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From: Parav Pandit <parav@nvidia.com>
To: <dwmw2@infradead.org>, <baolu.lu@linux.intel.com>,
	<iommu@lists.linux-foundation.org>
Cc: will@kernel.org
Subject: [PATCH 2/5] iommu/intel: Removed unused iommu_count in dmar domain
Date: Sun, 30 May 2021 10:50:50 +0300	[thread overview]
Message-ID: <20210530075053.264218-3-parav@nvidia.com> (raw)
In-Reply-To: <20210530075053.264218-1-parav@nvidia.com>

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>
---
 drivers/iommu/intel/iommu.c | 11 +++--------
 include/linux/intel-iommu.h |  1 -
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cdbf4513df9d..51be77c48108 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1919,7 +1919,6 @@ 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);
@@ -1927,7 +1926,6 @@ 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;
 		}
 
@@ -1943,16 +1941,15 @@ 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);
@@ -1961,8 +1958,6 @@ 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)
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 2153c6cbef7e..50a006cc8c05 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -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 */
-- 
2.26.2

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  parent reply	other threads:[~2021-05-30  7:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-30  7:50 [PATCH 0/5] Short cleanups around DMAR Parav Pandit
2021-05-30  7:50 ` [PATCH 1/5] iommu/intel: Use bitfields for DMAR capabilities Parav Pandit
2021-05-30  7:50 ` Parav Pandit [this message]
2021-05-30  7:50 ` [PATCH 3/5] iommu/intel: Remove unnecessary braces Parav Pandit
2021-05-30  7:50 ` [PATCH 4/5] iommu/intel: Define counter explicitly as unsigned int Parav Pandit
2021-05-30  7:50 ` [PATCH 5/5] iommu/intel: No need to typecast Parav Pandit
2021-06-09  7:43 ` [PATCH 0/5] Short cleanups around DMAR Lu Baolu

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