[xen master] xen/iommu: protect iommu_add_dt_device() with dtdevs_lock

[patchbot@xxxxxxx]

commit 6b0e3b74cb4cc245c3b7fa2019fc40c5212e1ce4
Author:     Vikram Garhwal <vikram.garhwal@xxxxxxx>
AuthorDate: Tue Sep 5 18:16:20 2023 -0700
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Tue Sep 5 18:26:07 2023 -0700

    xen/iommu: protect iommu_add_dt_device() with dtdevs_lock
    
    Protect iommu_add_dt_device() with dtdevs_lock to prevent concurrent access
    to add/remove/assign/deassign.
    With addition of dynamic programming feature(follow-up patches in this 
series),
    this function can be concurrently accessed by dynamic node add/remove using
    device tree overlays.
    
    Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
    Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/drivers/passthrough/device_tree.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/xen/drivers/passthrough/device_tree.c 
b/xen/drivers/passthrough/device_tree.c
index a7d86a20a0..687c61e7da 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -147,6 +147,8 @@ int iommu_add_dt_device(struct dt_device_node *np)
     if ( dev_iommu_fwspec_get(dev) )
         return 0;
 
+    spin_lock(&dtdevs_lock);
+
     /*
      * According to the Documentation/devicetree/bindings/iommu/iommu.txt
      * from Linux.
@@ -159,7 +161,10 @@ int iommu_add_dt_device(struct dt_device_node *np)
          * these callback implemented.
          */
         if ( !ops->add_device || !ops->dt_xlate )
-            return -EINVAL;
+        {
+            rc = -EINVAL;
+            goto fail;
+        }
 
         if ( !dt_device_is_available(iommu_spec.np) )
             break;
@@ -190,6 +195,8 @@ int iommu_add_dt_device(struct dt_device_node *np)
     if ( rc < 0 )
         iommu_fwspec_free(dev);
 
+ fail:
+    spin_unlock(&dtdevs_lock);
     return rc;
 }
 
--
generated by git-patchbot for /home/xen/git/xen.git#master