Hello, On Thursday, November 25, 2010 11:07 AM Hans Verkuil wrote:
> On Friday, November 19, 2010 16:55:40 Marek Szyprowski wrote: > > From: Pawel Osciak <[email protected]> > > > > 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 <[email protected]> > > Signed-off-by: Kyungmin Park <[email protected]> > > Signed-off-by: Marek Szyprowski <[email protected]> > > CC: Pawel Osciak <[email protected]> > > --- > > 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 <[email protected]> > > + * > > + * 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); > > + 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) { > > I think I would feel happier if refcount was of type atomic_t and you would > use > the atomic decrease-and-test operation here. I know that this is almost > certainly > called with some lock, but still... Yes, it is called with mm_sem taken in all cases. Maybe a comment in the source will be enough to indicate that this variable does not need to be atomic_t type? I can change it to atomic_t if this is really required anyway. <snip> Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
