Hi Marek,
On Friday 19 November 2010 16:55:40 Marek Szyprowski wrote:
> From: Pawel Osciak <p.osciak@xxxxxxxxxxx>
>
> Add an implementation of contiguous virtual memory allocator and handling
> routines for videobuf2, implemented on top of vmalloc()/vfree() calls.
>
> Signed-off-by: Pawel Osciak <p.osciak@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> CC: Pawel Osciak <pawel@xxxxxxxxxx>
> ---
> drivers/media/video/Kconfig | 5 +
> drivers/media/video/Makefile | 1 +
> drivers/media/video/videobuf2-vmalloc.c | 177
> +++++++++++++++++++++++++++++++ include/media/videobuf2-vmalloc.h |
> 21 ++++
> 4 files changed, 204 insertions(+), 0 deletions(-)
> create mode 100644 drivers/media/video/videobuf2-vmalloc.c
> create mode 100644 include/media/videobuf2-vmalloc.h
>
> diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
> index 83ce858..9351423 100644
> --- a/drivers/media/video/Kconfig
> +++ b/drivers/media/video/Kconfig
> @@ -55,6 +55,11 @@ config VIDEOBUF2_CORE
> config VIDEOBUF2_MEMOPS
> tristate
>
> +config VIDEOBUF2_VMALLOC
> + select VIDEOBUF2_CORE
> + select VIDEOBUF2_MEMOPS
> + tristate
> +
> #
> # Multimedia Video device configuration
> #
> diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
> index a97a2a0..538bee9 100644
> --- a/drivers/media/video/Makefile
> +++ b/drivers/media/video/Makefile
> @@ -116,6 +116,7 @@ obj-$(CONFIG_VIDEO_BTCX) += btcx-risc.o
>
> obj-$(CONFIG_VIDEOBUF2_CORE) += videobuf2-core.o
> obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o
> +obj-$(CONFIG_VIDEOBUF2_VMALLOC) += videobuf2-vmalloc.o
>
> obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
>
> diff --git a/drivers/media/video/videobuf2-vmalloc.c
> b/drivers/media/video/videobuf2-vmalloc.c new file mode 100644
> index 0000000..3310900
> --- /dev/null
> +++ b/drivers/media/video/videobuf2-vmalloc.c
> @@ -0,0 +1,177 @@
> +/*
> + * videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
> + *
> + * Copyright (C) 2010 Samsung Electronics
> + *
> + * Author: Pawel Osciak <p.osciak@xxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/mm.h>
> +#include <linux/slab.h>
> +#include <linux/vmalloc.h>
> +
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-memops.h>
> +
> +struct vb2_vmalloc_conf {
> + struct vb2_alloc_ctx alloc_ctx;
> +};
> +
> +struct vb2_vmalloc_buf {
> + void *vaddr;
> + unsigned long size;
> + unsigned int refcount;
> +};
> +
> +static void *vb2_vmalloc_alloc(const struct vb2_alloc_ctx *alloc_ctx,
> + unsigned long size)
> +{
> + struct vb2_vmalloc_buf *buf;
> +
> + buf = kzalloc(sizeof *buf, GFP_KERNEL);
> + if (!buf)
> + return NULL;
> +
> + buf->size = size;
> + buf->vaddr = vmalloc_user(buf->size);
Some drivers might need vmalloc_32_user instead.
> + if (!buf->vaddr) {
> + printk(KERN_ERR "vmalloc of size %ld failed\n", buf->size);
> + kfree(buf);
> + return NULL;
> + }
> +
> + buf->refcount++;
> + printk(KERN_DEBUG "Allocated vmalloc buffer of size %ld at vaddr=%p\n",
> + buf->size, buf->vaddr);
> +
> + return buf;
> +}
> +
> +static void vb2_vmalloc_put(void *buf_priv)
> +{
> + struct vb2_vmalloc_buf *buf = buf_priv;
> +
> + buf->refcount--;
> +
> + if (0 == buf->refcount) {
> + printk(KERN_DEBUG "%s: Freeing vmalloc mem at vaddr=%p\n",
> + __func__, buf->vaddr);
> + vfree(buf->vaddr);
> + kfree(buf);
> + }
> +}
> +
> +static void *vb2_vmalloc_vaddr(void *buf_priv)
> +{
> + struct vb2_vmalloc_buf *buf = buf_priv;
> +
> + BUG_ON(!buf);
> +
> + if (!buf->vaddr) {
> + printk(KERN_ERR "Address of an unallocated "
> + "plane requested\n");
Can this happen under normal circumstances, or is it a driver bug ? In the
later case a WARN_ON might be better.
