media: videobuf-dma-contig: use dma_mmap_coherent

dma_alloc_coherent does not return a physical address, but a DMA address,
which might be remapped or have an offset.  Passing the DMA address to
vm_iomap_memory is thus broken.

Use the proper dma_mmap_coherent helper instead, and stop passing
__GFP_COMP to dma_alloc_coherent, as the memory management inside the
DMA allocator is hidden from the callers and does not require it.

With this the gfp_t argument to __videobuf_dc_alloc can be removed and
hard coded to GFP_KERNEL.

Fixes: a8f3c203e19b ("[media] videobuf-dma-contig: add cache support")
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c
index 52312ce..f2c4393 100644 (file)
--- a/drivers/media/v4l2-core/videobuf-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf-dma-contig.c
@@ -36,12 +36,11 @@ struct videobuf_dma_contig_memory {
 
 static int __videobuf_dc_alloc(struct device *dev,
                               struct videobuf_dma_contig_memory *mem,
-                              unsigned long size, gfp_t flags)
+                              unsigned long size)
 {
        mem->size = size;
-       mem->vaddr = dma_alloc_coherent(dev, mem->size,
-                                       &mem->dma_handle, flags);
-
+       mem->vaddr = dma_alloc_coherent(dev, mem->size, &mem->dma_handle,
+                                       GFP_KERNEL);
        if (!mem->vaddr) {
                dev_err(dev, "memory alloc size %ld failed\n", mem->size);
                return -ENOMEM;
@@ -258,8 +257,7 @@ static int __videobuf_iolock(struct videobuf_queue *q,
                        return videobuf_dma_contig_user_get(mem, vb);
 
                /* allocate memory for the read() method */
-               if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
-                                       GFP_KERNEL))
+               if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size)))
                        return -ENOMEM;
                break;
        case V4L2_MEMORY_OVERLAY:
@@ -295,22 +293,18 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
        BUG_ON(!mem);
        MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 
-       if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
-                               GFP_KERNEL | __GFP_COMP))
+       if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize)))
                goto error;
 
-       /* Try to remap memory */
-       vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
        /* the "vm_pgoff" is just used in v4l2 to find the
         * corresponding buffer data structure which is allocated
         * earlier and it does not mean the offset from the physical
         * buffer start address as usual. So set it to 0 to pass
-        * the sanity check in vm_iomap_memory().
+        * the sanity check in dma_mmap_coherent().
         */
        vma->vm_pgoff = 0;
-
-       retval = vm_iomap_memory(vma, mem->dma_handle, mem->size);
+       retval = dma_mmap_coherent(q->dev, vma, mem->vaddr, mem->dma_handle,
+                                  mem->size);
        if (retval) {
                dev_err(q->dev, "mmap: remap failed with error %d. ",
                        retval);