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authorOleg Nesterov <oleg@redhat.com>2012-03-23 15:02:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-23 16:58:41 -0700
commitd0bd587a80960d7ba7e0c8396e154028c9045c54 (patch)
tree3765f8eccdc5f982ba173a7a05d8981d573b9486 /include/linux/kmod.h
parentb3449922502f5a161ee2b5022a33aec8472fbf18 (diff)
usermodehelper: implement UMH_KILLABLE
Implement UMH_KILLABLE, should be used along with UMH_WAIT_EXEC/PROC. The caller must ensure that subprocess_info->path/etc can not go away until call_usermodehelper_freeinfo(). call_usermodehelper_exec(UMH_KILLABLE) does wait_for_completion_killable. If it fails, it uses xchg(&sub_info->complete, NULL) to serialize with umh_complete() which does the same xhcg() to access sub_info->complete. If call_usermodehelper_exec wins, it can safely return. umh_complete() should get NULL and call call_usermodehelper_freeinfo(). Otherwise we know that umh_complete() was already called, in this case call_usermodehelper_exec() falls back to wait_for_completion() which should succeed "very soon". Note: UMH_NO_WAIT == -1 but it obviously should not be used with UMH_KILLABLE. We delay the neccessary cleanup to simplify the back porting. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/kmod.h')
-rw-r--r--include/linux/kmod.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 722f477c4ef7..1b5985855ffc 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -54,6 +54,8 @@ enum umh_wait {
UMH_WAIT_PROC = 1, /* wait for the process to complete */
};
+#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */
+
struct subprocess_info {
struct work_struct work;
struct completion *complete;