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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0D006F9B5F6 for ; Wed, 22 Apr 2026 09:29:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Date:Subject:Cc:To:From:Message-ID: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=My6EacjSNjmZHU0CTpNvEYFjVGs69rZoNa95xb2tQH0=; b=V3V/8NE/6z7WMdLd/ZEn1IXh31 m//dxGXHXEO7VmJI2FkFRLGH7islpHQo6pHGKJS+kVRPR5fDjlTGv3OSB6hIaO0SadTgo+M13p4E8 s5WsCIh4c0A2mZjUUkR3HXAKyCuDXhLsZ8+64PXRwTOfDZu1caWgqgl2OSMTCaP6w2BleFjXNGKyz 8BT71WLiecSn7LSQhDtId3pTDt2QY7yg+AoNRI0cCzJadi0WuJeCDS83+Nl3e6illjfKNPzoL39Hr bv7rQ/BL/Ix1iTbQe4WYaL4LQyYpPEmucwGwf6D26JbQ3dZh7uOqwZpQttHLLer3UYMy34cCr2PUb uxAs4YUQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFTtF-00000009qG0-2cje; Wed, 22 Apr 2026 09:29:01 +0000 Received: from out203-205-221-191.mail.qq.com ([203.205.221.191]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFTtC-00000009qFG-3pcm for linux-arm-kernel@lists.infradead.org; Wed, 22 Apr 2026 09:29:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1776850135; bh=My6EacjSNjmZHU0CTpNvEYFjVGs69rZoNa95xb2tQH0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hG1d0IPj/EyGS5LZMAA6yIpL1c8xXk4rWtgLrNGHimeE0qcN5W5sSXpxH5FN5OJn/ BZneeaUHe5uQQqh6S20EqP1eFg8Ixf8DGx+ARanhRTYvsM5DUmolan2RIUUpb+ZEbi xEqg9o3FRJIb49u7ANOxUo7srsCc3Y5WwMsC0n4I= Received: from LAPTOP-LEO.yizhu.local ([61.169.175.90]) by newxmesmtplogicsvrszc56-0.qq.com (NewEsmtp) with SMTP id 735968E0; Wed, 22 Apr 2026 17:28:53 +0800 X-QQ-mid: xmsmtpt1776850133tw656rhmy Message-ID: X-QQ-XMAILINFO: MIoti6gokNxFG89lDdt/Ih6wjJqL2qXZRDgYysB5haN0dSdvhD8KKtT4+mwQ2K s0SsaXzcyN4ptUbs/odxnD+TBA3tSKEMyQ2HInL4H0n9sfmqlbn53bjcJlZM5ad7sjq6+Ev6CxmZ Ozn2c0sXUl5yps02x95b/CrXVubw5B3ZSRrymB+o70of8X9ASlUqUMcZ1aZzX0MWHPR+nvjIv9re wkqC6xFLqlWdOh7mUE90TFnC9IIjTfkCa0fdwNAQKMxD9aamVwUhwbBClWCjiAtrxt8z9zmz3u1N /jauqWukPI7W10c/iu6AQyVrDenlzMIH6VcQKQdAN4WVHQPUm4tiMqwK/pqB1Kc30JDoxVJYrGea qWXEdbidWzLUGiDjU+SureWFBYe8Gj9p5NQ3tcXCVY51ge27/lKos/i02qAWzGvE/hkN3SZ+ZmGL 1qghN10rVbZh/ho2ZV71BmTJ3Ax4sJjA3iBwesCUpjbJ3FthON2vYXzYko9ZWMlJTT0NpQLoU7/w G9XDLDwfPlAUT8TZSRZM8U7opKV9pUo3ESLM0xBBJsrBX6shmxjcQuS2Ufp1h8C1UclZMhWsCrhB xw+G2xs3bUP472D7u2Hq/Hd2NyuDbYbnPnEJ7Hc12prmMeNVUgNPXO3yZj2YJmUCykDBkhRFqHil JB59BcO0jh8sGz7yv6ktx9yYzRjDZFE0ZeyiHXhm/9UBmKmzE/1y/AxsIbmBJ/VXlSz0djroXLCb BjKEg0qbr5FEfRJ9laXtLsqvyuj2grcl0w1xglagmO+x+KnK9lZ7Eu36pgj56Za+IBnTbauJ1SIB lO5fknXIwLaSP4sqjbxIxJzbnLlEH5i/WRkEsqEpWNK5Srjuw+cqe1dvfCegrdaZhSYOUqIvVPrH 1nEHrXab6y3oQoj6CbNlvOQFmX40ZYX5CcGocEmAqrm4MmlHyFiClaepOCkY3rTzpetirijVlzYZ mqzrnZr3zmTx46MfStKCxIgk1r/vFIYgZkjBIZjVQ1tHqeJFSuvMtPoraNpjQx7OWMLmdwvBNO7F lAxPoQlPIikfX/5MVzqxeCFKKUPIYhVdfnCIZCG2SrRpPtRQT5BhT6cMbXxiaDmfl3pRENh068oq mPKgAvYBo3xQq3h21dTAitDGRuQVRWqAbXeNE7WTQi5NnZnKAK9gd78sLeXlNDcOy1rJxm24cX8T Xzbw2r754Bfl2v3k4VP1YTxN+O X-QQ-XMRINFO: NS+P29fieYNwqS3WCnRCOn9D1NpZuCnCRA== From: Leo Jiang To: Will Deacon Cc: Robin Murphy , Joerg Roedel , iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Leo Jiang Subject: [PATCH v2] iommu/arm-smmu-v3: Limit queue allocation retry boundary to PAGE_SIZE Date: Wed, 22 Apr 2026 17:28:52 +0800 X-OQ-MSGID: <20260422092852.1824220-1-leo.jiang1224@foxmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260422_022859_290307_6AABEE4E X-CRM114-Status: GOOD ( 11.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In arm_smmu_init_one_queue(), the driver attempts to allocate the largest supported queue and retries by halving the size on failure. Currently, the retry logic allows the allocation to fall below PAGE_SIZE if the PAGE_SIZE attempt fails. While dmam_alloc_coherent() can theoretically return allocations smaller than a page in certain configurations, it is preferable to limit the retry boundary to PAGE_SIZE for SMMUv3 queues to align with the original design intent. This patch ensures the retry loop terminates when qsz reaches PAGE_SIZE, per the feedback from the maintainer. Signed-off-by: Leo Jiang --- v2: - Use real name "Leo Jiang". - Remove code comments as suggested by Will. - Limit the queue allocation retry boundary to PAGE_SIZE drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index e8d7dbe495f0..4a0b15b1d4d2 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -4418,7 +4418,7 @@ int arm_smmu_init_one_queue(struct arm_smmu_device *smmu, qsz = ((1 << q->llq.max_n_shift) * dwords) << 3; q->base = dmam_alloc_coherent(smmu->dev, qsz, &q->base_dma, GFP_KERNEL); - if (q->base || qsz < PAGE_SIZE) + if (q->base || qsz <= PAGE_SIZE) break; q->llq.max_n_shift--; -- 2.34.1