From 0f6e2825ce916eed882996bb6e9148c13ecebefd Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 13 Jul 2015 11:55:43 -0300 Subject: [media] vb2: Push mmap_sem down to memops Currently vb2 core acquires mmap_sem just around call to __qbuf_userptr(). However since commit f035eb4e976ef5 (videobuf2: fix lockdep warning) it isn't necessary to acquire it so early as we no longer have to drop queue mutex before acquiring mmap_sem. So push acquisition of mmap_sem down into .get_userptr memop so that the semaphore is acquired for a shorter time and it is clearer what it is needed for. Note that we also need mmap_sem in .put_userptr memop since that ends up calling vb2_put_vma() which calls vma->vm_ops->close() which should be called with mmap_sem held. However we didn't hold mmap_sem in some code paths anyway (e.g. when called via vb2_ioctl_reqbufs() -> __vb2_queue_free() -> vb2_dma_sg_put_userptr()) and getting mmap_sem in put_userptr() introduces a lock inversion with queue->mmap_lock in the above mentioned call path. Luckily this whole locking mess will get resolved once we convert videobuf2 core to the new mm helper which avoids the need for mmap_sem in .put_userptr memop altogether. Signed-off-by: Jan Kara Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-vmalloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/media/v4l2-core/videobuf2-vmalloc.c') diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c index 2fe4c27f524a..63bef959623e 100644 --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c @@ -89,7 +89,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, offset = vaddr & ~PAGE_MASK; buf->size = size; - + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, vaddr); if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) { if (vb2_get_contig_userptr(vaddr, size, &vma, &physp)) @@ -121,6 +121,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, if (!buf->vaddr) goto fail_get_user_pages; } + up_read(¤t->mm->mmap_sem); buf->vaddr += offset; return buf; @@ -133,6 +134,7 @@ fail_get_user_pages: kfree(buf->pages); fail_pages_array_alloc: + up_read(¤t->mm->mmap_sem); kfree(buf); return NULL; -- cgit From 5a9e4dec393a2c5a01be6adc63065059b367d532 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 13 Jul 2015 11:55:48 -0300 Subject: [media] media: vb2: Convert vb2_vmalloc_get_userptr() to use frame vector Convert vb2_vmalloc_get_userptr() to use frame vector infrastructure. When we are doing that there's no need to allocate page array and some code can be simplified. Tested-by: Marek Szyprowski Signed-off-by: Jan Kara Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-vmalloc.c | 92 +++++++++++------------------ 1 file changed, 36 insertions(+), 56 deletions(-) (limited to 'drivers/media/v4l2-core/videobuf2-vmalloc.c') diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c index 63bef959623e..ecb8f0c7f025 100644 --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c @@ -23,11 +23,9 @@ struct vb2_vmalloc_buf { void *vaddr; - struct page **pages; - struct vm_area_struct *vma; + struct frame_vector *vec; enum dma_data_direction dma_dir; unsigned long size; - unsigned int n_pages; atomic_t refcount; struct vb2_vmarea_handler handler; struct dma_buf *dbuf; @@ -76,10 +74,8 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, enum dma_data_direction dma_dir) { struct vb2_vmalloc_buf *buf; - unsigned long first, last; - int n_pages, offset; - struct vm_area_struct *vma; - dma_addr_t physp; + struct frame_vector *vec; + int n_pages, offset, i; buf = kzalloc(sizeof(*buf), GFP_KERNEL); if (!buf) @@ -88,53 +84,36 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr, buf->dma_dir = dma_dir; offset = vaddr & ~PAGE_MASK; buf->size = size; - - down_read(¤t->mm->mmap_sem); - vma = find_vma(current->mm, vaddr); - if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) { - if (vb2_get_contig_userptr(vaddr, size, &vma, &physp)) - goto fail_pages_array_alloc; - buf->vma = vma; - buf->vaddr = (__force void *)ioremap_nocache(physp, size); - if (!buf->vaddr) - goto fail_pages_array_alloc; + vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE); + if (IS_ERR(vec)) + goto fail_pfnvec_create; + buf->vec = vec; + n_pages = frame_vector_count(vec); + if (frame_vector_to_pages(vec) < 0) { + unsigned long *nums = frame_vector_pfns(vec); + + /* + * We cannot get page pointers for these pfns. Check memory is + * physically contiguous and use direct mapping. + */ + for (i = 1; i < n_pages; i++) + if (nums[i-1] + 1 != nums[i]) + goto fail_map; + buf->vaddr = (__force void *) + ioremap_nocache(nums[0] << PAGE_SHIFT, size); } else { - first = vaddr >> PAGE_SHIFT; - last = (vaddr + size - 1) >> PAGE_SHIFT; - buf->n_pages = last - first + 1; - buf->pages = kzalloc(buf->n_pages * sizeof(struct page *), - GFP_KERNEL); - if (!buf->pages) - goto fail_pages_array_alloc; - - /* current->mm->mmap_sem is taken by videobuf2 core */ - n_pages = get_user_pages(current, current->mm, - vaddr & PAGE_MASK, buf->n_pages, - dma_dir == DMA_FROM_DEVICE, - 1, /* force */ - buf->pages, NULL); - if (n_pages != buf->n_pages) - goto fail_get_user_pages; - - buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1, + buf->vaddr = vm_map_ram(frame_vector_pages(vec), n_pages, -1, PAGE_KERNEL); - if (!buf->vaddr) - goto fail_get_user_pages; } - up_read(¤t->mm->mmap_sem); + if (!buf->vaddr) + goto fail_map; buf->vaddr += offset; return buf; -fail_get_user_pages: - pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages, - buf->n_pages); - while (--n_pages >= 0) - put_page(buf->pages[n_pages]); - kfree(buf->pages); - -fail_pages_array_alloc: - up_read(¤t->mm->mmap_sem); +fail_map: + vb2_destroy_framevec(vec); +fail_pfnvec_create: kfree(buf); return NULL; @@ -145,20 +124,21 @@ static void vb2_vmalloc_put_userptr(void *buf_priv) struct vb2_vmalloc_buf *buf = buf_priv; unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK; unsigned int i; + struct page **pages; + unsigned int n_pages; - if (buf->pages) { + if (!buf->vec->is_pfns) { + n_pages = frame_vector_count(buf->vec); + pages = frame_vector_pages(buf->vec); if (vaddr) - vm_unmap_ram((void *)vaddr, buf->n_pages); - for (i = 0; i < buf->n_pages; ++i) { - if (buf->dma_dir == DMA_FROM_DEVICE) - set_page_dirty_lock(buf->pages[i]); - put_page(buf->pages[i]); - } - kfree(buf->pages); + vm_unmap_ram((void *)vaddr, n_pages); + if (buf->dma_dir == DMA_FROM_DEVICE) + for (i = 0; i < n_pages; i++) + set_page_dirty_lock(pages[i]); } else { - vb2_put_vma(buf->vma); iounmap((__force void __iomem *)buf->vaddr); } + vb2_destroy_framevec(buf->vec); kfree(buf); } -- cgit