Commit 74f6d776 authored by Parav Pandit's avatar Parav Pandit Committed by Joerg Roedel
Browse files

iommu/vt-d: Removed unused iommu_count in dmar domain 



DMAR domain uses per DMAR refcount. It is indexed by iommu seq_id.
Older iommu_count is only incremented and decremented but no decisions
are taken based on this refcount. This is not of much use.

Hence, remove iommu_count and further simplify domain_detach_iommu()
by returning void.

Signed-off-by: default avatarParav Pandit <parav@nvidia.com>
Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210530075053.264218-1-parav@nvidia.com
Link: https://lore.kernel.org/r/20210610020115.1637656-21-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 1f106ff0

drivers/iommu/intel/iommu.c

+3 −8
Original line number Diff line number Diff line
@@ -1920,7 +1920,6 @@ static int domain_attach_iommu(struct dmar_domain *domain, 
	assert_spin_locked(&iommu->lock);



	domain->iommu_refcnt[iommu->seq_id] += 1;

	domain->iommu_count += 1;

	if (domain->iommu_refcnt[iommu->seq_id] == 1) {

		ndomains = cap_ndoms(iommu->cap);

		num      = find_first_zero_bit(iommu->domain_ids, ndomains);
@@ -1928,7 +1927,6 @@ static int domain_attach_iommu(struct dmar_domain *domain, 
		if (num >= ndomains) {

			pr_err("%s: No free domain ids\n", iommu->name);

			domain->iommu_refcnt[iommu->seq_id] -= 1;

			domain->iommu_count -= 1;

			return -ENOSPC;

		}
@@ -1944,16 +1942,15 @@ static int domain_attach_iommu(struct dmar_domain *domain, 
	return 0;

}



static int domain_detach_iommu(struct dmar_domain *domain,

static void domain_detach_iommu(struct dmar_domain *domain,

				struct intel_iommu *iommu)

{

	int num, count;

	int num;



	assert_spin_locked(&device_domain_lock);

	assert_spin_locked(&iommu->lock);



	domain->iommu_refcnt[iommu->seq_id] -= 1;

	count = --domain->iommu_count;

	if (domain->iommu_refcnt[iommu->seq_id] == 0) {

		num = domain->iommu_did[iommu->seq_id];

		clear_bit(num, iommu->domain_ids);
@@ -1962,8 +1959,6 @@ static int domain_detach_iommu(struct dmar_domain *domain, 
		domain_update_iommu_cap(domain);

		domain->iommu_did[iommu->seq_id] = 0;

	}



	return count;

}



static inline int guestwidth_to_adjustwidth(int gaw)

include/linux/intel-iommu.h

+0 −1
Original line number Diff line number Diff line
@@ -561,7 +561,6 @@ struct dmar_domain { 
	int		agaw;



	int		flags;		/* flags to find out type of domain */

	int		iommu_count;	/* reference count of iommu */

	int		iommu_superpage;/* Level of superpages supported:

					   0 == 4KiB (no superpages), 1 == 2MiB,

					   2 == 1GiB, 3 == 512GiB, 4 == 1TiB */