Currently physmem_size is defined as long long but declared locally
as unsigned long long before using it in separate .c files. Make them
match by defining physmem_size as unsigned long long and also move
the declaration to a common header to allow the compiler to check it.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/drivers/virtio_uml.c       | 2 --
 arch/um/include/shared/as-layout.h | 2 ++
 arch/um/kernel/physmem.c           | 2 --
 arch/um/kernel/um_arch.c           | 2 +-
 4 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index e7f5556e3c96..4d3e9b9f5b61 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -72,8 +72,6 @@ struct virtio_uml_vq_info {
 	bool suspended;
 };
 
-extern unsigned long long physmem_size;
-
 #define vu_err(vu_dev, ...)	dev_err(&(vu_dev)->pdev->dev, ##__VA_ARGS__)
 
 /* Vhost-user protocol */
diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h
index 61965a06c18a..283226c34ca4 100644
--- a/arch/um/include/shared/as-layout.h
+++ b/arch/um/include/shared/as-layout.h
@@ -36,6 +36,8 @@ struct cpu_task {
 
 extern struct cpu_task cpu_tasks[];
 
+extern unsigned long long physmem_size;
+
 extern unsigned long high_physmem;
 extern unsigned long uml_physmem;
 extern unsigned long uml_reserved;
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index cc5238c1bf1e..cee3d09ba429 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -22,8 +22,6 @@ static int physmem_fd = -1;
 unsigned long high_physmem;
 EXPORT_SYMBOL(high_physmem);
 
-extern unsigned long long physmem_size;
-
 void __init mem_total_pages(unsigned long physmem, unsigned long iomem)
 {
 	unsigned long phys_pages, iomem_pages, total_pages;
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 8f86aa468b50..99cdf4b2d648 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -131,7 +131,7 @@ static int have_root __initdata;
 static int have_console __initdata;
 
 /* Set in uml_mem_setup and modified in linux_main */
-long long physmem_size = 64 * 1024 * 1024;
+unsigned long long physmem_size = 64 * 1024 * 1024;
 EXPORT_SYMBOL(physmem_size);
 
 static const char *usage_string =
-- 
2.34.1