From patchwork Thu Apr 14 13:06:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 561778 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69D9DC46467 for ; Thu, 14 Apr 2022 13:43:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244695AbiDNNma (ORCPT ); Thu, 14 Apr 2022 09:42:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241302AbiDNNdK (ORCPT ); Thu, 14 Apr 2022 09:33:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 286FB22BF5; Thu, 14 Apr 2022 06:30:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D3182B82968; Thu, 14 Apr 2022 13:30:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40516C385A1; Thu, 14 Apr 2022 13:30:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649943043; bh=VwFEHE+CO5lRFmJFYl4MnPfpyZ8Welh346AwcCF/UoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z9qmaLK5NNxQSLggWZw0JFQIa6ad+3zOw/vmi7FfuHaXPTHVRdm5gmsu74MueRQ4O RDJvJTbxsOwNhY7NQ9s+eEuaCwL/BZG67i/RJWXHld9+CH2U5iVBalzo/XhsrvIXu3 G+OiZpViSfus5fjruqjB8pEGdxXVGj/oRL3KL+Dg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yunfei Wang , Robin Murphy , Miles Chen , Joerg Roedel Subject: [PATCH 5.4 015/475] iommu/iova: Improve 32-bit free space estimate Date: Thu, 14 Apr 2022 15:06:40 +0200 Message-Id: <20220414110855.580257654@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110855.141582785@linuxfoundation.org> References: <20220414110855.141582785@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Robin Murphy commit 5b61343b50590fb04a3f6be2cdc4868091757262 upstream. For various reasons based on the allocator behaviour and typical use-cases at the time, when the max32_alloc_size optimisation was introduced it seemed reasonable to couple the reset of the tracked size to the update of cached32_node upon freeing a relevant IOVA. However, since subsequent optimisations focused on helping genuine 32-bit devices make best use of even more limited address spaces, it is now a lot more likely for cached32_node to be anywhere in a "full" 32-bit address space, and as such more likely for space to become available from IOVAs below that node being freed. At this point, the short-cut in __cached_rbnode_delete_update() really doesn't hold up any more, and we need to fix the logic to reliably provide the expected behaviour. We still want cached32_node to only move upwards, but we should reset the allocation size if *any* 32-bit space has become available. Reported-by: Yunfei Wang Signed-off-by: Robin Murphy Reviewed-by: Miles Chen Link: https://lore.kernel.org/r/033815732d83ca73b13c11485ac39336f15c3b40.1646318408.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel Cc: Miles Chen Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/iova.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -138,10 +138,11 @@ __cached_rbnode_delete_update(struct iov cached_iova = rb_entry(iovad->cached32_node, struct iova, node); if (free == cached_iova || (free->pfn_hi < iovad->dma_32bit_pfn && - free->pfn_lo >= cached_iova->pfn_lo)) { + free->pfn_lo >= cached_iova->pfn_lo)) iovad->cached32_node = rb_next(&free->node); + + if (free->pfn_lo < iovad->dma_32bit_pfn) iovad->max32_alloc_size = iovad->dma_32bit_pfn; - } cached_iova = rb_entry(iovad->cached_node, struct iova, node); if (free->pfn_lo >= cached_iova->pfn_lo)