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| author | Oleg Nesterov <oleg@redhat.com> | 2012-03-23 15:02:47 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-06 03:24:27 +0000 |
| commit | ed549cef5a192eae889b36117beae72d4d68de79 (patch) | |
| tree | ef16edfa4d345b129443750e288be45ed101b384 /include | |
| parent | 3ba91066fd4f9b4340ae88ce5cb18cd4b58d9184 (diff) | |
| download | lwn-ed549cef5a192eae889b36117beae72d4d68de79.tar.gz lwn-ed549cef5a192eae889b36117beae72d4d68de79.zip | |
usermodehelper: implement UMH_KILLABLE
commit d0bd587a80960d7ba7e0c8396e154028c9045c54 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kmod.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/kmod.h b/include/linux/kmod.h index b16f65390734..f8d4b2719450 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; |