From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>, Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Christoph Hellwig <hch@infradead.org>,
Jason Gunthorpe <jgg@nvidia.com>
Cc: Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH v2 05/12] iommu/vt-d: Unnecessary spinlock for root table alloc and free
Date: Tue, 14 Jun 2022 10:51:30 +0800 [thread overview]
Message-ID: <20220614025137.1632762-6-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20220614025137.1632762-1-baolu.lu@linux.intel.com>
The IOMMU root table is allocated and freed in the IOMMU initialization
code in static boot or hot-remove paths. There's no need for a spinlock.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
drivers/iommu/intel/iommu.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 839bb5f3e000..b2ef8af0c3f3 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -809,14 +809,12 @@ static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
static void free_context_table(struct intel_iommu *iommu)
{
- int i;
- unsigned long flags;
struct context_entry *context;
+ int i;
+
+ if (!iommu->root_entry)
+ return;
- spin_lock_irqsave(&iommu->lock, flags);
- if (!iommu->root_entry) {
- goto out;
- }
for (i = 0; i < ROOT_ENTRY_NR; i++) {
context = iommu_context_addr(iommu, i, 0, 0);
if (context)
@@ -828,12 +826,10 @@ static void free_context_table(struct intel_iommu *iommu)
context = iommu_context_addr(iommu, i, 0x80, 0);
if (context)
free_pgtable_page(context);
-
}
+
free_pgtable_page(iommu->root_entry);
iommu->root_entry = NULL;
-out:
- spin_unlock_irqrestore(&iommu->lock, flags);
}
#ifdef CONFIG_DMAR_DEBUG
@@ -1232,7 +1228,6 @@ static void domain_unmap(struct dmar_domain *domain, unsigned long start_pfn,
static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
struct root_entry *root;
- unsigned long flags;
root = (struct root_entry *)alloc_pgtable_page(iommu->node);
if (!root) {
@@ -1242,10 +1237,7 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
}
__iommu_flush_cache(iommu, root, ROOT_SIZE);
-
- spin_lock_irqsave(&iommu->lock, flags);
iommu->root_entry = root;
- spin_unlock_irqrestore(&iommu->lock, flags);
return 0;
}
--
2.25.1
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2022-06-14 2:55 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 2:51 [PATCH v2 00/12] iommu/vt-d: Optimize the use of locks Lu Baolu
2022-06-14 2:51 ` [PATCH v2 01/12] iommu/vt-d: debugfs: Remove device_domain_lock usage Lu Baolu
2022-06-14 6:43 ` Tian, Kevin
2022-06-14 7:15 ` Baolu Lu
2022-06-15 1:53 ` Baolu Lu
2022-06-15 6:13 ` Tian, Kevin
2022-06-15 13:02 ` Baolu Lu
2022-06-14 2:51 ` [PATCH v2 02/12] iommu/vt-d: Remove for_each_device_domain() Lu Baolu
2022-06-14 2:51 ` [PATCH v2 03/12] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() Lu Baolu
2022-06-14 6:49 ` Tian, Kevin
2022-06-14 7:21 ` Baolu Lu
2022-06-15 6:22 ` Tian, Kevin
2022-06-15 13:10 ` Baolu Lu
2022-06-16 4:00 ` Tian, Kevin
2022-06-14 2:51 ` [PATCH v2 04/12] iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk() Lu Baolu
2022-06-14 2:51 ` Lu Baolu [this message]
2022-06-14 2:51 ` [PATCH v2 06/12] iommu/vt-d: Acquiring lock in domain ID allocation helpers Lu Baolu
2022-06-14 6:52 ` Tian, Kevin
2022-06-14 7:22 ` Baolu Lu
2022-06-14 2:51 ` [PATCH v2 07/12] iommu/vt-d: Acquiring lock in pasid manipulation helpers Lu Baolu
2022-06-14 2:51 ` [PATCH v2 08/12] iommu/vt-d: Replace spin_lock_irqsave() with spin_lock() Lu Baolu
2022-06-14 6:56 ` Tian, Kevin
2022-06-14 2:51 ` [PATCH v2 09/12] iommu/vt-d: Check device list of domain in domain free path Lu Baolu
2022-06-14 6:57 ` Tian, Kevin
2022-06-14 2:51 ` [PATCH v2 10/12] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller Lu Baolu
2022-06-14 7:07 ` Tian, Kevin
2022-06-14 7:44 ` Baolu Lu
2022-06-14 2:51 ` [PATCH v2 11/12] iommu/vt-d: Use device_domain_lock accurately Lu Baolu
2022-06-14 7:16 ` Tian, Kevin
2022-06-14 7:47 ` Baolu Lu
2022-06-14 2:51 ` [PATCH v2 12/12] iommu/vt-d: Convert global spinlock into per domain ones Lu Baolu
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