diff mbox series

[XEN,v5,08/17] xen/iommu: Move spin_lock from iommu_dt_device_is_assigned to caller

Message ID 20230411191636.26926-9-vikram.garhwal@amd.com (mailing list archive)
State Superseded
Headers show
Series dynamic node programming using overlay dtbo | expand

Commit Message

Vikram Garhwal April 11, 2023, 7:16 p.m. UTC
Rename iommu_dt_device_is_assigned() to iommu_dt_device_is_assigned_lock().

Moving spin_lock to caller was done to prevent the concurrent access to
iommu_dt_device_is_assigned while doing add/remove/assign/deassign.

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
---
 xen/drivers/passthrough/device_tree.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

Comments

Michal Orzel April 17, 2023, 9:14 a.m. UTC | #1
Hi Vikram,

It looks like you didn't take into account any of my remarks made for v4.
I will repeat them here.

On 11/04/2023 21:16, Vikram Garhwal wrote:
> 
> 
> Rename iommu_dt_device_is_assigned() to iommu_dt_device_is_assigned_lock().
s/lock/locked

> 
> Moving spin_lock to caller was done to prevent the concurrent access to
> iommu_dt_device_is_assigned while doing add/remove/assign/deassign.
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
> Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
> ---
>  xen/drivers/passthrough/device_tree.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
> index 1c32d7b50c..bb4cf7784d 100644
> --- a/xen/drivers/passthrough/device_tree.c
> +++ b/xen/drivers/passthrough/device_tree.c
> @@ -83,16 +83,15 @@ fail:
>      return rc;
>  }
> 
> -static bool_t iommu_dt_device_is_assigned(const struct dt_device_node *dev)
> +static bool_t
> +    iommu_dt_device_is_assigned_locked(const struct dt_device_node *dev)
This should not be indented.

>  {
>      bool_t assigned = 0;
> 
>      if ( !dt_device_is_protected(dev) )
>          return 0;
> 
> -    spin_lock(&dtdevs_lock);
>      assigned = !list_empty(&dev->domain_list);
> -    spin_unlock(&dtdevs_lock);
> 
>      return assigned;
>  }
> @@ -213,27 +212,43 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
>          if ( (d && d->is_dying) || domctl->u.assign_device.flags )
>              break;
> 
> +        spin_lock(&dtdevs_lock);
> +
>          ret = dt_find_node_by_gpath(domctl->u.assign_device.u.dt.path,
>                                      domctl->u.assign_device.u.dt.size,
>                                      &dev);
>          if ( ret )
> +        {
> +            spin_unlock(&dtdevs_lock);
> +
Please, do not add blank line between spin_unlock and break. It does not improve readability.

>              break;
> +        }
> 
>          ret = xsm_assign_dtdevice(XSM_HOOK, d, dt_node_full_name(dev));
>          if ( ret )
> +        {
> +            spin_unlock(&dtdevs_lock);
> +
same here.

~Michal
diff mbox series

Patch

diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index 1c32d7b50c..bb4cf7784d 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -83,16 +83,15 @@  fail:
     return rc;
 }
 
-static bool_t iommu_dt_device_is_assigned(const struct dt_device_node *dev)
+static bool_t
+    iommu_dt_device_is_assigned_locked(const struct dt_device_node *dev)
 {
     bool_t assigned = 0;
 
     if ( !dt_device_is_protected(dev) )
         return 0;
 
-    spin_lock(&dtdevs_lock);
     assigned = !list_empty(&dev->domain_list);
-    spin_unlock(&dtdevs_lock);
 
     return assigned;
 }
@@ -213,27 +212,43 @@  int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
         if ( (d && d->is_dying) || domctl->u.assign_device.flags )
             break;
 
+        spin_lock(&dtdevs_lock);
+
         ret = dt_find_node_by_gpath(domctl->u.assign_device.u.dt.path,
                                     domctl->u.assign_device.u.dt.size,
                                     &dev);
         if ( ret )
+        {
+            spin_unlock(&dtdevs_lock);
+
             break;
+        }
 
         ret = xsm_assign_dtdevice(XSM_HOOK, d, dt_node_full_name(dev));
         if ( ret )
+        {
+            spin_unlock(&dtdevs_lock);
+
             break;
+        }
 
         if ( domctl->cmd == XEN_DOMCTL_test_assign_device )
         {
-            if ( iommu_dt_device_is_assigned(dev) )
+
+            if ( iommu_dt_device_is_assigned_locked(dev) )
             {
                 printk(XENLOG_G_ERR "%s already assigned.\n",
                        dt_node_full_name(dev));
                 ret = -EINVAL;
             }
+
+            spin_unlock(&dtdevs_lock);
+
             break;
         }
 
+        spin_unlock(&dtdevs_lock);
+
         if ( d == dom_io )
             return -EINVAL;