Re: [PATCH v2] iommu/generic_pt: use __always_inline for amdv1pt_install_leaf_entry()

[Jason Gunthorpe <jgg@ziepe.ca>]

On Thu, Apr 09, 2026 at 08:01:17PM +0300, Konstantin Khorenko wrote:
> With -fprofile-update=atomic in CFLAGS_GCOV, GCC fails to eliminate
> an impossible branch in FIELD_PREP() inside amdv1pt_install_leaf_entry()
> when the function is merely "static inline".  GCC may choose not to
> inline it, and without seeing the constant arguments at the call site
> it cannot prove the FIELD_PREP value fits the field.
> 
> Change from "static inline" to "static __always_inline" so GCC is
> forced to inline the function and can see the constant values,
> allowing dead code elimination of the impossible branch.
> 
> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
> ---
>  drivers/iommu/generic_pt/fmt/amdv1.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

It was already merged:

commit 8b72aa5704c77380742346d4ac755b074b7f9eaa
Author: Sherry Yang <sherry.yang@oracle.com>
Date:   Thu Mar 26 09:17:19 2026 -0700

    iommupt/amdv1: mark amdv1pt_install_leaf_entry as __always_inline
    
    After enabling CONFIG_GCOV_KERNEL and CONFIG_GCOV_PROFILE_ALL, following
    build failure is observed under GCC 14.2.1: