2 files changed, 37 insertions, 16 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 96de97a46079..4025291ea0ae 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -940,15 +940,13 @@ static void build_inv_irt(struct iommu_cmd *cmd, u16 devid)
  * Writes the command to the IOMMUs command buffer and informs the
  * hardware about the new command.
  */
-static int iommu_queue_command_sync(struct amd_iommu *iommu,
-                                    struct iommu_cmd *cmd,
-                                    bool sync)
+static int __iommu_queue_command_sync(struct amd_iommu *iommu,
+                                      struct iommu_cmd *cmd,
+                                      bool sync)
 {
         u32 left, tail, head, next_tail;
-        unsigned long flags;
 
 again:
-        spin_lock_irqsave(&iommu->lock, flags);
 
         head      = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
         tail      = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
@@ -957,15 +955,14 @@ again:
 
         if (left <= 2) {
                 struct iommu_cmd sync_cmd;
-                volatile u64 sem = 0;
                 int ret;
 
-                build_completion_wait(&sync_cmd, (u64)&sem);
-                copy_cmd_to_buffer(iommu, &sync_cmd, tail);
+                iommu->cmd_sem = 0;
 
-                spin_unlock_irqrestore(&iommu->lock, flags);
+                build_completion_wait(&sync_cmd, (u64)&iommu->cmd_sem);
+                copy_cmd_to_buffer(iommu, &sync_cmd, tail);
 
-                if ((ret = wait_on_sem(&sem)) != 0)
+                if ((ret = wait_on_sem(&iommu->cmd_sem)) != 0)
                         return ret;
 
                 goto again;
@@ -976,9 +973,21 @@ again:
         /* We need to sync now to make sure all commands are processed */
         iommu->need_sync = sync;
 
+        return 0;
+}
+
+static int iommu_queue_command_sync(struct amd_iommu *iommu,
+                                    struct iommu_cmd *cmd,
+                                    bool sync)
+{
+        unsigned long flags;
+        int ret;
+
+        spin_lock_irqsave(&iommu->lock, flags);
+        ret = __iommu_queue_command_sync(iommu, cmd, sync);
         spin_unlock_irqrestore(&iommu->lock, flags);
 
-        return 0;
+        return ret;
 }
 
 static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
@@ -993,19 +1002,29 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
 static int iommu_completion_wait(struct amd_iommu *iommu)
 {
         struct iommu_cmd cmd;
-        volatile u64 sem = 0;
+        unsigned long flags;
         int ret;
 
         if (!iommu->need_sync)
                 return 0;
 
-        build_completion_wait(&cmd, (u64)&sem);
 
-        ret = iommu_queue_command_sync(iommu, &cmd, false);
+        build_completion_wait(&cmd, (u64)&iommu->cmd_sem);
+
+        spin_lock_irqsave(&iommu->lock, flags);
+
+        iommu->cmd_sem = 0;
+
+        ret = __iommu_queue_command_sync(iommu, &cmd, false);
         if (ret)
-                return ret;
+                goto out_unlock;
+
+        ret = wait_on_sem(&iommu->cmd_sem);
 
-        return wait_on_sem(&sem);
+out_unlock:
+        spin_unlock_irqrestore(&iommu->lock, flags);
+
+        return ret;
 }
 
 static int iommu_flush_dte(struct amd_iommu *iommu, u16 devid)
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index caf5e3822715..9652848e3155 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -524,6 +524,8 @@ struct amd_iommu {
         struct irq_domain *ir_domain;
         struct irq_domain *msi_domain;
 #endif
+
+        volatile u64 __aligned(8) cmd_sem;
 };
 
 #define ACPIHID_UID_LEN 256