linux-kernel - [PATCH] Add kerneldoc for flush_scheduled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.44L0.0908111659510.5845-100000@iolanthe.rowland.org>
Date:	Tue, 11 Aug 2009 17:06:17 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	James Bottomley <James.Bottomley@...senPartnership.com>,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: [PATCH] Add kerneldoc for flush_scheduled_work()

This patch (as1279) adds kerneldoc for flush_scheduled_work()
containing a stern warning that the function should be avoided.

Signed-off-by: Alan Stern <stern@...land.harvard.edu>

---

Index: usb-2.6/kernel/workqueue.c
===================================================================
--- usb-2.6.orig/kernel/workqueue.c
+++ usb-2.6/kernel/workqueue.c
@@ -739,6 +739,24 @@ int schedule_on_each_cpu(work_func_t fun
 	return 0;
 }
 
+/**
+ * flush_scheduled_work - ensure that all work scheduled on keventd_wq has run to completion.
+ *
+ * Blocks until all works on the keventd_wq global workqueue have completed.
+ * We sleep until all works present upon entry have been handled, but we
+ * are not livelocked by new incoming ones.
+ *
+ * Use of this function is discouraged, as it is highly prone to deadlock.
+ * It should never be called from within a work routine on the global
+ * queue, and it should never be called while holding a mutex required
+ * by one of the works on the global queue.  But the fact that keventd_wq
+ * _is_ global means that it can contain works requiring practically any
+ * mutex.  Hence this routine shouldn't be called while holding any mutex.
+ *
+ * Consider using cancel_work_sync() or cancel_delayed_work_sync() instead.
+ * They don't do the same thing (they cancel the work instead of waiting
+ * for it to complete), but in most cases they will suffice.
+ */
 void flush_scheduled_work(void)
 {
 	flush_workqueue(keventd_wq);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/