcookie(struct path *path)
 static unsigned long get_exec_dcookie(struct mm_struct *mm)
 {
         unsigned long cookie = NO_COOKIE;
-        struct vm_area_struct *vma;
-
-        if (!mm)
-                goto out;
 
-        for (vma = mm->mmap; vma; vma = vma->vm_next) {
-                if (!vma->vm_file)
-                        continue;
-                if (!(vma->vm_flags & VM_EXECUTABLE))
-                        continue;
-                cookie = fast_get_dcookie(&vma->vm_file->f_path);
-                break;
-        }
+        if (mm && mm->exe_file)
+                cookie = fast_get_dcookie(&mm->exe_file->f_path);
 
-out:
         return cookie;
 }
 
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 29e090cc0e46..f4a7756f999c 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1151,7 +1151,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
         const struct cred *cred;
         char name[sizeof(tsk->comm)];
         struct mm_struct *mm = tsk->mm;
-        struct vm_area_struct *vma;
         char *tty;
 
         if (!ab)
@@ -1191,16 +1190,8 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 
         if (mm) {
                 down_read(&mm->mmap_sem);
-                vma = mm->mmap;
-                while (vma) {
-                        if ((vma->vm_flags & VM_EXECUTABLE) &&
-                            vma->vm_file) {
-                                audit_log_d_path(ab, " exe=",
-                                                 &vma->vm_file->f_path);
-                                break;
-                        }
-                        vma = vma->vm_next;
-                }
+                if (mm->exe_file)
+                        audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
                 up_read(&mm->mmap_sem);
         }
         audit_log_task_context(ab);
diff --git a/kernel/fork.c b/kernel/fork.c
index a2b1efc20928..a57a993681ed 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -656,8 +656,7 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
 {
         struct file *exe_file;
 
-        /* We need mmap_sem to protect against races with removal of
-         * VM_EXECUTABLE vmas */
+        /* We need mmap_sem to protect against races with removal of exe_file */
         down_read(&mm->mmap_sem);
         exe_file = mm->exe_file;
         if (exe_file)
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index 867558c98334..2952ba576fb9 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -949,18 +949,13 @@ bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
 const char *tomoyo_get_exe(void)
 {
         struct mm_struct *mm = current->mm;
-        struct vm_area_struct *vma;
         const char *cp = NULL;
 
         if (!mm)
                 return NULL;
         down_read(&mm->mmap_sem);
-        for (vma = mm->mmap; vma; vma = vma->vm_next) {
-                if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
-                        cp = tomoyo_realpath_from_path(&vma->vm_file->f_path);
-                        break;
-                }
-        }
+        if (mm->exe_file)
+                cp = tomoyo_realpath_from_path(&mm->exe_file->f_path);
         up_read(&mm->mmap_sem);
         return cp;
 }