Dynamic programming ops will modify the dt_host and there might be other
function which are browsing the dt_host at the same time. To avoid the race
conditions, adding rwlock for browsing the dt_host. But adding rwlock in
device_tree.h causes following circular dependency:
    device_tree.h->rwlock.h->smp.h->asm/smp.h->device_tree.h

To fix this, removed the "#include <xen/device_tree.h> and forward declared
"struct dt_device_node".

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
---
 xen/arch/arm/include/asm/smp.h | 3 ++-
 xen/arch/arm/smpboot.c         | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/include/asm/smp.h b/xen/arch/arm/include/asm/smp.h
index 8133d5c295..afe6129276 100644
--- a/xen/arch/arm/include/asm/smp.h
+++ b/xen/arch/arm/include/asm/smp.h
@@ -3,13 +3,14 @@
 
 #ifndef __ASSEMBLY__
 #include <xen/cpumask.h>
-#include <xen/device_tree.h>
 #include <asm/current.h>
 #endif
 
 DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
 DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
 
+struct dt_device_node;
+
 #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
 
 #define smp_processor_id() get_processor_id()
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 412ae22869..336a7d418b 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -11,6 +11,7 @@
 #include <xen/cpumask.h>
 #include <xen/delay.h>
 #include <xen/domain_page.h>
+#include <xen/device_tree.h>
 #include <xen/errno.h>
 #include <xen/init.h>
 #include <xen/mm.h>
-- 
2.17.1

Hi Vikram,

On 11/04/2023 21:16, Vikram Garhwal wrote:
> 
> 
> Dynamic programming ops will modify the dt_host and there might be other
> function which are browsing the dt_host at the same time. To avoid the race
> conditions, adding rwlock for browsing the dt_host. But adding rwlock in
> device_tree.h causes following circular dependency:
>     device_tree.h->rwlock.h->smp.h->asm/smp.h->device_tree.h
> 
> To fix this, removed the "#include <xen/device_tree.h> and forward declared
> "struct dt_device_node".
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
> ---
>  xen/arch/arm/include/asm/smp.h | 3 ++-
>  xen/arch/arm/smpboot.c         | 1 +
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/include/asm/smp.h b/xen/arch/arm/include/asm/smp.h
> index 8133d5c295..afe6129276 100644
> --- a/xen/arch/arm/include/asm/smp.h
> +++ b/xen/arch/arm/include/asm/smp.h
> @@ -3,13 +3,14 @@
> 
>  #ifndef __ASSEMBLY__
>  #include <xen/cpumask.h>
> -#include <xen/device_tree.h>
>  #include <asm/current.h>
>  #endif
> 
>  DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
>  DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
> 
> +struct dt_device_node;
> +
>  #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
> 
>  #define smp_processor_id() get_processor_id()
> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> index 412ae22869..336a7d418b 100644
> --- a/xen/arch/arm/smpboot.c
> +++ b/xen/arch/arm/smpboot.c
> @@ -11,6 +11,7 @@
>  #include <xen/cpumask.h>
>  #include <xen/delay.h>
>  #include <xen/domain_page.h>
> +#include <xen/device_tree.h>
Headers should be listed in alphabetical order, so device_tree.h goes before domain_page.h

Other than that:
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

~Michal

Hi Vikram,

> -----Original Message-----
> Subject: [XEN][PATCH v5 11/17] asm/smp.h: Fix circular dependency for
> device_tree.h and rwlock.h
> 
> Dynamic programming ops will modify the dt_host and there might be other
> function which are browsing the dt_host at the same time. To avoid the race
> conditions, adding rwlock for browsing the dt_host. But adding rwlock in
> device_tree.h causes following circular dependency:
>     device_tree.h->rwlock.h->smp.h->asm/smp.h->device_tree.h
> 
> To fix this, removed the "#include <xen/device_tree.h> and forward declared
> "struct dt_device_node".
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>

Reviewed-by: Henry Wang <Henry.Wang@arm.com>

Kind regards,
Henry