This patch adds system heap to the dma-buf heaps framework.
This allows applications to get a page-allocator backed dma-buf for non-contiguous memory.
This code is an evolution of the Android ION implementation, so thanks to its original authors and maintainters: Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
Cc: Laura Abbott labbott@redhat.com Cc: Benjamin Gaignard benjamin.gaignard@linaro.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Liam Mark lmark@codeaurora.org Cc: Pratik Patel pratikp@codeaurora.org Cc: Brian Starkey Brian.Starkey@arm.com Cc: Vincent Donnefort Vincent.Donnefort@arm.com Cc: Sudipto Paul Sudipto.Paul@arm.com Cc: Andrew F. Davis afd@ti.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: Hridya Valsaraju hridya@google.com Cc: dri-devel@lists.freedesktop.org Reviewed-by: Benjamin Gaignard benjamin.gaignard@linaro.org Signed-off-by: John Stultz john.stultz@linaro.org --- v2: * Switch allocate to return dmabuf fd * Simplify init code * Checkpatch fixups * Droped dead system-contig code v3: * Whitespace fixups from Benjamin * Make sure we're zeroing the allocated pages (from Liam) * Use PAGE_ALIGN() consistently (suggested by Brian) * Fold in new registration style from Andrew * Avoid needless dynamic allocation of sys_heap (suggested by Christoph) * Minor cleanups * Folded in changes from Andrew to use simplified page list from the heap helpers v4: * Optimization to allocate pages in chunks, similar to old pagepool code * Use fd_flags when creating dmabuf fd (Suggested by Benjamin) v5: * Back out large order page allocations (was leaking memory, as the page array didn't properly track order size) v6: * Minor whitespace change suggested by Brian * Remove unused variable v7: * Use newly lower-cased init_heap_helper_buffer helper * Add system heap DOS avoidance suggested by Laura from ION code * Use new dmabuf export helper v8: * Make struct dma_heap_ops consts (suggested by Christoph) * Get rid of needless struct system_heap (suggested by Christoph) * Condense dma_heap_buffer and heap_helper_buffer (suggested by Christoph) * Add forgotten include file to fix build issue on x86 --- drivers/dma-buf/Kconfig | 2 + drivers/dma-buf/heaps/Kconfig | 6 ++ drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/system_heap.c | 122 ++++++++++++++++++++++++++++ 4 files changed, 131 insertions(+) create mode 100644 drivers/dma-buf/heaps/Kconfig create mode 100644 drivers/dma-buf/heaps/system_heap.c
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index 162e24e1e429..657ce743abda 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -48,4 +48,6 @@ menuconfig DMABUF_HEAPS allows userspace to use to allocate dma-bufs that can be shared between drivers.
+source "drivers/dma-buf/heaps/Kconfig" + endmenu diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig new file mode 100644 index 000000000000..205052744169 --- /dev/null +++ b/drivers/dma-buf/heaps/Kconfig @@ -0,0 +1,6 @@ +config DMABUF_HEAPS_SYSTEM + bool "DMA-BUF System Heap" + depends on DMABUF_HEAPS + help + Choose this option to enable the system dmabuf heap. The system heap + is backed by pages from the buddy allocator. If in doubt, say Y. diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index de49898112db..d1808eca2581 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0 obj-y += heap-helpers.o +obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c new file mode 100644 index 000000000000..5db4ef9b4afc --- /dev/null +++ b/drivers/dma-buf/heaps/system_heap.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DMABUF System heap exporter + * + * Copyright (C) 2011 Google, Inc. + * Copyright (C) 2019 Linaro Ltd. + */ + +#include <asm/page.h> +#include <linux/dma-buf.h> +#include <linux/dma-mapping.h> +#include <linux/dma-heap.h> +#include <linux/err.h> +#include <linux/highmem.h> +#include <linux/mm.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/sched/signal.h> + +#include "heap-helpers.h" + +struct dma_heap *sys_heap; + +static void system_heap_free(struct heap_helper_buffer *buffer) +{ + pgoff_t pg; + + for (pg = 0; pg < buffer->pagecount; pg++) + __free_page(buffer->pages[pg]); + kfree(buffer->pages); + kfree(buffer); +} + +static int system_heap_allocate(struct dma_heap *heap, + unsigned long len, + unsigned long fd_flags, + unsigned long heap_flags) +{ + struct heap_helper_buffer *helper_buffer; + struct dma_buf *dmabuf; + int ret = -ENOMEM; + pgoff_t pg; + + helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL); + if (!helper_buffer) + return -ENOMEM; + + init_heap_helper_buffer(helper_buffer, system_heap_free); + helper_buffer->flags = heap_flags; + helper_buffer->heap = heap; + helper_buffer->size = len; + + helper_buffer->pagecount = len / PAGE_SIZE; + helper_buffer->pages = kmalloc_array(helper_buffer->pagecount, + sizeof(*helper_buffer->pages), + GFP_KERNEL); + if (!helper_buffer->pages) { + ret = -ENOMEM; + goto err0; + } + + for (pg = 0; pg < helper_buffer->pagecount; pg++) { + /* + * Avoid trying to allocate memory if the process + * has been killed by by SIGKILL + */ + if (fatal_signal_pending(current)) + goto err1; + + helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!helper_buffer->pages[pg]) + goto err1; + } + + /* create the dmabuf */ + dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags); + if (IS_ERR(dmabuf)) { + ret = PTR_ERR(dmabuf); + goto err1; + } + + helper_buffer->dmabuf = dmabuf; + + ret = dma_buf_fd(dmabuf, fd_flags); + if (ret < 0) { + dma_buf_put(dmabuf); + /* just return, as put will call release and that will free */ + return ret; + } + + return ret; + +err1: + while (pg > 0) + __free_page(helper_buffer->pages[--pg]); + kfree(helper_buffer->pages); +err0: + kfree(helper_buffer); + + return -ENOMEM; +} + +static const struct dma_heap_ops system_heap_ops = { + .allocate = system_heap_allocate, +}; + +static int system_heap_create(void) +{ + struct dma_heap_export_info exp_info; + int ret = 0; + + exp_info.name = "system_heap"; + exp_info.ops = &system_heap_ops; + exp_info.priv = NULL; + + sys_heap = dma_heap_add(&exp_info); + if (IS_ERR(sys_heap)) + ret = PTR_ERR(sys_heap); + + return ret; +} +device_initcall(system_heap_create);