From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 11 Dec 2002 23:52:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 11 Dec 2002 23:52:43 -0500 Received: from mta6.snfc21.pbi.net ([206.13.28.240]:45279 "EHLO mta6.snfc21.pbi.net") by vger.kernel.org with ESMTP id ; Wed, 11 Dec 2002 23:52:41 -0500 Date: Wed, 11 Dec 2002 21:04:51 -0800 From: David Brownell Subject: [patch 2.5.51] add wait_event() to To: linux-kernel@vger.kernel.org Message-id: <3DF818F3.6050308@pacbell.net> MIME-version: 1.0 Content-type: multipart/mixed; boundary="Boundary_(ID_YeqJ5GjQU34PMJZ5Hxdh2w)" X-Accept-Language: en-us, en, fr User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020513 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --Boundary_(ID_YeqJ5GjQU34PMJZ5Hxdh2w) Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7BIT Folk periodically talk about evolving the "struct completion" support ... here's one: int wait_event (struct completion *x, signed long timeout_jiffies); Returns zero if the event happened, nonzero if it timed out. An example timeout action might be to cancel a request then use wait_for_completion(x) to synchronize with that. It's been behaving for me so far. Questions from me: - Is this appropriate to merge as-is? The tradeoff I'm thinking of is code duplication; this patch avoids it ("smaller==better" rule-of-thumb) but maybe someone has real tuning knowledge, or a "standard" lk policy applies. Or there might be bugs or api transgressions. - One routine was unavailable to modules; now exported. That seemed to just be an oversight. This doesn't add an "interruptible wait" api mode, which I'd expect some others might find a use for. This patch will let us clean up some dubious code in usbcore which is more or less trying to do a wait_event(). Thanks in advance for any comments. - Dave --Boundary_(ID_YeqJ5GjQU34PMJZ5Hxdh2w) Content-type: text/plain; name=sched.patch Content-transfer-encoding: 7BIT Content-disposition: inline; filename=sched.patch --- ./include/linux-dist/completion.h Sun Dec 8 10:57:47 2002 +++ ./include/linux/completion.h Mon Dec 9 15:11:51 2002 @@ -28,6 +28,7 @@ } extern void FASTCALL(wait_for_completion(struct completion *)); +extern int FASTCALL(wait_timeout(struct completion *, signed long jiffies)); extern void FASTCALL(complete(struct completion *)); extern void FASTCALL(complete_all(struct completion *)); --- ./kernel-dist/ksyms.c Sun Dec 8 10:57:48 2002 +++ ./kernel/ksyms.c Mon Dec 9 15:13:47 2002 @@ -404,7 +404,9 @@ EXPORT_SYMBOL(autoremove_wake_function); /* completion handling */ EXPORT_SYMBOL(wait_for_completion); +EXPORT_SYMBOL(wait_timeout); EXPORT_SYMBOL(complete); +EXPORT_SYMBOL(complete_all); /* The notion of irq probe/assignment is foreign to S/390 */ --- ./kernel-dist/sched.c Sun Dec 8 10:57:48 2002 +++ ./kernel/sched.c Mon Dec 9 15:34:36 2002 @@ -1204,6 +1204,11 @@ void complete_all(struct completion *x) void wait_for_completion(struct completion *x) { + wait_timeout (x, MAX_SCHEDULE_TIMEOUT); +} + +int wait_timeout(struct completion *x, signed long timeout_jiffies) +{ might_sleep(); spin_lock_irq(&x->wait.lock); if (!x->done) { @@ -1214,13 +1219,19 @@ void wait_for_completion(struct completi do { __set_current_state(TASK_UNINTERRUPTIBLE); spin_unlock_irq(&x->wait.lock); - schedule(); + timeout_jiffies = schedule_timeout(timeout_jiffies); + if (timeout_jiffies == 0) { + __remove_wait_queue(&x->wait, &wait); + /* caller should wait again */ + return 1; + } spin_lock_irq(&x->wait.lock); } while (!x->done); __remove_wait_queue(&x->wait, &wait); } x->done--; spin_unlock_irq(&x->wait.lock); + return 0; } #define SLEEP_ON_VAR \ --Boundary_(ID_YeqJ5GjQU34PMJZ5Hxdh2w)--