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Message-ID: <20110420085908.GA7294@minime.bse>
Date: Wed, 20 Apr 2011 10:59:08 +0200
From: Daniel Glöckner <daniel-gl@....net>
To: Bob Liu <lliubbo@...il.com>
Cc: linux-media@...r.kernel.org, linux-uvc-devel@...ts.berlios.de,
linux-kernel@...r.kernel.org, mchehab@...hat.com,
hverkuil@...all.nl, laurent.pinchart@...asonboard.com,
sakari.ailus@...well.research.nokia.com, martin_rubli@...itech.com,
jarod@...hat.com, tj@...nel.org, arnd@...db.de, fweisbec@...il.com,
agust@...x.de, gregkh@...e.de
Subject: Re: Fwd: [PATCH v2] media: uvc_driver: add NO-MMU arch support
On Wed, Apr 20, 2011 at 02:02:41PM +0800, Bob Liu wrote:
> ---------- Forwarded message ----------
Forwarding broke tabs.
> @@ -445,6 +446,20 @@ int uvc_queue_mmap(struct uvc_video_queue *queue,
> struct vm_area_struct *vma)
> addr += PAGE_SIZE;
> size -= PAGE_SIZE;
> }
> +#else
> + if (i == queue->count ||
> + PAGE_ALIGN(size) != queue->buf_size) {
Why do you need to round up size on nommu?
> + ret = -EINVAL;
> + goto done;
> + }
> +
> + /* documentation/nommu-mmap.txt */
I don't see where Documentation/nommu-mmap.txt provides any information
on the following line(s).
> + vma->vm_flags |= VM_IO | VM_MAYSHARE;
> +
> + addr = (unsigned long)queue->mem + buffer->buf.m.offset;
> + vma->vm_start = addr;
> + vma->vm_end = addr + queue->buf_size;
You don't need to do this here. vm_start and vm_end have already been
modified like this by do_mmap_pgoff after get_unmapped_area had been
called.
> +#endif
>
> vma->vm_ops = &uvc_vm_ops;
> vma->vm_private_data = buffer;
> @@ -489,6 +504,38 @@ done:
> }
>
> /*
> + * Get unmapped area.
> + *
> + * NO-MMU arch need this function to make mmap() work correctly.
> + */
> +unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
> + unsigned long addr, unsigned long len, unsigned long pgoff)
> +{
> + struct uvc_buffer *buffer;
> + unsigned int i;
> + int ret = 0;
ret should be an unsigned long. You later try to store a pointer in
there.
> +
> + mutex_lock(&queue->mutex);
> + for (i = 0; i < queue->count; ++i) {
> + buffer = &queue->buffer[i];
> + if ((buffer->buf.m.offset >> PAGE_SHIFT) == pgoff)
> + break;
> + }
> +
> + if (i == queue->count ||
> + PAGE_ALIGN(len) != queue->buf_size) {
> + ret = -EINVAL;
> + goto done;
> + }
> +
> + addr = (unsigned long)queue->mem + buffer->buf.m.offset;
> + ret = addr;
> +done:
> + mutex_unlock(&queue->mutex);
> + return ret;
> +}
> +
> +/*
> * Enable or disable the video buffers queue.
> *
> * The queue must be enabled before starting video acquisition and must be
> diff --git a/drivers/media/video/uvc/uvc_v4l2.c
> b/drivers/media/video/uvc/uvc_v4l2.c
> index 9005a8d..9efab61 100644
> --- a/drivers/media/video/uvc/uvc_v4l2.c
> +++ b/drivers/media/video/uvc/uvc_v4l2.c
> @@ -1081,6 +1081,18 @@ static unsigned int uvc_v4l2_poll(struct file
> *file, poll_table *wait)
> return uvc_queue_poll(&stream->queue, file, wait);
> }
>
> +static unsigned long uvc_v4l2_get_unmapped_area(struct file *file,
> + unsigned long addr, unsigned long len, unsigned long pgoff,
> + unsigned long flags)
> +{
> + struct uvc_fh *handle = file->private_data;
> + struct uvc_streaming *stream = handle->stream;
> +
> + uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_get_unmapped_area\n");
> +
> + return uvc_queue_get_unmapped_area(&stream->queue, addr, len, pgoff);
> +}
> +
> const struct v4l2_file_operations uvc_fops = {
> .owner = THIS_MODULE,
> .open = uvc_v4l2_open,
> @@ -1089,5 +1101,6 @@ const struct v4l2_file_operations uvc_fops = {
> .read = uvc_v4l2_read,
> .mmap = uvc_v4l2_mmap,
> .poll = uvc_v4l2_poll,
> + .get_unmapped_area = uvc_v4l2_get_unmapped_area,
> };
>
> diff --git a/drivers/media/video/uvc/uvcvideo.h
> b/drivers/media/video/uvc/uvcvideo.h
> index 45f01e7..48a2378 100644
> --- a/drivers/media/video/uvc/uvcvideo.h
> +++ b/drivers/media/video/uvc/uvcvideo.h
> @@ -580,6 +580,12 @@ extern int uvc_queue_mmap(struct uvc_video_queue *queue,
> struct vm_area_struct *vma);
> extern unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
> struct file *file, poll_table *wait);
> +#ifdef CONFIG_MMU
> +#define uvc_queue_get_unmapped_area NULL
> +#else
> +extern unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
> + unsigned long addr, unsigned long len, unsigned long pgoff);
> +#endif
> extern int uvc_queue_allocated(struct uvc_video_queue *queue);
> static inline int uvc_queue_streaming(struct uvc_video_queue *queue)
> {
> diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
Rest looks good.
Did you change anything in the generic code or is this a plain
git revert c29fcff3daafbf46d64a543c1950bbd206ad8c1c
?
Maybe one can unify the mmu and nommu versions of uvc_queue_mmap by using
remap_vmalloc_range but IMHO the nommu versions of the remap_*_range
functions are broken and should only validate if the source and destination
addresses match.
Daniel
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