From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753457AbcKUGQd (ORCPT ); Mon, 21 Nov 2016 01:16:33 -0500 Received: from mail-pf0-f182.google.com ([209.85.192.182]:33897 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750744AbcKUGQc (ORCPT ); Mon, 21 Nov 2016 01:16:32 -0500 From: Binoy Jayan To: Doug Ledford , Sean Hefty , Sagi Grimberg , Hal Rosenstock , Leon Romanovsky , Sagi Grimberg , Bart Van Assche , Nicholas Bellinger , Jenny Derzhavetz , Ira Weiny , Steve Wise , Mark Bloch , Tatyana E Nikolova , Matan Barak , Lijun Ou , "Wei Hu(Xavier)" Cc: Faisal Latif , Mustafa Ismail , Mark Brown , Arnd Bergmann , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, target-devel@vger.kernel.org, Binoy Jayan Subject: [PATCH v5 2/9] IB/core: Replace semaphore sm_sem with an atomic wait Date: Mon, 21 Nov 2016 11:38:09 +0530 Message-Id: <1479708496-9828-3-git-send-email-binoy.jayan@linaro.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1479708496-9828-1-git-send-email-binoy.jayan@linaro.org> References: <1479708496-9828-1-git-send-email-binoy.jayan@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The semaphore 'sm_sem' is used for an exclusive ownership of the device so model the same as an atomic variable with an associated wait_event. Semaphores are going away in the future. Signed-off-by: Binoy Jayan --- drivers/infiniband/core/user_mad.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 415a318..6101c0a 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -67,6 +67,8 @@ enum { IB_UMAD_MINOR_BASE = 0 }; +#define UMAD_F_CLAIM 0x01 + /* * Our lifetime rules for these structs are the following: * device special file is opened, we take a reference on the @@ -87,7 +89,8 @@ struct ib_umad_port { struct cdev sm_cdev; struct device *sm_dev; - struct semaphore sm_sem; + wait_queue_head_t wq; + unsigned long flags; struct mutex file_mutex; struct list_head file_list; @@ -1030,12 +1033,14 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) port = container_of(inode->i_cdev, struct ib_umad_port, sm_cdev); if (filp->f_flags & O_NONBLOCK) { - if (down_trylock(&port->sm_sem)) { + if (test_and_set_bit(UMAD_F_CLAIM, &port->flags)) { ret = -EAGAIN; goto fail; } } else { - if (down_interruptible(&port->sm_sem)) { + if (wait_event_interruptible(port->wq, + !test_and_set_bit(UMAD_F_CLAIM, + &port->flags))) { ret = -ERESTARTSYS; goto fail; } @@ -1060,7 +1065,8 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) ib_modify_port(port->ib_dev, port->port_num, 0, &props); err_up_sem: - up(&port->sm_sem); + clear_bit(UMAD_F_CLAIM, &port->flags); + wake_up(&port->wq); fail: return ret; @@ -1079,7 +1085,8 @@ static int ib_umad_sm_close(struct inode *inode, struct file *filp) ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props); mutex_unlock(&port->file_mutex); - up(&port->sm_sem); + clear_bit(UMAD_F_CLAIM, &port->flags); + wake_up(&port->wq); kobject_put(&port->umad_dev->kobj); @@ -1177,7 +1184,8 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, port->ib_dev = device; port->port_num = port_num; - sema_init(&port->sm_sem, 1); + init_waitqueue_head(&port->wq); + __clear_bit(UMAD_F_CLAIM, &port->flags); mutex_init(&port->file_mutex); INIT_LIST_HEAD(&port->file_list); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project