From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: [PATCH 12/25] iommu/vt-d: Unnecessary spinlock for root table alloc and free
Date: Tue, 12 Jul 2022 08:08:55 +0800 [thread overview]
Message-ID: <20220712000908.3431936-13-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20220712000908.3431936-1-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>
Link: https://lore.kernel.org/r/20220706025524.2904370-5-baolu.lu@linux.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 77915d61f7ec..ff49c9460ede 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
next prev parent reply other threads:[~2022-07-12 0:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-12 0:08 [PATCH 00/25] [PULL REQUEST] Intel IOMMU updates for Linux v5.20 Lu Baolu
2022-07-12 0:08 ` [PATCH 01/25] iommu/vt-d: Move trace/events/intel_iommu.h under iommu Lu Baolu
2022-07-12 0:08 ` [PATCH 02/25] agp/intel: Use per device iommu check Lu Baolu
2022-07-12 0:08 ` [PATCH 03/25] iommu/vt-d: Remove unnecessary exported symbol Lu Baolu
2022-07-12 0:08 ` [PATCH 04/25] drm/i915: Remove unnecessary include Lu Baolu
2022-07-12 0:08 ` [PATCH 05/25] KVM: x86: " Lu Baolu
2022-07-12 0:08 ` [PATCH 06/25] x86/boot/tboot: Move tboot_force_iommu() to Intel IOMMU Lu Baolu
2022-07-12 0:08 ` [PATCH 07/25] iommu/vt-d: Move include/linux/intel-iommu.h under iommu Lu Baolu
2022-07-12 0:08 ` [PATCH 08/25] iommu/vt-d: Remove unused iovad from dmar_domain Lu Baolu
2022-07-12 0:08 ` [PATCH 09/25] iommu/vt-d: debugfs: Remove device_domain_lock usage Lu Baolu
2022-07-12 0:08 ` [PATCH 10/25] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() Lu Baolu
2022-07-12 0:08 ` [PATCH 11/25] iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk() Lu Baolu
2022-07-12 0:08 ` Lu Baolu [this message]
2022-07-12 0:08 ` [PATCH 13/25] iommu/vt-d: Replace spin_lock_irqsave() with spin_lock() Lu Baolu
2022-07-12 0:08 ` [PATCH 14/25] iommu/vt-d: Acquiring lock in domain ID allocation helpers Lu Baolu
2022-07-12 0:08 ` [PATCH 15/25] iommu/vt-d: Acquiring lock in pasid manipulation helpers Lu Baolu
2022-07-12 0:08 ` [PATCH 16/25] iommu/vt-d: Check device list of domain in domain free path Lu Baolu
2022-07-12 0:09 ` [PATCH 17/25] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller Lu Baolu
2022-07-12 0:09 ` [PATCH 18/25] iommu/vt-d: Use device_domain_lock accurately Lu Baolu
2022-07-12 0:09 ` [PATCH 19/25] iommu/vt-d: Convert global spinlock into per domain lock Lu Baolu
2022-07-12 0:09 ` [PATCH 20/25] iommu/vt-d: Remove unused domain_get_iommu() Lu Baolu
2022-07-12 0:09 ` [PATCH 21/25] iommu/vt-d: Use IDA interface to manage iommu sequence id Lu Baolu
2022-07-12 0:09 ` [PATCH 22/25] iommu/vt-d: Refactor iommu information of each domain Lu Baolu
2022-07-12 0:09 ` [PATCH 23/25] iommu/vt-d: Remove unnecessary check in intel_iommu_add() Lu Baolu
2022-07-12 0:09 ` [PATCH 24/25] iommu/vt-d: Remove global g_iommus array Lu Baolu
2022-07-12 0:09 ` [PATCH 25/25] iommu/vt-d: Make DMAR_UNITS_SUPPORTED default 1024 Lu Baolu
2022-07-15 8:22 ` [PATCH 00/25] [PULL REQUEST] Intel IOMMU updates for Linux v5.20 Joerg Roedel
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