Reuse/abuse the pagepool code from the network code to speed
up allocation performance.

This is similar to the ION pagepool usage, but tries to
utilize generic code instead of a custom implementation.

Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: Sumit Semwal <sumit.sem...@linaro.org>
Cc: Liam Mark <lm...@codeaurora.org>
Cc: Chris Goldsworthy <cgold...@codeaurora.org>
Cc: Laura Abbott <labb...@kernel.org>
Cc: Brian Starkey <brian.star...@arm.com>
Cc: Hridya Valsaraju <hri...@google.com>
Cc: Suren Baghdasaryan <sur...@google.com>
Cc: Sandeep Patil <sspa...@google.com>
Cc: Daniel Mentz <danielme...@google.com>
Cc: Ørjan Eide <orjan.e...@arm.com>
Cc: Robin Murphy <robin.mur...@arm.com>
Cc: Ezequiel Garcia <ezequ...@collabora.com>
Cc: Simon Ser <cont...@emersion.fr>
Cc: James Jones <jajo...@nvidia.com>
Cc: linux-me...@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stu...@linaro.org>
---
v2:
* Fix build issue caused by selecting PAGE_POOL w/o NET
  as Reported-by: kernel test robot <l...@intel.com>
v3:
* Simplify the page zeroing logic a bit by using kmap_atomic
  instead of vmap as suggested by Daniel Mentz
---
 drivers/dma-buf/heaps/Kconfig       |  2 ++
 drivers/dma-buf/heaps/system_heap.c | 52 ++++++++++++++++++++++++++---
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index f7aef8bc7119..45c7d277448b 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -4,6 +4,8 @@ config DMABUF_HEAPS_DEFERRED_FREE
 config DMABUF_HEAPS_SYSTEM
        bool "DMA-BUF System Heap"
        depends on DMABUF_HEAPS
+       select NET
+       select PAGE_POOL
        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/system_heap.c 
b/drivers/dma-buf/heaps/system_heap.c
index 17e0e9a68baf..2addb6d832e0 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -20,6 +20,7 @@
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <net/page_pool.h>
 
 static struct dma_heap *sys_heap;
 
@@ -53,6 +54,7 @@ static gfp_t order_flags[] = {HIGH_ORDER_GFP, LOW_ORDER_GFP, 
LOW_ORDER_GFP};
  */
 static const unsigned int orders[] = {8, 4, 0};
 #define NUM_ORDERS ARRAY_SIZE(orders)
+struct page_pool *pools[NUM_ORDERS];
 
 static struct sg_table *dup_sg_table(struct sg_table *table)
 {
@@ -281,18 +283,43 @@ static void system_heap_vunmap(struct dma_buf *dmabuf, 
struct dma_buf_map *map)
        dma_buf_map_clear(map);
 }
 
+static int system_heap_zero_buffer(struct system_heap_buffer *buffer)
+{
+       struct sg_table *sgt = &buffer->sg_table;
+       struct sg_page_iter piter;
+       struct page *p;
+       void *vaddr;
+       int ret = 0;
+
+       for_each_sgtable_page(sgt, &piter, 0) {
+               p = sg_page_iter_page(&piter);
+               vaddr = kmap_atomic(p);
+               memset(vaddr, 0, PAGE_SIZE);
+               kunmap_atomic(vaddr);
+       }
+
+       return ret;
+}
+
 static void system_heap_dma_buf_release(struct dma_buf *dmabuf)
 {
        struct system_heap_buffer *buffer = dmabuf->priv;
        struct sg_table *table;
        struct scatterlist *sg;
-       int i;
+       int i, j;
+
+       /* Zero the buffer pages before adding back to the pool */
+       system_heap_zero_buffer(buffer);
 
        table = &buffer->sg_table;
        for_each_sg(table->sgl, sg, table->nents, i) {
                struct page *page = sg_page(sg);
 
-               __free_pages(page, compound_order(page));
+               for (j = 0; j < NUM_ORDERS; j++) {
+                       if (compound_order(page) == orders[j])
+                               break;
+               }
+               page_pool_put_full_page(pools[j], page, false);
        }
        sg_free_table(table);
        kfree(buffer);
@@ -322,8 +349,7 @@ static struct page *alloc_largest_available(unsigned long 
size,
                        continue;
                if (max_order < orders[i])
                        continue;
-
-               page = alloc_pages(order_flags[i], orders[i]);
+               page = page_pool_alloc_pages(pools[i], order_flags[i]);
                if (!page)
                        continue;
                return page;
@@ -428,6 +454,24 @@ static const struct dma_heap_ops system_heap_ops = {
 static int system_heap_create(void)
 {
        struct dma_heap_export_info exp_info;
+       int i;
+
+       for (i = 0; i < NUM_ORDERS; i++) {
+               struct page_pool_params pp;
+
+               memset(&pp, 0, sizeof(pp));
+               pp.order = orders[i];
+               pools[i] = page_pool_create(&pp);
+
+               if (IS_ERR(pools[i])) {
+                       int j;
+
+                       pr_err("%s: page pool creation failed!\n", __func__);
+                       for (j = 0; j < i; j++)
+                               page_pool_destroy(pools[j]);
+                       return PTR_ERR(pools[i]);
+               }
+       }
 
        exp_info.name = "system";
        exp_info.ops = &system_heap_ops;
-- 
2.25.1

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