From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:38556 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754229Ab0G2Njs (ORCPT ); Thu, 29 Jul 2010 09:39:48 -0400 Received: by pzk26 with SMTP id 26so91842pzk.19 for ; Thu, 29 Jul 2010 06:39:48 -0700 (PDT) Subject: Re: [PATCH v2]videobuf_dma_sg: a new implementation for mmap From: "Figo.zhang" To: Mauro Carvalho Chehab Cc: Mauro Carvalho Chehab , linux-media , Laurent Pinchart In-Reply-To: <1280322504.13781.7.camel@localhost.localdomain> References: <1280233300.2628.8.camel@localhost.localdomain> <1280321854.13781.6.camel@localhost.localdomain> <1280322504.13781.7.camel@localhost.localdomain> Content-Type: text/plain; charset="UTF-8" Date: Thu, 29 Jul 2010 21:38:17 +0800 Message-ID: <1280410697.13781.22.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: hi Laurent, would you like to test this patch? btw, why i send the patch , patchwork websit display a part of my patch? https://patchwork.kernel.org/patch/114760/ Best, Figo.zhang On Wed, 2010-07-28 at 21:08 +0800, Figo.zhang wrote: > a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping > when it encounter page fault at video_vm_ops->fault(). > > a new implementation for mmap, it translate the vmalloc to page at > video_vm_ops->fault(). > > in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will > alloc memory by vmalloc_32(). > > Signed-off-by: Figo.zhang > --- > drivers/media/video/videobuf-dma-sg.c | 51 > +++++++++++++++++++++++++++------ > 1 files changed, 42 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/video/videobuf-dma-sg.c > b/drivers/media/video/videobuf-dma-sg.c > index 8359e6b..767483d 100644 > --- a/drivers/media/video/videobuf-dma-sg.c > +++ b/drivers/media/video/videobuf-dma-sg.c > @@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct > videobuf_dmabuf *dma, int direction, > dprintk(1, "init kernel [%d pages]\n", nr_pages); > > dma->direction = direction; > - dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT); > - if (NULL == dma->vmalloc) { > - dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); > - return -ENOMEM; > + if (!dma->vmalloc) > + dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT); > + if (NULL == dma->vmalloc) { > + dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages); > + return -ENOMEM; > } > > dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n", > @@ -397,16 +398,48 @@ static void videobuf_vm_close(struct > vm_area_struct *vma) > */ > static int videobuf_vm_fault(struct vm_area_struct *vma, struct > vm_fault *vmf) > { > - struct page *page; > + struct page *page = NULL; > + struct videobuf_mapping *map = vma->vm_private_data; > + struct videobuf_queue *q = map->q; > + struct videobuf_dma_sg_memory *mem = NULL; > + > + unsigned long offset; > + unsigned long page_nr; > + int first; > > dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n", > (unsigned long)vmf->virtual_address, > vma->vm_start, vma->vm_end); > > - page = alloc_page(GFP_USER | __GFP_DMA32); > - if (!page) > - return VM_FAULT_OOM; > - clear_user_highpage(page, (unsigned long)vmf->virtual_address); > + mutex_lock(&q->vb_lock); > + > + offset = (unsigned long)vmf->virtual_address - vma->vm_start; > + page_nr = offset >> PAGE_SHIFT; > + > + for (first = 0; first < VIDEO_MAX_FRAME; first++) { > + if (NULL == q->bufs[first]) > + continue; > + > + MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); > + > + if (q->bufs[first]->map == map) > + break; > + } > + > + mem = q->bufs[first]->priv; > + if (!mem) > + return VM_FAULT_SIGBUS; > + if (!mem->dma.vmalloc) { > + mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size)); > + if (NULL == mem->dma.vmalloc) { > + dprintk(1, "%s: vmalloc_32() failed\n", __func__); > + return VM_FAULT_OOM; > + } > + } else > + page = vmalloc_to_page(mem->dma.vmalloc+ > + (offset & (~PAGE_MASK))); > + mutex_unlock(&q->vb_lock); > + > vmf->page = page; > > return 0; >