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| author | Oleg Nesterov <oleg@redhat.com> | 2012-03-23 15:02:47 -0700 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2013-06-10 11:42:15 +0200 |
| commit | e2a28e9a9f98d9a73ea5ce58328595dcab64a1f6 (patch) | |
| tree | 44e7aedc9c6d471bcc368451842a86091c1773ec /include | |
| parent | 13db73535cc63e0034b901a287cf5bb20919825b (diff) | |
| download | lwn-e2a28e9a9f98d9a73ea5ce58328595dcab64a1f6.tar.gz lwn-e2a28e9a9f98d9a73ea5ce58328595dcab64a1f6.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>
[dannf: backported to Debian's 2.6.32]
Signed-off-by: Willy Tarreau <w@1wt.eu>
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 0546fe7ef1af..93e732e04ea7 100644 --- a/include/linux/kmod.h +++ b/include/linux/kmod.h @@ -64,6 +64,8 @@ enum umh_wait { UMH_WAIT_PROC = 1, /* wait for the process to complete */ }; +#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */ + /* Actually execute the sub-process */ int call_usermodehelper_exec(struct subprocess_info *info, enum umh_wait wait); |