LU-8304 libcfs: convert debug_ctlwq to a completion.

[fs/lustre-release.git] / libcfs / libcfs / debug.c

diff --git a/libcfs/libcfs/debug.c b/libcfs/libcfs/debug.c
index 2b30ab0..f48d9e5 100644 (file)
--- a/libcfs/libcfs/debug.c
+++ b/libcfs/libcfs/debug.c
@@ -249,7 +249,7 @@ MODULE_PARM_DESC(libcfs_panic_on_lbug, "Lustre kernel panic on LBUG");
 atomic_t libcfs_kmemory = ATOMIC_INIT(0);
 EXPORT_SYMBOL(libcfs_kmemory);
 
-static wait_queue_head_t debug_ctlwq;
+static DECLARE_COMPLETION(debug_complete);
 
 char libcfs_debug_file_path_arr[PATH_MAX] = LIBCFS_DEBUG_FILE_PATH_DEFAULT;
 EXPORT_SYMBOL(libcfs_debug_file_path_arr);
@@ -386,8 +386,7 @@ void libcfs_debug_dumplog_internal(void *arg)
                snprintf(debug_file_name, sizeof(debug_file_name) - 1,
                         "%s.%lld.%ld", libcfs_debug_file_path_arr,
                         (s64)current_time, (uintptr_t)arg);
-               printk(KERN_ALERT "LustreError: dumping log to %s\n",
-                      debug_file_name);
+               pr_alert("LustreError: dumping log to %s\n", debug_file_name);
                cfs_tracefile_dump_all_pages(debug_file_name);
                libcfs_run_debug_log_upcall(debug_file_name);
        }
@@ -397,38 +396,30 @@ void libcfs_debug_dumplog_internal(void *arg)
 static int libcfs_debug_dumplog_thread(void *arg)
 {
        libcfs_debug_dumplog_internal(arg);
-       wake_up(&debug_ctlwq);
+       complete(&debug_complete);
        return 0;
 }
 
 void libcfs_debug_dumplog(void)
 {
-       wait_queue_entry_t wait;
        struct task_struct *dumper;
 
        ENTRY;
-
-       /*
-        * we're being careful to ensure that the kernel thread is
-        * able to set our state to running as it exits before we
-        * get to schedule()
+       /* If a previous call was interrupted, debug_complete->done
+        * might be elevated, and so we won't actually wait here.
+        * So we reinit the completion to ensure we wait for
+        * one thread to complete, though it might not be the one
+        * we start if there are overlaping thread.
         */
-       init_waitqueue_entry(&wait, current);
-       set_current_state(TASK_INTERRUPTIBLE);
-       add_wait_queue(&debug_ctlwq, &wait);
-
+       reinit_completion(&debug_complete);
        dumper = kthread_run(libcfs_debug_dumplog_thread,
                             (void *)(long)current_pid(),
                             "libcfs_debug_dumper");
        if (IS_ERR(dumper))
-               printk(KERN_ERR "LustreError: cannot start log dump thread:"
-                      " %ld\n", PTR_ERR(dumper));
+               pr_err("LustreError: cannot start log dump thread: rc = %ld\n",
+                      PTR_ERR(dumper));
        else
-               schedule();
-
-       /* be sure to teardown if cfs_create_thread() failed */
-       remove_wait_queue(&debug_ctlwq, &wait);
-       set_current_state(TASK_RUNNING);
+               wait_for_completion_interruptible(&debug_complete);
 }
 EXPORT_SYMBOL(libcfs_debug_dumplog);
 
@@ -437,8 +428,6 @@ int libcfs_debug_init(unsigned long bufsize)
        int rc = 0;
        unsigned int max = libcfs_debug_mb;
 
-       init_waitqueue_head(&debug_ctlwq);
-
        if (libcfs_console_max_delay <= 0 || /* not set by user or */
            libcfs_console_min_delay <= 0 || /* set to invalid values */
            libcfs_console_min_delay >= libcfs_console_max_delay) {