Re: [PATCH v4 3/3] xen/efi: Update error flow for read_file function

[Frediano Ziglio <frediano.ziglio@xxxxxxxxx>]

On Thu, Jun 26, 2025 at 3:50 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 26.06.2025 15:41, Frediano Ziglio wrote:
> > On Thu, Jun 26, 2025 at 2:31 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
> >>
> >> On 26.06.2025 15:10, Frediano Ziglio wrote:
> >>> --- a/xen/common/efi/boot.c
> >>> +++ b/xen/common/efi/boot.c
> >>> @@ -792,6 +792,8 @@ static bool __init read_file(EFI_FILE_HANDLE 
> >>> dir_handle, CHAR16 *name,
> >>>
> >>>      if ( !name )
> >>>          PrintErrMesg(L"No filename", EFI_OUT_OF_RESOURCES);
> >>> +
> >>> +    what = L"Open";
> >>>      if ( dir_handle )
> >>>          ret = dir_handle->Open(dir_handle, &FileHandle, name,
> >>>                                 EFI_FILE_MODE_READ, 0);
> >>> @@ -800,54 +802,58 @@ static bool __init read_file(EFI_FILE_HANDLE 
> >>> dir_handle, CHAR16 *name,
> >>>      if ( file == &cfg && ret == EFI_NOT_FOUND )
> >>>          return false;
> >>>      if ( EFI_ERROR(ret) )
> >>> -        what = L"Open";
> >>> -    else
> >>> -        ret = FileHandle->SetPosition(FileHandle, -1);
> >>> +        goto fail;
> >>> +
> >>> +    what = L"Seek";
> >>> +    ret = FileHandle->SetPosition(FileHandle, -1);
> >>>      if ( EFI_ERROR(ret) )
> >>> -        what = what ?: L"Seek";
> >>> -    else
> >>> -        ret = FileHandle->GetPosition(FileHandle, &size);
> >>> +        goto fail;
> >>> +
> >>> +    what = L"Get size";
> >>> +    ret = FileHandle->GetPosition(FileHandle, &size);
> >>>      if ( EFI_ERROR(ret) )
> >>> -        what = what ?: L"Get size";
> >>> -    else
> >>> -        ret = FileHandle->SetPosition(FileHandle, 0);
> >>> +        goto fail;
> >>> +
> >>> +    what = L"Seek";
> >>> +    ret = FileHandle->SetPosition(FileHandle, 0);
> >>>      if ( EFI_ERROR(ret) )
> >>> -        what = what ?: L"Seek";
> >>> -    else
> >>> -    {
> >>> -        file->addr = min(1UL << (32 + PAGE_SHIFT),
> >>> -                         HYPERVISOR_VIRT_END - DIRECTMAP_VIRT_START);
> >>> -        ret = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
> >>> -                                    PFN_UP(size), &file->addr);
> >>> -    }
> >>> +        goto fail;
> >>> +
> >>> +    what = L"Allocation";
> >>> +    file->addr = min(1UL << (32 + PAGE_SHIFT),
> >>> +                     HYPERVISOR_VIRT_END - DIRECTMAP_VIRT_START);
> >>> +    ret = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
> >>> +                                PFN_UP(size), &file->addr);
> >>>      if ( EFI_ERROR(ret) )
> >>> -        what = what ?: L"Allocation";
> >>> -    else
> >>> -    {
> >>> -        file->need_to_free = true;
> >>> -        file->size = size;
> >>> -        handle_file_info(name, file, options);
> >>> +        goto fail;
> >>>
> >>> -        ret = FileHandle->Read(FileHandle, &file->size, file->str);
> >>> -        if ( !EFI_ERROR(ret) && file->size != size )
> >>> -            ret = EFI_ABORTED;
> >>> -        if ( EFI_ERROR(ret) )
> >>> -            what = L"Read";
> >>> -    }
> >>> +    file->need_to_free = true;
> >>> +    file->size = size;
> >>> +    handle_file_info(name, file, options);
> >>>
> >>> -    if ( FileHandle )
> >>> -        FileHandle->Close(FileHandle);
> >>> +    what = L"Read";
> >>> +    ret = FileHandle->Read(FileHandle, &file->size, file->str);
> >>> +    if ( !EFI_ERROR(ret) && file->size != size )
> >>> +        ret = EFI_ABORTED;
> >>> +    if ( EFI_ERROR(ret) )
> >>> +        goto fail;
> >>>
> >>> -    if ( what )
> >>> -    {
> >>> -        PrintErr(what);
> >>> -        PrintErr(L" failed for ");
> >>> -        PrintErrMesg(name, ret);
> >>> -    }
> >>> +    FileHandle->Close(FileHandle);
> >>>
> >>>      efi_arch_flush_dcache_area(file->ptr, file->size);
> >>>
> >>>      return true;
> >>> +
> >>> +fail:
> >>
> >> Nit: Style (see ./CODING_STYLE).
> >>
> >
> > What specifically? I checked the indentation and it's 4 spaces. if-s
> > are spaced correctly. About labels I didn't find much on CODING_STYLE
> > so I opened 3/4 files and most of them are indented with no spaces
> > (they start at column 1).
>
> You didn't search for the word "label" then, did you? Quote:
>

I did, I probably mis-typed it.

> 'Due to the behavior of GNU diffutils "diff -p", labels should be
>  indented by at least one blank.  Non-case labels inside switch() bodies
>  are preferred to be indented the same as the block's case labels.'
>

I suppose labels should be indented less than the code they refer to,
so in this case from 1 to 3 spaces. I supposed 2 would be the best
option.

> Jan
>