From: Sebastian Andrzej Siewior Date: Thu, 22 Mar 2018 16:22:35 +0100 Subject: [PATCH 03/10] iommu/amd: Split domain id out of amd_iommu_devtable_lock Upstream commit 2bc00180890427dcc092b2f2b0d03c904bcade29 domain_id_alloc() and domain_id_free() is used for id management. Those two function share a bitmap (amd_iommu_pd_alloc_bitmap) and set/clear bits based on id allocation. There is no need to share this with amd_iommu_devtable_lock, it can use its own lock for this operation. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -81,6 +81,7 @@ #define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38)) static DEFINE_RWLOCK(amd_iommu_devtable_lock); +static DEFINE_SPINLOCK(pd_bitmap_lock); /* List of all available dev_data structures */ static LLIST_HEAD(dev_data_list); @@ -1599,29 +1600,26 @@ static void del_domain_from_list(struct static u16 domain_id_alloc(void) { - unsigned long flags; int id; - write_lock_irqsave(&amd_iommu_devtable_lock, flags); + spin_lock(&pd_bitmap_lock); id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID); BUG_ON(id == 0); if (id > 0 && id < MAX_DOMAIN_ID) __set_bit(id, amd_iommu_pd_alloc_bitmap); else id = 0; - write_unlock_irqrestore(&amd_iommu_devtable_lock, flags); + spin_unlock(&pd_bitmap_lock); return id; } static void domain_id_free(int id) { - unsigned long flags; - - write_lock_irqsave(&amd_iommu_devtable_lock, flags); + spin_lock(&pd_bitmap_lock); if (id > 0 && id < MAX_DOMAIN_ID) __clear_bit(id, amd_iommu_pd_alloc_bitmap); - write_unlock_irqrestore(&amd_iommu_devtable_lock, flags); + spin_unlock(&pd_bitmap_lock); } #define DEFINE_FREE_PT_FN(LVL, FN) \