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| author | Mateusz Guzik <mguzik@redhat.com> | 2016-08-23 16:20:38 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-24 10:09:28 +0200 |
| commit | 2daa86f541b8fa873c56b3cc2c8dc32e03b864fc (patch) | |
| tree | 0d8f06c8344be97174422fd6478bd22b84aa4b07 /kernel | |
| parent | 78494c6237c82f0b45fab75c3b2988d00505992c (diff) | |
| download | lwn-2daa86f541b8fa873c56b3cc2c8dc32e03b864fc.tar.gz lwn-2daa86f541b8fa873c56b3cc2c8dc32e03b864fc.zip | |
mm: introduce get_task_exe_file
commit cd81a9170e69e018bbaba547c1fd85a585f5697a upstream.
For more convenient access if one has a pointer to the task.
As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.
Use the helper in proc_exe_link.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index aea4f4da3836..74fd39079031 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -801,6 +801,29 @@ struct file *get_mm_exe_file(struct mm_struct *mm) EXPORT_SYMBOL(get_mm_exe_file); /** + * get_task_exe_file - acquire a reference to the task's executable file + * + * Returns %NULL if task's mm (if any) has no associated executable file or + * this is a kernel thread with borrowed mm (see the comment above get_task_mm). + * User must release file via fput(). + */ +struct file *get_task_exe_file(struct task_struct *task) +{ + struct file *exe_file = NULL; + struct mm_struct *mm; + + task_lock(task); + mm = task->mm; + if (mm) { + if (!(task->flags & PF_KTHREAD)) + exe_file = get_mm_exe_file(mm); + } + task_unlock(task); + return exe_file; +} +EXPORT_SYMBOL(get_task_exe_file); + +/** * get_task_mm - acquire a reference to the task's mm * * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |