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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,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 6CFDFC432C2 for ; Wed, 25 Sep 2019 13:23:32 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4DDEE21D7C for ; Wed, 25 Sep 2019 13:23:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4DDEE21D7C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 6644CE33; Wed, 25 Sep 2019 13:23:17 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id EFACFE2A for ; Wed, 25 Sep 2019 13:23:13 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id BFF5E8A for ; Wed, 25 Sep 2019 13:23:03 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id AB8DD4A6; Wed, 25 Sep 2019 15:23:01 +0200 (CEST) From: Joerg Roedel To: iommu@lists.linux-foundation.org, Joerg Roedel Subject: [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Date: Wed, 25 Sep 2019 15:22:56 +0200 Message-Id: <20190925132300.3038-3-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190925132300.3038-1-joro@8bytes.org> References: <20190925132300.3038-1-joro@8bytes.org> Cc: Filippo Sironi , jroedel@suse.de X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org From: Joerg Roedel The lock is not necessary because the device table does not contain shared state that needs protection. Locking is only needed on an individual entry basis, and that needs to happen on the iommu_dev_data level. Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path") Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 042854bbc5bc..37a9c04fc728 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -70,7 +70,6 @@ */ #define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38)) -static DEFINE_SPINLOCK(amd_iommu_devtable_lock); static DEFINE_SPINLOCK(pd_bitmap_lock); /* List of all available dev_data structures */ @@ -2080,10 +2079,11 @@ static void do_detach(struct iommu_dev_data *dev_data) static int __attach_device(struct iommu_dev_data *dev_data, struct protection_domain *domain) { + unsigned long flags; int ret; /* lock domain */ - spin_lock(&domain->lock); + spin_lock_irqsave(&domain->lock, flags); ret = -EBUSY; if (dev_data->domain != NULL) @@ -2097,7 +2097,7 @@ static int __attach_device(struct iommu_dev_data *dev_data, out_unlock: /* ready */ - spin_unlock(&domain->lock); + spin_unlock_irqrestore(&domain->lock, flags); return ret; } @@ -2181,7 +2181,6 @@ static int attach_device(struct device *dev, { struct pci_dev *pdev; struct iommu_dev_data *dev_data; - unsigned long flags; int ret; dev_data = get_dev_data(dev); @@ -2209,9 +2208,7 @@ static int attach_device(struct device *dev, } skip_ats_check: - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); ret = __attach_device(dev_data, domain); - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); /* * We might boot into a crash-kernel here. The crashed kernel @@ -2231,14 +2228,15 @@ static int attach_device(struct device *dev, static void __detach_device(struct iommu_dev_data *dev_data) { struct protection_domain *domain; + unsigned long flags; domain = dev_data->domain; - spin_lock(&domain->lock); + spin_lock_irqsave(&domain->lock, flags); do_detach(dev_data); - spin_unlock(&domain->lock); + spin_unlock_irqrestore(&domain->lock, flags); } /* @@ -2248,7 +2246,6 @@ static void detach_device(struct device *dev) { struct protection_domain *domain; struct iommu_dev_data *dev_data; - unsigned long flags; dev_data = get_dev_data(dev); domain = dev_data->domain; @@ -2262,10 +2259,7 @@ static void detach_device(struct device *dev) if (WARN_ON(!dev_data->domain)) return; - /* lock device table */ - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); __detach_device(dev_data); - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); if (!dev_is_pci(dev)) return; @@ -2910,9 +2904,6 @@ int __init amd_iommu_init_dma_ops(void) static void cleanup_domain(struct protection_domain *domain) { struct iommu_dev_data *entry; - unsigned long flags; - - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); while (!list_empty(&domain->dev_list)) { entry = list_first_entry(&domain->dev_list, @@ -2920,8 +2911,6 @@ static void cleanup_domain(struct protection_domain *domain) BUG_ON(!entry->domain); __detach_device(entry); } - - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); } static void protection_domain_free(struct protection_domain *domain) -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu