Re: [PATCH v6 07/33] iommu: Avoid reallocate default domain for a group
From: Robin Murphy <robin.murphy@arm.com>
Date: 2021-01-29 00:05:08
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linux-devicetree, linux-iommu, linux-mediatek, lkml
On 2021-01-28 21:14, 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.
FWIW patch #6 gets dropped as well now, since Rob has applied the standalone fix (89c7cb1608ac). Robin.
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 Will
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