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 972D8CD3427 for ; Tue, 5 May 2026 14:05:44 +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=WQqTzTa1rUYumJAQvlc+xaV9V/kpVDcB193BDO6HPQA=; b=cLBgSQYtNwv8fLoLimhJauFytE jpu/wVxoFd1NMnbZHCfF8VCPfKiRI0Fxo4kylHN7Qg3e16lF+tbBkNpvG4Cb5wIcJMOUFNRi2ElZE SgzuO19EH049o+4Y39bbMds5mGruE1WCAs00lsdoKr4b6Y3dwwio41GblQrM0IqxPp8e6o43hg2Q0 H0CxtwLtztoImBuv40ibHbU3pQPS+IGbz0ZoKr+GQMOJ32udEl2ii882cI+dV1Qrr0Cz7oRRTLp8B Z11OvOmdEv9+3DVT1W/FCksIlvsi5+0OhK1AQs7JRJup+UxGnbRd5fYpiPXNSZj2ZHoU0Je0umrCu kmduWUOw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wKGP6-0000000GR9X-3PaF; Tue, 05 May 2026 14:05:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wKGP4-0000000GR7f-0uX2; Tue, 05 May 2026 14:05:39 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1787924C0; Tue, 5 May 2026 07:05:31 -0700 (PDT) Received: from e120398-lin.trondheim.arm.com (e120398-lin.trondheim.arm.com [10.42.46.160]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 770E33F763; Tue, 5 May 2026 07:05:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777989936; bh=knenjS6icqSk3YRJhYDzdkIS/YGlcoD/AJp0MB+GY40=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cW8emmly/iWCkM4Zgb9M2QLXsBVbQTUQISQA8G9vSVGTr6pfllLsjuzA0hQyI7W1W dNR1TgB+qSzwQOZcaJYjQnVP0oULO8NgArKEd8VRGzt8Y+ZHJAiellnat15kTvAun6 UODcQQwfFPRRbZWB5eWC2x19OixZ3PCB42MD4Z0I= From: Ketil Johnsen To: David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Jonathan Corbet , Shuah Khan , Sumit Semwal , Benjamin Gaignard , Brian Starkey , John Stultz , "T.J. Mercier" , =?UTF-8?q?Christian=20K=C3=B6nig?= , Boris Brezillon , Steven Price , Liviu Dudau , Daniel Almeida , Alice Ryhl , Matthias Brugger , AngeloGioacchino Del Regno Cc: dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Yong Wu , Yunfei Dong , Florent Tomasin , Ketil Johnsen Subject: [PATCH 2/8] dma-heap: Provide accessors so that in-kernel drivers can allocate dmabufs from specific heaps Date: Tue, 5 May 2026 16:05:08 +0200 Message-ID: <20260505140516.1372388-3-ketil.johnsen@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260505140516.1372388-1-ketil.johnsen@arm.com> References: <20260505140516.1372388-1-ketil.johnsen@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260505_070538_336254_3E95535D X-CRM114-Status: GOOD ( 21.12 ) 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 From: John Stultz This allows drivers who don't want to create their own DMA-BUF exporter to be able to allocate DMA-BUFs directly from existing DMA-BUF Heaps. There is some concern that the premise of DMA-BUF heaps is that userland knows better about what type of heap memory is needed for a pipeline, so it would likely be best for drivers to import and fill DMA-BUFs allocated by userland instead of allocating one themselves, but this is still up for debate. Signed-off-by: John Stultz Signed-off-by: T.J. Mercier Signed-off-by: Yong Wu [Yong: Fix the checkpatch alignment warning] Signed-off-by: Yunfei Dong Signed-off-by: Florent Tomasin [Florent: Rebase] Signed-off-by: Ketil Johnsen [Ketil: Rebase] --- drivers/dma-buf/dma-heap.c | 80 ++++++++++++++++++++++++++++++-------- include/linux/dma-heap.h | 6 +++ 2 files changed, 70 insertions(+), 16 deletions(-) diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 9fd365ddbd517..854d40d789ff2 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -57,12 +57,24 @@ module_param(mem_accounting, bool, 0444); MODULE_PARM_DESC(mem_accounting, "Enable cgroup-based memory accounting for dma-buf heap allocations (default=false)."); -static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, - u32 fd_flags, - u64 heap_flags) +/** + * dma_heap_buffer_alloc - Allocate dma-buf from a dma_heap + * @heap: DMA-Heap to allocate from + * @len: size to allocate in bytes + * @fd_flags: flags to set on returned dma-buf fd + * @heap_flags: flags to pass to the dma heap + * + * This is for internal dma-buf allocations only. Free returned buffers with dma_buf_put(). + */ +struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, + u32 fd_flags, + u64 heap_flags) { - struct dma_buf *dmabuf; - int fd; + if (fd_flags & ~DMA_HEAP_VALID_FD_FLAGS) + return ERR_PTR(-EINVAL); + + if (heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS) + return ERR_PTR(-EINVAL); /* * Allocations from all heaps have to begin @@ -70,9 +82,20 @@ static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, */ len = PAGE_ALIGN(len); if (!len) - return -EINVAL; + return ERR_PTR(-EINVAL); + + return heap->ops->allocate(heap, len, fd_flags, heap_flags); +} +EXPORT_SYMBOL_NS_GPL(dma_heap_buffer_alloc, "DMA_BUF_HEAP"); - dmabuf = heap->ops->allocate(heap, len, fd_flags, heap_flags); +static int dma_heap_bufferfd_alloc(struct dma_heap *heap, size_t len, + u32 fd_flags, + u64 heap_flags) +{ + struct dma_buf *dmabuf; + int fd; + + dmabuf = dma_heap_buffer_alloc(heap, len, fd_flags, heap_flags); if (IS_ERR(dmabuf)) return PTR_ERR(dmabuf); @@ -110,15 +133,9 @@ static long dma_heap_ioctl_allocate(struct file *file, void *data) if (heap_allocation->fd) return -EINVAL; - if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS) - return -EINVAL; - - if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS) - return -EINVAL; - - fd = dma_heap_buffer_alloc(heap, heap_allocation->len, - heap_allocation->fd_flags, - heap_allocation->heap_flags); + fd = dma_heap_bufferfd_alloc(heap, heap_allocation->len, + heap_allocation->fd_flags, + heap_allocation->heap_flags); if (fd < 0) return fd; @@ -317,6 +334,36 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) } EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP"); +/** + * dma_heap_find - get the heap registered with the specified name + * @name: Name of the DMA-Heap to find + * + * Returns: + * The DMA-Heap with the provided name. + * + * NOTE: DMA-Heaps returned from this function MUST be released using + * dma_heap_put() when the user is done to enable the heap to be unloaded. + */ +struct dma_heap *dma_heap_find(const char *name) +{ + struct dma_heap *h; + + mutex_lock(&heap_list_lock); + list_for_each_entry(h, &heap_list, list) { + if (!kref_get_unless_zero(&h->refcount)) + continue; + + if (!strcmp(h->name, name)) { + mutex_unlock(&heap_list_lock); + return h; + } + dma_heap_put(h); + } + mutex_unlock(&heap_list_lock); + return NULL; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_find, "DMA_BUF_HEAP"); + static void dma_heap_release(struct kref *ref) { struct dma_heap *heap = container_of(ref, struct dma_heap, refcount); @@ -341,6 +388,7 @@ void dma_heap_put(struct dma_heap *heap) { kref_put(&heap->refcount, dma_heap_release); } +EXPORT_SYMBOL_NS_GPL(dma_heap_put, "DMA_BUF_HEAP"); static char *dma_heap_devnode(const struct device *dev, umode_t *mode) { diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index ff57741700f5f..c3351f8a1f8cf 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -46,8 +46,14 @@ const char *dma_heap_get_name(struct dma_heap *heap); struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info); +struct dma_heap *dma_heap_find(const char *name); + void dma_heap_put(struct dma_heap *heap); +struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, + u32 fd_flags, + u64 heap_flags); + extern bool mem_accounting; #endif /* _DMA_HEAPS_H */ -- 2.43.0