From 7ba34a94f46d65bde38036285dee0bf6e3a3ab7a Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 30 Mar 2020 17:34:54 +0800 Subject: [PATCH 0903/2944] iommu/amd: Remove amd_iommu_devtable_lock fix #26319040 commit 3a11905b69eb026402448c750f97a0eadfa76b08 upstream. The lock is not necessary because the device table does not contain shared state that needs protection. Locking is only needed on an individual entry basis, and that needs to happen on the iommu_dev_data level. Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path") Reviewed-by: Filippo Sironi Reviewed-by: Jerry Snitselaar Signed-off-by: Joerg Roedel Signed-off-by: tianyi Reviewed-by: zhangliguang Acked-by: zhangliguang --- drivers/iommu/amd_iommu.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 63c336c5..0cb03cd 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -79,7 +79,6 @@ */ #define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38)) -static DEFINE_SPINLOCK(amd_iommu_devtable_lock); static DEFINE_SPINLOCK(pd_bitmap_lock); /* List of all available dev_data structures */ @@ -2005,10 +2004,11 @@ static void do_detach(struct iommu_dev_data *dev_data) static int __attach_device(struct iommu_dev_data *dev_data, struct protection_domain *domain) { + unsigned long flags; int ret; /* lock domain */ - spin_lock(&domain->lock); + spin_lock_irqsave(&domain->lock, flags); ret = -EBUSY; if (dev_data->domain != NULL) @@ -2022,7 +2022,7 @@ static int __attach_device(struct iommu_dev_data *dev_data, out_unlock: /* ready */ - spin_unlock(&domain->lock); + spin_unlock_irqrestore(&domain->lock, flags); return ret; } @@ -2123,7 +2123,6 @@ static int attach_device(struct device *dev, { struct pci_dev *pdev; struct iommu_dev_data *dev_data; - unsigned long flags; int ret; dev_data = get_dev_data(dev); @@ -2151,9 +2150,7 @@ static int attach_device(struct device *dev, } skip_ats_check: - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); ret = __attach_device(dev_data, domain); - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); /* * We might boot into a crash-kernel here. The crashed kernel @@ -2173,14 +2170,15 @@ static int attach_device(struct device *dev, static void __detach_device(struct iommu_dev_data *dev_data) { struct protection_domain *domain; + unsigned long flags; domain = dev_data->domain; - spin_lock(&domain->lock); + spin_lock_irqsave(&domain->lock, flags); do_detach(dev_data); - spin_unlock(&domain->lock); + spin_unlock_irqrestore(&domain->lock, flags); } /* @@ -2190,7 +2188,6 @@ static void detach_device(struct device *dev) { struct protection_domain *domain; struct iommu_dev_data *dev_data; - unsigned long flags; dev_data = get_dev_data(dev); domain = dev_data->domain; @@ -2204,10 +2201,7 @@ static void detach_device(struct device *dev) if (WARN_ON(!dev_data->domain)) return; - /* lock device table */ - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); __detach_device(dev_data); - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); if (!dev_is_pci(dev)) return; @@ -2864,9 +2858,6 @@ int __init amd_iommu_init_dma_ops(void) static void cleanup_domain(struct protection_domain *domain) { struct iommu_dev_data *entry; - unsigned long flags; - - spin_lock_irqsave(&amd_iommu_devtable_lock, flags); while (!list_empty(&domain->dev_list)) { entry = list_first_entry(&domain->dev_list, @@ -2874,8 +2865,6 @@ static void cleanup_domain(struct protection_domain *domain) BUG_ON(!entry->domain); __detach_device(entry); } - - spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags); } static void protection_domain_free(struct protection_domain *domain) -- 1.8.3.1