We need dmabuf specific pread() callback utilizing dma-buf API,
otherwise GEM_PREAD IOCTL will no longer work with dma-buf backed
(i.e., PRIME imported) objects on hardware with no mappable aperture.
Signed-off-by: Janusz Krzysztofik <janusz.krzyszto...@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospu...@intel.com>
Cc: Michal Wajdeczko <michal.wajdec...@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 55 ++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 93eea1031c82..207dbf044296 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -248,6 +248,60 @@ static void i915_gem_object_put_pages_dmabuf(struct
drm_i915_gem_object *obj,
DMA_BIDIRECTIONAL);
}
+static int i915_gem_object_pread_dmabuf(struct drm_i915_gem_object *obj,
+ const struct drm_i915_gem_pread *args)
+{
+ struct dma_buf *dmabuf = obj->base.import_attach->dmabuf;
+ void __user *user_data = u64_to_user_ptr(args->data_ptr);
+ struct file *file = dmabuf->file;
+ const struct file_operations *fop = file->f_op;
+ void __force *vaddr;
+ int ret;
+
+ if (fop->read) {
+ loff_t offset = args->offset;
+
+ /*
+ * fop->read() is supposed to call dma_buf_begin_cpu_access()
+ * if O_SYNC flag is set, avoid calling it twice
+ */
+ if (!(file->f_flags & O_SYNC)) {
+ ret = dma_buf_begin_cpu_access(dmabuf, DMA_FROM_DEVICE);
+ if (ret)
+ return ret;
+ }
+
+ ret = fop->read(file, user_data, args->size, &offset);
+
+ if (!(file->f_flags & O_SYNC))
+ dma_buf_end_cpu_access(dmabuf, DMA_FROM_DEVICE);
+
+ if (!ret)
+ return 0;
+ }
+
+ /* dma-buf file .read() not supported or failed, try dma_buf_vmap() */
+ ret = dma_buf_begin_cpu_access(dmabuf, DMA_FROM_DEVICE);
+ if (ret)
+ return ret;
+
+ vaddr = dma_buf_vmap(dmabuf);
+ if (!vaddr)
+ goto out_err;
+
+ ret = copy_to_user(user_data, vaddr + args->offset, args->size);
+ dma_buf_vunmap(dmabuf, vaddr);
+ if (!ret)
+ goto out_end;
+
+out_err:
+ /* fall back to GTT mapping */
+ ret = -ENODEV;
+out_end:
+ dma_buf_end_cpu_access(dmabuf, DMA_FROM_DEVICE);
+ return ret;
+}
+
static int i915_gem_object_pwrite_dmabuf(struct drm_i915_gem_object *obj,
const struct drm_i915_gem_pwrite *args)
{
@@ -305,6 +359,7 @@ static int i915_gem_object_pwrite_dmabuf(struct
drm_i915_gem_object *obj,
static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
.get_pages = i915_gem_object_get_pages_dmabuf,
.put_pages = i915_gem_object_put_pages_dmabuf,
+ .pread = i915_gem_object_pread_dmabuf,
.pwrite = i915_gem_object_pwrite_dmabuf,
};
--
2.21.0
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