Re: [PATCH v6 07/33] iommu: Avoid reallocate default domain for a group
From: Yong Wu <yong.wu@mediatek.com>
Date: 2021-01-29 01:53:43
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linux-arm-kernel, linux-iommu, linux-mediatek, lkml
On Thu, 2021-01-28 at 21:14 +0000, Will Deacon wrote:
On Thu, Jan 28, 2021 at 09:10:20PM +0000, Will Deacon wrote:quoted
On Wed, Jan 27, 2021 at 05:39:16PM +0800, Yong Wu wrote:quoted
On Tue, 2021-01-26 at 22:23 +0000, Will Deacon wrote:quoted
On Mon, Jan 11, 2021 at 07:18:48PM +0800, Yong Wu wrote:quoted
If group->default_domain exists, avoid reallocate it. In some iommu drivers, there may be several devices share a group. Avoid realloc the default domain for this case. Signed-off-by: Yong Wu <yong.wu@mediatek.com> --- drivers/iommu/iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 3d099a31ddca..f4b87e6abe80 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c@@ -266,7 +266,8 @@ int iommu_probe_device(struct device *dev) * support default domains, so the return value is not yet * checked. */ - iommu_alloc_default_domain(group, dev); + if (!group->default_domain) + iommu_alloc_default_domain(group, dev);I don't really get what this achieves, since iommu_alloc_default_domain() looks like this: static int iommu_alloc_default_domain(struct iommu_group *group, struct device *dev) { unsigned int type; if (group->default_domain) return 0; ... in which case, it should be fine?oh. sorry, I overlooked this. the current code is enough. I will remove this patch. and send the next version in this week. Thanks very much.Actually, looking at this again, if we're dropping this patch and patch 6 just needs the kfree() moving about, then there's no need to repost. The issue that Robin and Paul are discussing can be handled separately.Argh, except that this version of the patches doesn't apply :) So after all that, please go ahead and post a v7 ASAP based on this branch: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=for-joerg/mtk
After confirm with Tomasz, He still need some time to take a look at v6. thus I need wait some time to send v7 after his feedback. Thanks for your comment. and Thanks Tomasz for the review.
Will