From: Oleg Nesterov Date: Wed, 26 May 2010 21:43:04 +0000 (-0700) Subject: call_usermodehelper: simplify/fix UMH_NO_WAIT case X-Git-Tag: v2.6.35-rc1~177 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=d47419cd967a4f032a194148a7b08afad32faded;p=~emulex%2Finfiniband.git call_usermodehelper: simplify/fix UMH_NO_WAIT case __call_usermodehelper(UMH_NO_WAIT) has 2 problems: - if kernel_thread() fails, call_usermodehelper_freeinfo() is not called. - for unknown reason UMH_NO_WAIT has UMH_WAIT_PROC logic, we spawn yet another thread which waits until the user mode application exits. Change the UMH_NO_WAIT code to use ____call_usermodehelper() instead of wait_for_helper(), and do call_usermodehelper_freeinfo() unconditionally. We can rely on CLONE_VFORK, do_fork(CLONE_VFORK) until the child exits or execs. With or without this patch UMH_NO_WAIT does not report the error if kernel_thread() fails, this is correct since the caller doesn't wait for result. Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/kmod.c b/kernel/kmod.c index 48daed4c51b..ad9f2edebd6 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -205,10 +205,7 @@ static int wait_for_helper(void *data) sub_info->retval = ret; } - if (sub_info->wait == UMH_NO_WAIT) - call_usermodehelper_freeinfo(sub_info); - else - complete(sub_info->complete); + complete(sub_info->complete); return 0; } @@ -217,13 +214,13 @@ static void __call_usermodehelper(struct work_struct *work) { struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); - pid_t pid; enum umh_wait wait = sub_info->wait; + pid_t pid; /* CLONE_VFORK: wait until the usermode helper has execve'd * successfully We need the data structures to stay around * until that is done. */ - if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) + if (wait == UMH_WAIT_PROC) pid = kernel_thread(wait_for_helper, sub_info, CLONE_FS | CLONE_FILES | SIGCHLD); else @@ -232,6 +229,7 @@ static void __call_usermodehelper(struct work_struct *work) switch (wait) { case UMH_NO_WAIT: + call_usermodehelper_freeinfo(sub_info); break; case UMH_WAIT_PROC: