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 61B35CD6E57 for ; Thu, 4 Jun 2026 08:43:06 +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:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5WeykkaLRY84/gMTdzzVPplQJSrHkGjIEUjp2FUb45E=; b=yi7OfmVd9KiylQXZuQ7WIZ8+PJ gVkJqGOcf/vS/oIouqP1LAktNuAG+hbAOBfXpanIBT3C3uvSgxbiPVwjnJbjGQcqgge0Mts0Wq+pd azBAZDooPbfpQaGq57VoteX5HntuxlB6W+qR+QsraGx2OMua5WkCu7XKxMNd0Rgh/PvFWdrXVHp2q RkuSNp9z+NrMtMEk2lyHioNYP7GqZtd4nHoQi05Er2ylfzUD6IU7hfl0C6kHaBOy7kOzT0OVzaamb hBPmnBPGANwXukOg0lYVfQqS0jZY1SZqLKWVsthtFFZtzakEoPEymbicAtzT1yf6gR8v3xMxx1ztf +UzN6adw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wV3fI-0000000GPTz-1ZhM; Thu, 04 Jun 2026 08:43:00 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wV3fH-0000000GPTH-2D58 for linux-arm-kernel@lists.infradead.org; Thu, 04 Jun 2026 08:42:59 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id F1FC1601D6; Thu, 4 Jun 2026 08:42:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 415181F00898; Thu, 4 Jun 2026 08:42:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780562578; bh=5WeykkaLRY84/gMTdzzVPplQJSrHkGjIEUjp2FUb45E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kPwkUEOk1WgnrF0lOV0PcG8AQaiVhngfx/W0TVtjGwpDNk1Baj72OsUUlUxaxIdxt GCMc3uO9dZ0y+4DmEajexLfTCy0njgJdDKWFY9hNA6cHq5Mr0VzYb075IVKnz09ylZ mhURdS/1AaP9I7PUlOb/20/S5Qac8flUQ4Ku/7TmUPowi2LXf/qpYsGBY67dQRdlSr BJppQVtzWfkLsFwBGMpoLv4SBMYJXdg+a+LtnxbzH90+JUMUfoODtJ8bcesSA/7/Q7 ep7tfYzuBiwuLbY57SGVqmXpr1NYNfK8KsDo5ZI/oY1hIt+e9hbCAbrkFpKYImCFdg JlZGreIpvlfMA== From: "Aneesh Kumar K.V (Arm)" To: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev Cc: "Aneesh Kumar K.V (Arm)" , Robin Murphy , Marek Szyprowski , Will Deacon , Marc Zyngier , Steven Price , Suzuki K Poulose , Catalin Marinas , Jiri Pirko , Jason Gunthorpe , Mostafa Saleh , Petr Tesarik , Alexey Kardashevskiy , Dan Williams , Xu Yilun , linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , x86@kernel.org, Michael Kelley Subject: [PATCH v6 18/20] dma: free atomic pool pages by physical address Date: Thu, 4 Jun 2026 14:09:57 +0530 Message-ID: <20260604083959.1265923-19-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org> References: <20260604083959.1265923-1-aneesh.kumar@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 dma_direct_alloc_pages() may satisfy atomic allocations from the coherent atomic pools. The pool allocation is keyed by the virtual address stored in the gen_pool, but the pages API returns only the backing struct page. On architectures with CONFIG_DMA_DIRECT_REMAP, atomic pool chunks are added to the gen_pool using their remapped virtual address. dma_direct_free_pages() reconstructs a linear-map address with page_address(page) and passes that to dma_free_from_pool(). That address does not match the gen_pool virtual range, so the pool lookup can fail and the code can fall through to freeing a pool-owned page through the normal page allocator path. Add a page-based pool free helper that looks up the owning pool chunk by physical address, translates it back to the gen_pool virtual address, and frees that address to the pool. Use it from dma_direct_free_pages() while keeping the existing virtual-address helper for coherent allocation frees. Tested-by: Michael Kelley Tested-by: Mostafa Saleh Signed-off-by: Aneesh Kumar K.V (Arm) --- include/linux/dma-map-ops.h | 1 + kernel/dma/direct.c | 4 +-- kernel/dma/pool.c | 54 +++++++++++++++++++++++++++++++++++++ 3 files changed, 57 insertions(+), 2 deletions(-) diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 696b2c3a2305..8be059e69935 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -215,6 +215,7 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size, void **cpu_addr, gfp_t flags, unsigned long attrs, bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)); bool dma_free_from_pool(struct device *dev, void *start, size_t size); +bool dma_free_from_pool_page(struct device *dev, struct page *page, size_t size); int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start, dma_addr_t dma_start, u64 size); diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index e0ab9ff3f1d6..58f7ea1be963 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -488,9 +488,9 @@ void dma_direct_free_pages(struct device *dev, size_t size, */ bool mark_mem_encrypted = force_dma_unencrypted(dev); - /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ + /* If page is not from an atomic pool, dma_free_from_pool_page() fails */ if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && - dma_free_from_pool(dev, vaddr, size)) + dma_free_from_pool_page(dev, page, size)) return; phys = page_to_phys(page); diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index e7df8d279e75..43b8101d860f 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -356,3 +356,57 @@ bool dma_free_from_pool(struct device *dev, void *start, size_t size) return false; } + +struct dma_pool_phys_match { + phys_addr_t phys; + size_t size; + unsigned long addr; + bool found; +}; + +static void dma_pool_find_phys(struct gen_pool *pool, struct gen_pool_chunk *chunk, + void *data) +{ + struct dma_pool_phys_match *match = data; + phys_addr_t end = match->phys + match->size - 1; + phys_addr_t chunk_end; + + if (match->found) + return; + + chunk_end = chunk->phys_addr + (chunk->end_addr - chunk->start_addr); + if (match->phys < chunk->phys_addr || end > chunk_end) + return; + + match->addr = chunk->start_addr + (match->phys - chunk->phys_addr); + match->found = true; +} + +static bool dma_free_from_pool_phys(struct dma_gen_pool *dma_pool, phys_addr_t phys, + size_t size) +{ + struct dma_pool_phys_match match = { + .phys = phys, + .size = size, + }; + + gen_pool_for_each_chunk(dma_pool->pool, dma_pool_find_phys, &match); + if (!match.found) + return false; + + gen_pool_free(dma_pool->pool, match.addr, size); + return true; +} + +bool dma_free_from_pool_page(struct device *dev, struct page *page, size_t size) +{ + struct dma_gen_pool *dma_pool = NULL; + phys_addr_t phys = page_to_phys(page); + + while ((dma_pool = dma_guess_pool(dma_pool, 0))) { + if (dma_free_from_pool_phys(dma_pool, phys, size)) + return true; + } + + return false; +} -- 2.43.0