From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E80DC3A589 for ; Tue, 20 Aug 2019 22:33:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B2F822DA7 for ; Tue, 20 Aug 2019 22:33:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="hi64jpA4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731203AbfHTWd5 (ORCPT ); Tue, 20 Aug 2019 18:33:57 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:36986 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730981AbfHTWdC (ORCPT ); Tue, 20 Aug 2019 18:33:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Zi03AHwAAmTpHDRqyNtFRC9dOLO7obHgqglUc3WJ1ZI=; b=hi64jpA4/bQxmlT+QeTiHbpikf ZZ3FtkRnyItYX1/hSxi94LL2ClLiSZ8cvPpuf3PpWtpjl2QAU4VDnONviPirKDmiZu/se7UKwA4zf JccXPoWQive1KWTqh1s0krVogn/3y+eYfEhMlrIr0TG1QcTZxPwiqD4vkZaPSBf4cPP3I6ltDtFtp vqTet0qD45vhzP96E2E/xkKLLOjyUS3J8iL5Y2zdJ/mpwJ2bjc7rS2SSHu2aqbC1P8HUalGMfYeCA OYfScgfcRRfQIzFRLPIdGVEN2wDKCwtoqAYTZYZymIzNxEzNXT8yoU5lYfyfZ/vEG8LnqFYEqPmoF SqYCM+gw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i0CgY-0005qr-DJ; Tue, 20 Aug 2019 22:33:02 +0000 From: Matthew Wilcox To: netdev@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" Subject: [PATCH 14/38] tap: Convert minor_idr to XArray Date: Tue, 20 Aug 2019 15:32:35 -0700 Message-Id: <20190820223259.22348-15-willy@infradead.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190820223259.22348-1-willy@infradead.org> References: <20190820223259.22348-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: "Matthew Wilcox (Oracle)" The minor_lock can be removed as the XArray contains its own spinlock. I suspect the GFP_ATOMIC allocation could be GFP_KERNEL, but I couldn't prove it. Signed-off-by: Matthew Wilcox (Oracle) --- drivers/net/tap.c | 32 +++++++++++++------------------- 1 file changed, 13 insertions(+), 19 deletions(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index dd614c2cd994..81b06a21d96c 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -14,9 +14,9 @@ #include #include #include -#include #include #include +#include #include #include @@ -106,8 +106,7 @@ static LIST_HEAD(major_list); struct major_info { struct rcu_head rcu; dev_t major; - struct idr minor_idr; - spinlock_t minor_lock; + struct xarray tap_devs; const char *device_name; struct list_head next; }; @@ -414,19 +413,16 @@ int tap_get_minor(dev_t major, struct tap_dev *tap) goto unlock; } - spin_lock(&tap_major->minor_lock); - retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC); - if (retval >= 0) { - tap->minor = retval; - } else if (retval == -ENOSPC) { + retval = xa_alloc(&tap_major->tap_devs, &tap->minor, tap, + XA_LIMIT(0, TAP_NUM_DEVS), GFP_ATOMIC); + if (retval == -EBUSY) { netdev_err(tap->dev, "Too many tap devices\n"); retval = -EINVAL; } - spin_unlock(&tap_major->minor_lock); unlock: rcu_read_unlock(); - return retval < 0 ? retval : 0; + return retval; } EXPORT_SYMBOL_GPL(tap_get_minor); @@ -440,12 +436,12 @@ void tap_free_minor(dev_t major, struct tap_dev *tap) goto unlock; } - spin_lock(&tap_major->minor_lock); + xa_lock(&tap_major->tap_devs); if (tap->minor) { - idr_remove(&tap_major->minor_idr, tap->minor); + __xa_erase(&tap_major->tap_devs, tap->minor); tap->minor = 0; } - spin_unlock(&tap_major->minor_lock); + xa_unlock(&tap_major->tap_devs); unlock: rcu_read_unlock(); @@ -465,13 +461,13 @@ static struct tap_dev *dev_get_by_tap_file(int major, int minor) goto unlock; } - spin_lock(&tap_major->minor_lock); - tap = idr_find(&tap_major->minor_idr, minor); + xa_lock(&tap_major->tap_devs); + tap = xa_load(&tap_major->tap_devs, minor); if (tap) { dev = tap->dev; dev_hold(dev); } - spin_unlock(&tap_major->minor_lock); + xa_unlock(&tap_major->tap_devs); unlock: rcu_read_unlock(); @@ -1322,8 +1318,7 @@ static int tap_list_add(dev_t major, const char *device_name) tap_major->major = MAJOR(major); - idr_init(&tap_major->minor_idr); - spin_lock_init(&tap_major->minor_lock); + xa_init_flags(&tap_major->tap_devs, XA_FLAGS_ALLOC1); tap_major->device_name = device_name; @@ -1369,7 +1364,6 @@ void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev) unregister_chrdev_region(major, TAP_NUM_DEVS); list_for_each_entry_safe(tap_major, tmp, &major_list, next) { if (tap_major->major == MAJOR(major)) { - idr_destroy(&tap_major->minor_idr); list_del_rcu(&tap_major->next); kfree_rcu(tap_major, rcu); } -- 2.23.0.rc1