From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 08C033E7BC5; Thu, 4 Jun 2026 08:42:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562580; cv=none; b=pPHm3zIkQbhvawyJAw+YASV7kSoaopR4sShASeiMDnpHNN7+df6f56FvQDml86AR/Sc77GYsY3riZIU6fbgMqx9NkdzC7Rbhep20ZoabPgQ+3YsjyUFBTpPXO+w+rXQU8cnTiEVOZiW30eooU7bDEHKmCe8HKu2yptxjnAoIi1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562580; c=relaxed/simple; bh=g/wtgfIecl6o8kwHeLkDvFzrvI6n8z3n5Cw9liWsHGo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hv/k16on6i0zdDBOu3sJa6+IhIFCZv8oU4PsczDWICH/mI9AoxMytKuOql+eDywaeIgLKGeW2AXtGiFHKa6DjcOc0G4CnvokxmDL+UYS3+SZRLjkylnosIzeAhKwQMB4Yy43db5sy3g1k6LYpsNW2nBf4liddruF0hKWifhPVEc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kPwkUEOk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kPwkUEOk" 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> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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