lkml.org 
[lkml]   [2022]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 1/5] vduse: Remove unnecessary spin lock protection
From

在 2022/7/6 13:04, Xie Yongji 写道:
> Taking iotlb lock to access bounce page in page fault
> handler is meaningless since vduse_domain_free_bounce_pages()
> would only be called during file release.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
> drivers/vdpa/vdpa_user/iova_domain.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
> index 6daa3978d290..bca1f0b8850c 100644
> --- a/drivers/vdpa/vdpa_user/iova_domain.c
> +++ b/drivers/vdpa/vdpa_user/iova_domain.c
> @@ -211,17 +211,14 @@ static struct page *
> vduse_domain_get_bounce_page(struct vduse_iova_domain *domain, u64 iova)
> {
> struct vduse_bounce_map *map;
> - struct page *page = NULL;
> + struct page *page;
>
> - spin_lock(&domain->iotlb_lock);
> map = &domain->bounce_maps[iova >> PAGE_SHIFT];
> if (!map->bounce_page)
> - goto out;
> + return NULL;


Interesting, I wonder why we don't serialize with
vduse_domain_map_bounce_page() with iotlb_lock?

Thanks


>
> page = map->bounce_page;
> get_page(page);
> -out:
> - spin_unlock(&domain->iotlb_lock);
>
> return page;
> }

\
 
 \ /
  Last update: 2022-07-13 07:45    [W:0.172 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site