> + return NULL;
> + }
> +
> + return buf->vaddr;
> +}
> +
> +static unsigned int vb2_vmalloc_num_users(void *buf_priv)
> +{
> + struct vb2_vmalloc_buf *buf = buf_priv;
> +
> + return buf->refcount;
> +}
> +
> +/* TODO generalize and extract to core as much as possible */
I agree with the TODO :-) This part doesn't seem very clean, and
vm_open/vm_close handling certainly needs documentation.
> +static void vb2_vmalloc_vm_open(struct vm_area_struct *vma)
> +{
> + struct vb2_vmalloc_buf *buf = vma->vm_private_data;
> +
> + printk(KERN_DEBUG "%s vmalloc_priv: %p, refcount: %d, "
> + "vma: %08lx-%08lx\n", __func__, buf, buf->refcount,
> + vma->vm_start, vma->vm_end);
> +
> + buf->refcount++;
> +}
> +
> +static void vb2_vmalloc_vm_close(struct vm_area_struct *vma)
> +{
> + struct vb2_vmalloc_buf *buf = vma->vm_private_data;
> +
> + printk(KERN_DEBUG "%s vmalloc_priv: %p, refcount: %d, "
> + "vma: %08lx-%08lx\n", __func__, buf, buf->refcount,
> + vma->vm_start, vma->vm_end);
> +
> + vb2_vmalloc_put(buf);
> +}
> +
> +static const struct vm_operations_struct vb2_vmalloc_vm_ops = {
> + .open = vb2_vmalloc_vm_open,
> + .close = vb2_vmalloc_vm_close,
> +};
> +
> +static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
> +{
> + struct vb2_vmalloc_buf *buf = buf_priv;
> + int ret;
> +
> + if (!buf) {
> + printk(KERN_ERR "No memory to map\n");
> + return -EINVAL;
> + }
I think you should test that the VMA size is equal to (or smaller than) the
buffer size. That could be done in the core.
> + ret = remap_vmalloc_range(vma, buf->vaddr, 0);
> + if (ret) {
> + printk(KERN_ERR "Remapping vmalloc memory, error: %d\n", ret);
> + return ret;
> + }
> +
> + vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
VM_RESERVED is set by remap_vmalloc_range(). What is VM_DONTEXPAND for ?
> + vma->vm_private_data = buf;
> + vma->vm_ops = &vb2_vmalloc_vm_ops;
> +
> + vb2_vmalloc_vm_open(vma);
> +
> + return 0;
> +}
> +
> +static const struct vb2_mem_ops vb2_vmalloc_ops = {
> + .alloc = vb2_vmalloc_alloc,
> + .put = vb2_vmalloc_put,
> + .vaddr = vb2_vmalloc_vaddr,
> + .mmap = vb2_vmalloc_mmap,
> + .num_users = vb2_vmalloc_num_users,
> +};
> +
> +struct vb2_alloc_ctx *vb2_vmalloc_init(void)
> +{
> + struct vb2_vmalloc_conf *conf;
> +
> + conf = kzalloc(sizeof *conf, GFP_KERNEL);
> + if (!conf)
> + return ERR_PTR(-ENOMEM);
> +
> + conf->alloc_ctx.mem_ops = &vb2_vmalloc_ops;
> +
> + return &conf->alloc_ctx;
> +}
> +EXPORT_SYMBOL_GPL(vb2_vmalloc_init);
> +
> +void vb2_vmalloc_cleanup(struct vb2_alloc_ctx *alloc_ctx)
> +{
> + struct vb2_vmalloc_conf *conf =
> + container_of(alloc_ctx, struct vb2_vmalloc_conf, alloc_ctx);
> +
> + kfree(conf);
> +}
> +EXPORT_SYMBOL_GPL(vb2_vmalloc_cleanup);
> +
> +MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
> +MODULE_AUTHOR("Pawel Osciak");
> +MODULE_LICENSE("GPL");
> diff --git a/include/media/videobuf2-vmalloc.h
> b/include/media/videobuf2-vmalloc.h new file mode 100644
> index 0000000..0e7c303
> --- /dev/null
> +++ b/include/media/videobuf2-vmalloc.h
> @@ -0,0 +1,21 @@
> +/*
> + * videobuf2-vmalloc.h - vmalloc memory allocator for videobuf2
> + *
> + * Copyright (C) 2010 Samsung Electronics
> + *
> + * Author: Pawel Osciak <p.osciak@xxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation.
> + */
> +
> +#ifndef _MEDIA_VIDEOBUF2_VMALLOC_H
> +#define _MEDIA_VIDEOBUF2_VMALLOC_H
> +
> +#include <media/videobuf2-core.h>
> +
> +struct vb2_alloc_ctx *vb2_vmalloc_init(void);
> +void vb2_vmalloc_cleanup(struct vb2_alloc_ctx *alloc_ctx);
> +
> +#endif
--
Regards,
Laurent Pinchart
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