From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752794AbdDJG7L (ORCPT ); Mon, 10 Apr 2017 02:59:11 -0400 Received: from mail-qk0-f194.google.com ([209.85.220.194]:33701 "EHLO mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442AbdDJG7K (ORCPT ); Mon, 10 Apr 2017 02:59:10 -0400 Message-ID: <58eb2d3c.e43aed0a.e6c99.eed5@mx.google.com> X-Google-Original-Message-ID: <20170410065858.GA18451@> Date: Mon, 10 Apr 2017 12:28:59 +0530 From: Varsha Rao To: Arnd Bergmann , Greg Kroah-Hartman , Matthew Wilcox Cc: linux-kernel@vger.kernel.org Subject: [PATCH 1/2] drivers: char: Replace bit operation functions with IDA allocator. References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Replace bit operation functions with IDA allocator functions. As IDA allocation is simpler, faster, more space efficient and it generates small integer IDs which can be used as minor device numbers. Signed-off-by: Varsha Rao --- drivers/char/misc.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index c9cd1ea..5786281 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -60,7 +60,7 @@ static DEFINE_MUTEX(misc_mtx); * Assigned numbers, used for dynamic minors */ #define DYNAMIC_MINORS 64 /* like dynamic majors */ -static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS); +static DEFINE_IDA(misc_minors_ida); #ifdef CONFIG_PROC_FS static void *misc_seq_start(struct seq_file *seq, loff_t *pos) @@ -193,14 +193,18 @@ int misc_register(struct miscdevice *misc) mutex_lock(&misc_mtx); if (is_dynamic) { - int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS); + int i = ida_simple_get(&misc_minors_ida, 0, + DYNAMIC_MINORS, GFP_KERNEL); if (i >= DYNAMIC_MINORS) { err = -EBUSY; goto out; - } + } else if (i < 0) { + err = i; + goto out; + } else { misc->minor = DYNAMIC_MINORS - i - 1; - set_bit(i, misc_minors); + } } else { struct miscdevice *c; @@ -222,7 +226,7 @@ int misc_register(struct miscdevice *misc) int i = DYNAMIC_MINORS - misc->minor - 1; if (i < DYNAMIC_MINORS && i >= 0) - clear_bit(i, misc_minors); + ida_simple_remove(&misc_minors_ida, i); misc->minor = MISC_DYNAMIC_MINOR; } err = PTR_ERR(misc->this_device); @@ -258,7 +262,7 @@ void misc_deregister(struct miscdevice *misc) list_del(&misc->list); device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor)); if (i < DYNAMIC_MINORS && i >= 0) - clear_bit(i, misc_minors); + ida_simple_remove(&misc_minors_ida, i); mutex_unlock(&misc_mtx); } -- 2.9.3