Re: [PATCH v5 09/11] powerpc/pseries/iommu: Find existing DDW with given property name

[Frederic Barrat]

On 16/07/2021 10:27, Leonardo Bras wrote:

At the moment pseries stores information about created directly mapped
DDW window in DIRECT64_PROPNAME.

With the objective of implementing indirect DMA mapping with DDW, it's
necessary to have another propriety name to make sure kexec'ing into older
kernels does not break, as it would if we reuse DIRECT64_PROPNAME.

In order to have this, find_existing_ddw_windows() needs to be able to
look for different property names.

Extract find_existing_ddw_windows() into find_existing_ddw_windows_named()
and calls it with current property name.

Signed-off-by: Leonardo Bras <leobra...@gmail.com>
Reviewed-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---

Reviewed-by: Frederic Barrat <fbar...@linux.ibm.com>

  arch/powerpc/platforms/pseries/iommu.c | 25 +++++++++++++++----------
  1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c 
b/arch/powerpc/platforms/pseries/iommu.c
index 17c6f4706e76..22d251e15b61 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -895,24 +895,21 @@ static struct direct_window *ddw_list_new_entry(struct 
device_node *pdn,
        return window;
  }

-static int find_existing_ddw_windows(void)

+static void find_existing_ddw_windows_named(const char *name)
  {
        int len;
        struct device_node *pdn;
        struct direct_window *window;
-       const struct dynamic_dma_window_prop *direct64;
-
-       if (!firmware_has_feature(FW_FEATURE_LPAR))
-               return 0;
+       const struct dynamic_dma_window_prop *dma64;

- for_each_node_with_property(pdn, DIRECT64_PROPNAME) {

-               direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
-               if (!direct64 || len < sizeof(*direct64)) {
-                       remove_ddw(pdn, true, DIRECT64_PROPNAME);
+       for_each_node_with_property(pdn, name) {
+               dma64 = of_get_property(pdn, name, &len);
+               if (!dma64 || len < sizeof(*dma64)) {
+                       remove_ddw(pdn, true, name);
                        continue;
                }

- window = ddw_list_new_entry(pdn, direct64);

+               window = ddw_list_new_entry(pdn, dma64);
                if (!window)
                        break;

@@ -920,6 +917,14 @@ static int find_existing_ddw_windows(void)

                list_add(&window->list, &direct_window_list);
                spin_unlock(&direct_window_list_lock);
        }
+}
+
+static int find_existing_ddw_windows(void)
+{
+       if (!firmware_has_feature(FW_FEATURE_LPAR))
+               return 0;
+
+       find_existing_ddw_windows_named(DIRECT64_PROPNAME);

return 0;

  }