videobuf-vmalloc.c: Fix hack of postponing mmap on remap failure

In videobuf-vmalloc.c remap_vmalloc_range is failing when applications are
trying to mmap buffers immediately after reqbuf.  It fails because the vmalloc
area isn't setup until the first QBUF when drivers call iolock.

This patch introduces mmap_setup to the qtype_ops and it is called in
__videobuf_mmap_setup if the buffer type is mmap.  In the case of vmalloc
buffers this calls iolock, and sets the state to idle.

I don't think this is needed for dma-sg buffers and it defaults to a no-op for
everything but vmalloc.

Signed-off-by: Brandon Philips <bphilips@suse.de>

---
 linux/drivers/media/video/videobuf-core.c    |   29 +++++++-----------
 linux/drivers/media/video/videobuf-vmalloc.c |   43 +++++++++++++--------------
 linux/include/media/videobuf-core.h          |    3 +
 3 files changed, 35 insertions(+), 40 deletions(-)

1 files changed, 21 insertions, 22 deletions

diff --git a/linux/drivers/media/video/videobuf-vmalloc.c b/linux/drivers/media/video/videobuf-vmalloc.c
index 3ce1c92fc..3bc7308af 100644
--- a/linux/drivers/media/video/videobuf-vmalloc.c
+++ b/linux/drivers/media/video/videobuf-vmalloc.c
@@ -152,21 +152,26 @@ static int __videobuf_iolock (struct videobuf_queue* q,
 				(unsigned long)mem->vmalloc,
 				pages << PAGE_SHIFT);
 
-	/* It seems that some kernel versions need to do remap *after*
-	   the mmap() call
-	 */
-	if (mem->vma) {
-		int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
-		kfree(mem->vma);
-		mem->vma=NULL;
-		if (retval<0) {
-			dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
-				mem->vmalloc,retval);
-			return retval;
+	return 0;
+}
+
+static int __videobuf_mmap_setup(struct videobuf_queue *q,
+			      struct videobuf_buffer *vb)
+{
+	int retval = 0;
+	BUG_ON(vb->memory != V4L2_MEMORY_MMAP);
+	if (vb->state == VIDEOBUF_NEEDS_INIT) {
+		/* bsize == size since the buffer needs to be large enough to
+		 * hold an entire frame, not the case in the read case for
+		 * example*/
+		vb->size = vb->bsize;
+		retval = __videobuf_iolock(q, vb, NULL);
+		if (!retval) {
+			/* Don't IOLOCK later */
+			vb->state = VIDEOBUF_IDLE;
 		}
 	}
-
-	return 0;
+	return retval;
 }
 
 static int __videobuf_sync(struct videobuf_queue *q,
@@ -239,15 +244,8 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 	/* Try to remap memory */
 	retval=remap_vmalloc_range(vma, mem->vmalloc,0);
 	if (retval<0) {
-		dprintk(1,"mmap: postponing remap_vmalloc_range\n");
-
-		mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
-		if (!mem->vma) {
-			kfree(map);
-			q->bufs[first]->map=NULL;
-			return -ENOMEM;
-		}
-		memcpy(mem->vma,vma,sizeof(*vma));
+		dprintk(1, "mmap: failed to remap_vmalloc_range\n");
+		return -EINVAL;
 	}
 
 	dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
@@ -315,6 +313,7 @@ static struct videobuf_qtype_ops qops = {
 	.alloc        = __videobuf_alloc,
 	.iolock       = __videobuf_iolock,
 	.sync         = __videobuf_sync,
+	.mmap_setup   = __videobuf_mmap_setup,
 	.mmap_free    = __videobuf_mmap_free,
 	.mmap_mapper  = __videobuf_mmap_mapper,
 	.video_copy_to_user = __videobuf_copy_to_user,