From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760604Ab3BICpt (ORCPT ); Fri, 8 Feb 2013 21:45:49 -0500 Received: from mail-da0-f47.google.com ([209.85.210.47]:40840 "EHLO mail-da0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757769Ab3BICpp (ORCPT ); Fri, 8 Feb 2013 21:45:45 -0500 From: Michel Lespinasse To: linux-kernel@vger.kernel.org, anton@samba.org, hpa@zytor.com, mingo@kernel.org, arjan@linux.intel.com, a.p.zijlstra@chello.nl, torvalds@linux-foundation.org, alex.shi@intel.com, yuanhan.liu@linux.intel.com, dhowells@redhat.com, akpm@linux-foundation.org, tglx@linutronix.de Subject: [PATCH 1/4] rwsem: make the waiter type an enumeration rather than a bitmask Date: Fri, 8 Feb 2013 18:45:34 -0800 Message-Id: <1360377937-16297-2-git-send-email-walken@google.com> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1360377937-16297-1-git-send-email-walken@google.com> References: <1360377937-16297-1-git-send-email-walken@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are not planning to add some new waiter flags, so we can convert the waiter type into an enumeration. Background: David Howells suggested I do this back when I tried adding a new waiter type for unfair readers. However, I believe the cleanup applies regardless of that use case. Signed-off-by: Michel Lespinasse --- lib/rwsem.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/lib/rwsem.c b/lib/rwsem.c index 8337e1b9bb8d..4a6ff093a433 100644 --- a/lib/rwsem.c +++ b/lib/rwsem.c @@ -28,12 +28,15 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, EXPORT_SYMBOL(__init_rwsem); +enum rwsem_waiter_type { + RWSEM_WAITING_FOR_WRITE, + RWSEM_WAITING_FOR_READ +}; + struct rwsem_waiter { struct list_head list; struct task_struct *task; - unsigned int flags; -#define RWSEM_WAITING_FOR_READ 0x00000001 -#define RWSEM_WAITING_FOR_WRITE 0x00000002 + enum rwsem_waiter_type type; }; /* Wake types for __rwsem_do_wake(). Note that RWSEM_WAKE_NO_ACTIVE and @@ -63,7 +66,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) signed long oldcount, woken, loop, adjustment; waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list); - if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE)) + if (waiter->type != RWSEM_WAITING_FOR_WRITE) goto readers_only; if (wake_type == RWSEM_WAKE_READ_OWNED) @@ -132,10 +135,10 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) waiter = list_entry(waiter->list.next, struct rwsem_waiter, list); - } while (waiter->flags & RWSEM_WAITING_FOR_READ); + } while (waiter->type != RWSEM_WAITING_FOR_WRITE); adjustment = woken * RWSEM_ACTIVE_READ_BIAS; - if (waiter->flags & RWSEM_WAITING_FOR_READ) + if (waiter->type != RWSEM_WAITING_FOR_WRITE) /* hit end of list above */ adjustment -= RWSEM_WAITING_BIAS; @@ -171,7 +174,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) */ static struct rw_semaphore __sched * rwsem_down_failed_common(struct rw_semaphore *sem, - unsigned int flags, signed long adjustment) + enum rwsem_waiter_type type, signed long adjustment) { struct rwsem_waiter waiter; struct task_struct *tsk = current; @@ -182,7 +185,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, /* set up my own style of waitqueue */ raw_spin_lock_irq(&sem->wait_lock); waiter.task = tsk; - waiter.flags = flags; + waiter.type = type; get_task_struct(tsk); if (list_empty(&sem->wait_list)) -- 1.8.1