From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Tue, 3 Nov 2015 13:17:34 +0000 Subject: [RFC] iommu: arm-smmu: correct reference count In-Reply-To: <1446555557-3097-1-git-send-email-van.freenix@gmail.com> References: <1446555557-3097-1-git-send-email-van.freenix@gmail.com> Message-ID: <20151103131734.GE14159@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote: > iommu_group_alloc will initialize the reference count for group to 1. > iommu_group_add_device also increase the group reference count, > if nothing bad happends. And we need to add iommu_group_put to > decrease the reference count for group. > > Signed-off-by: Peng Fan > Cc: Will Deacon > Cc: Joerg Roedel > --- > > Not sure whether my understanding is correct or not. I checked rockchip-iommu.c > exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after > iommu_group_add_device. Doesn't this pair up with the iommu_group_remove_device in arm_smmu_remove_device? Are you actually seeing an issue in practice? Will