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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: Parav Pandit <parav@nvidia.com>
Signed-off-by: Lu 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: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Parav Pandit 2021-06-10 10:01:12 +08:00 committed by Joerg Roedel
parent 1f106ff0ea
commit 74f6d776ae
2 changed files with 3 additions and 9 deletions
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11
drivers/iommu/intel/iommu.c
View File

@ -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,
struct intel_iommu *iommu)
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)

1
include/linux/intel-iommu.h
View File

@ -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 */