diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kmod.c | 44 |
1 files changed, 20 insertions, 24 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c index d38b2da..da98d05 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -265,15 +265,9 @@ out: do_exit(0); } -/* - * Handles UMH_WAIT_PROC. Our parent (unbound workqueue) might not be able to - * run enough instances to handle usermodehelper completions without blocking - * some other pending requests. That's why we use a kernel thread dedicated for - * that purpose. - */ -static int call_usermodehelper_exec_sync(void *data) +/* Handles UMH_WAIT_PROC. */ +static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) { - struct subprocess_info *sub_info = data; pid_t pid; /* If SIGCLD is ignored sys_wait4 won't populate the status. */ @@ -287,9 +281,9 @@ static int call_usermodehelper_exec_sync(void *data) * Normally it is bogus to call wait4() from in-kernel because * wait4() wants to write the exit code to a userspace address. * But call_usermodehelper_exec_sync() always runs as kernel - * thread and put_user() to a kernel address works OK for kernel - * threads, due to their having an mm_segment_t which spans the - * entire address space. + * thread (workqueue) and put_user() to a kernel address works + * OK for kernel threads, due to their having an mm_segment_t + * which spans the entire address space. * * Thus the __user pointer cast is valid here. */ @@ -304,19 +298,21 @@ static int call_usermodehelper_exec_sync(void *data) sub_info->retval = ret; } + /* Restore default kernel sig handler */ + kernel_sigaction(SIGCHLD, SIG_IGN); + umh_complete(sub_info); - do_exit(0); } /* - * This function doesn't strictly needs to be called asynchronously. But we - * need to create the usermodehelper kernel threads from a task that is affine + * We need to create the usermodehelper kernel thread from a task that is affine * to an optimized set of CPUs (or nohz housekeeping ones) such that they * inherit a widest affinity irrespective of call_usermodehelper() callers with * possibly reduced affinity (eg: per-cpu workqueues). We don't want * usermodehelper targets to contend a busy CPU. * - * Unbound workqueues provide such wide affinity. + * Unbound workqueues provide such wide affinity and allow to block on + * UMH_WAIT_PROC requests without blocking pending request (up to some limit). * * Besides, workqueues provide the privilege level that caller might not have * to perform the usermodehelper request. @@ -326,18 +322,18 @@ static void call_usermodehelper_exec_work(struct work_struct *work) { struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); - pid_t pid; - if (sub_info->wait & UMH_WAIT_PROC) - pid = kernel_thread(call_usermodehelper_exec_sync, sub_info, - CLONE_FS | CLONE_FILES | SIGCHLD); - else + if (sub_info->wait & UMH_WAIT_PROC) { + call_usermodehelper_exec_sync(sub_info); + } else { + pid_t pid; + pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); - - if (pid < 0) { - sub_info->retval = pid; - umh_complete(sub_info); + if (pid < 0) { + sub_info->retval = pid; + umh_complete(sub_info); + } } } |
