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Message-Id: <20190814220011.26934-7-robdclark@gmail.com>
Date: Wed, 14 Aug 2019 15:00:01 -0700
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: Christoph Hellwig <hch@....de>, Rob Clark <robdclark@...omium.org>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Emil Velikov <emil.velikov@...labora.com>,
Sean Paul <sean@...rly.run>,
Chris Wilson <chris@...is-wilson.co.uk>,
Imre Deak <imre.deak@...el.com>,
Eric Biggers <ebiggers@...gle.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 6/6] drm/vgem: fix cache synchronization on arm/arm64 (take two)
From: Rob Clark <robdclark@...omium.org>
drm_cflush_pages() is no-op on arm/arm64. But instead we can use
arch_sync API.
Fixes failures with vgem_test.
Signed-off-by: Rob Clark <robdclark@...omium.org>
---
drivers/gpu/drm/vgem/vgem_drv.c | 145 +++++++++++++++++++++-----------
1 file changed, 98 insertions(+), 47 deletions(-)
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index 11a8f99ba18c..4493abdba134 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -34,6 +34,7 @@
#include <linux/ramfs.h>
#include <linux/shmem_fs.h>
#include <linux/dma-buf.h>
+#include <linux/dma-noncoherent.h>
#include "vgem_drv.h"
#define DRIVER_NAME "vgem"
@@ -47,10 +48,16 @@ static struct vgem_device {
struct platform_device *platform;
} *vgem_device;
+static void sync_and_unpin(struct drm_vgem_gem_object *bo);
+static struct page **pin_and_sync(struct drm_vgem_gem_object *bo);
+
static void vgem_gem_free_object(struct drm_gem_object *obj)
{
struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
+ if (!obj->import_attach)
+ sync_and_unpin(vgem_obj);
+
kvfree(vgem_obj->pages);
mutex_destroy(&vgem_obj->pages_lock);
@@ -78,40 +85,15 @@ static vm_fault_t vgem_gem_fault(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
mutex_lock(&obj->pages_lock);
+ if (!obj->pages)
+ pin_and_sync(obj);
if (obj->pages) {
get_page(obj->pages[page_offset]);
vmf->page = obj->pages[page_offset];
ret = 0;
}
mutex_unlock(&obj->pages_lock);
- if (ret) {
- struct page *page;
-
- page = shmem_read_mapping_page(
- file_inode(obj->base.filp)->i_mapping,
- page_offset);
- if (!IS_ERR(page)) {
- vmf->page = page;
- ret = 0;
- } else switch (PTR_ERR(page)) {
- case -ENOSPC:
- case -ENOMEM:
- ret = VM_FAULT_OOM;
- break;
- case -EBUSY:
- ret = VM_FAULT_RETRY;
- break;
- case -EFAULT:
- case -EINVAL:
- ret = VM_FAULT_SIGBUS;
- break;
- default:
- WARN_ON(PTR_ERR(page));
- ret = VM_FAULT_SIGBUS;
- break;
- }
- }
return ret;
}
@@ -277,32 +259,107 @@ static const struct file_operations vgem_driver_fops = {
.release = drm_release,
};
-static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
+/* Called under pages_lock, except in free path (where it can't race): */
+static void sync_and_unpin(struct drm_vgem_gem_object *bo)
{
- mutex_lock(&bo->pages_lock);
- if (bo->pages_pin_count++ == 0) {
- struct page **pages;
-
- pages = drm_gem_get_pages(&bo->base);
- if (IS_ERR(pages)) {
- bo->pages_pin_count--;
- mutex_unlock(&bo->pages_lock);
- return pages;
+ struct device *dev = bo->base.dev->dev;
+
+ if (bo->table) {
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(bo->table->sgl, sg, bo->table->nents, i) {
+ arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length,
+ DMA_BIDIRECTIONAL);
}
- bo->pages = pages;
+ sg_free_table(bo->table);
+ kfree(bo->table);
+ bo->table = NULL;
+ }
+
+ if (bo->pages) {
+ drm_gem_put_pages(&bo->base, bo->pages, true, true);
+ bo->pages = NULL;
+ }
+}
+
+static struct page **pin_and_sync(struct drm_vgem_gem_object *bo)
+{
+ struct device *dev = bo->base.dev->dev;
+ int npages = bo->base.size >> PAGE_SHIFT;
+ struct page **pages;
+ struct sg_table *sgt;
+ struct scatterlist *sg;
+ int i;
+
+ WARN_ON(!mutex_is_locked(&bo->pages_lock));
+
+ pages = drm_gem_get_pages(&bo->base);
+ if (IS_ERR(pages)) {
+ bo->pages_pin_count--;
+ mutex_unlock(&bo->pages_lock);
+ return pages;
+ }
+
+ sgt = drm_prime_pages_to_sg(pages, npages);
+ if (IS_ERR(sgt)) {
+ dev_err(dev, "failed to allocate sgt: %ld\n",
+ PTR_ERR(bo->table));
+ drm_gem_put_pages(&bo->base, pages, false, false);
+ mutex_unlock(&bo->pages_lock);
+ return ERR_CAST(bo->table);
+ }
+
+ /*
+ * Flush the object from the CPU cache so that importers
+ * can rely on coherent indirect access via the exported
+ * dma-address.
+ */
+ for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+ arch_sync_dma_for_device(dev, sg_phys(sg), sg->length,
+ DMA_BIDIRECTIONAL);
+ }
+
+#if defined(CONFIG_X86)
+ /* x86 doesn't have arch_sync_dma_*() */
+ drm_clflush_pages(pages, npages);
+#endif
+
+ bo->pages = pages;
+ bo->table = sgt;
+
+ return pages;
+}
+
+static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
+{
+ struct page **pages;
+
+ mutex_lock(&bo->pages_lock);
+ if (bo->pages_pin_count++ == 0 && !bo->pages) {
+ pages = pin_and_sync(bo);
+ } else {
+ WARN_ON(!bo->pages);
+ pages = bo->pages;
}
mutex_unlock(&bo->pages_lock);
- return bo->pages;
+ return pages;
}
static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)
{
+ /*
+ * We shouldn't hit this for imported bo's.. in the import
+ * case we don't own the scatter-table
+ */
+ WARN_ON(bo->base.import_attach);
+
mutex_lock(&bo->pages_lock);
if (--bo->pages_pin_count == 0) {
- drm_gem_put_pages(&bo->base, bo->pages, true, true);
- bo->pages = NULL;
+ WARN_ON(!bo->table);
+ sync_and_unpin(bo);
}
mutex_unlock(&bo->pages_lock);
}
@@ -310,18 +367,12 @@ static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)
static int vgem_prime_pin(struct drm_gem_object *obj)
{
struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
- long n_pages = obj->size >> PAGE_SHIFT;
struct page **pages;
pages = vgem_pin_pages(bo);
if (IS_ERR(pages))
return PTR_ERR(pages);
- /* Flush the object from the CPU cache so that importers can rely
- * on coherent indirect access via the exported dma-address.
- */
- drm_clflush_pages(pages, n_pages);
-
return 0;
}
--
2.21.0
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