[PATCH 0/5] treewide: remove unreachable memblock_reserve() return value checks in early boot

[PATCH 0/5] treewide: remove unreachable memblock_reserve() return value checks in early boot

[Sang-Heon Jeon]

memblock_reserve() can only return an error after memblock_allow_resize()
has been called. Before that it either succeeds or panics, never returning
an error.

Before memblock_allow_resize() is called, the return value checks of
memblock_reserve() are unreachable and can be removed.

All the call sites are in different trees, so I split the change into one
patch per arch/subsystem. The patches are independent and can be applied
separately.

Sang-Heon Jeon (5):
  x86/setup: remove unreachable memblock_reserve() return value check
  sh: remove unreachable memblock_reserve() return value check
  powerpc/fadump: remove unreachable memblock_reserve() return value
    checks
  xtensa: remove unreachable memblock_reserve() return value checks
  Revert "tpm: do not ignore memblock_reserve return value"

 arch/powerpc/kernel/fadump.c   | 14 +++-----------
 arch/sh/kernel/machine_kexec.c |  7 +------
 arch/x86/kernel/setup.c        |  7 ++-----
 arch/xtensa/kernel/setup.c     | 13 +++++++------
 drivers/firmware/efi/tpm.c     |  7 +------
 5 files changed, 14 insertions(+), 34 deletions(-)

-- 
2.43.0

[PATCH 3/5] powerpc/fadump: remove unreachable memblock_reserve() return value checks

[Sang-Heon Jeon]

fadump_append_bootargs() and fadump_reserve_mem() both run from
early_init_devtree(), before it calls memblock_allow_resize(). At that
point memblock_reserve() either succeeds or panics, never returning an
error.

Therefore the return value checks are unreachable, so remove them and the
related logic.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 arch/powerpc/kernel/fadump.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index a313b1653124..88ca6156b81a 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -154,13 +154,8 @@ void __init fadump_append_bootargs(void)
 	if (!fw_dump.dump_active || !fw_dump.param_area_supported || !fw_dump.param_area)
 		return;
 
-	if (fw_dump.param_area < fw_dump.boot_mem_top) {
-		if (memblock_reserve(fw_dump.param_area, COMMAND_LINE_SIZE)) {
-			pr_warn("WARNING: Can't use additional parameters area!\n");
-			fw_dump.param_area = 0;
-			return;
-		}
-	}
+	if (fw_dump.param_area < fw_dump.boot_mem_top)
+		memblock_reserve(fw_dump.param_area, COMMAND_LINE_SIZE);
 
 	append_args = (char *)fw_dump.param_area;
 	len = strlen(boot_command_line);
@@ -632,10 +627,7 @@ int __init fadump_reserve_mem(void)
 		    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
 			goto error_out;
 
-		if (memblock_reserve(base, size)) {
-			pr_err("Failed to reserve memory!\n");
-			goto error_out;
-		}
+		memblock_reserve(base, size);
 
 		pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
 			(size >> 20), base, (memblock_phys_mem_size() >> 20));
-- 
2.43.0

Re: [PATCH 3/5] powerpc/fadump: remove unreachable memblock_reserve() return value checks

[Mukesh Kumar Chaurasiya]

On Wed, Jun 17, 2026 at 03:29:54AM +0900, Sang-Heon Jeon wrote:
> fadump_append_bootargs() and fadump_reserve_mem() both run from
> early_init_devtree(), before it calls memblock_allow_resize(). At that
> point memblock_reserve() either succeeds or panics, never returning an
> error.
> 
> Therefore the return value checks are unreachable, so remove them and the
> related logic.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
> ---
>  arch/powerpc/kernel/fadump.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index a313b1653124..88ca6156b81a 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -154,13 +154,8 @@ void __init fadump_append_bootargs(void)
>  	if (!fw_dump.dump_active || !fw_dump.param_area_supported || !fw_dump.param_area)
>  		return;
>  
> -	if (fw_dump.param_area < fw_dump.boot_mem_top) {
> -		if (memblock_reserve(fw_dump.param_area, COMMAND_LINE_SIZE)) {
> -			pr_warn("WARNING: Can't use additional parameters area!\n");
> -			fw_dump.param_area = 0;
> -			return;
> -		}
> -	}
> +	if (fw_dump.param_area < fw_dump.boot_mem_top)
> +		memblock_reserve(fw_dump.param_area, COMMAND_LINE_SIZE);
>  
>  	append_args = (char *)fw_dump.param_area;
>  	len = strlen(boot_command_line);
> @@ -632,10 +627,7 @@ int __init fadump_reserve_mem(void)
>  		    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
>  			goto error_out;
>  
> -		if (memblock_reserve(base, size)) {
> -			pr_err("Failed to reserve memory!\n");
> -			goto error_out;
> -		}
> +		memblock_reserve(base, size);
>  
>  		pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
>  			(size >> 20), base, (memblock_phys_mem_size() >> 20));
> -- 
> 2.43.0
> 
Yeah, that's a dead code.

Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>