Re: [PATCH v4 04/11] block-coroutine-wrapper.py: introduce generated_co_wrapper_simple

[Kevin Wolf <kwolf@redhat.com>]

Am 16.11.2022 um 13:22 hat Emanuele Giuseppe Esposito geschrieben:
> This new annotation creates just a function wrapper that creates
> a new coroutine. It assumes the caller is not a coroutine.
> 
> This is much better as g_c_w, because it is clear if the caller
> is a coroutine or not, and provides the advantage of automating
> the code creation. In the future all g_c_w functions will be
> substituted on g_c_w_simple.
> 
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

$ mypy --strict scripts/block-coroutine-wrapper.py
scripts/block-coroutine-wrapper.py:31: error: Function is missing a return type annotation
scripts/block-coroutine-wrapper.py:90: error: Missing type parameters for generic type "Iterator"
scripts/block-coroutine-wrapper.py:110: error: "FuncDecl" has no attribute "co_name"
scripts/block-coroutine-wrapper.py:111: error: "FuncDecl" has no attribute "struct_name"
scripts/block-coroutine-wrapper.py:112: error: "FuncDecl" has no attribute "bs"
scripts/block-coroutine-wrapper.py:135: error: "FuncDecl" has no attribute "co_name"
scripts/block-coroutine-wrapper.py:136: error: "FuncDecl" has no attribute "struct_name"
scripts/block-coroutine-wrapper.py:137: error: "FuncDecl" has no attribute "bs"
scripts/block-coroutine-wrapper.py:160: error: "FuncDecl" has no attribute "co_name"
scripts/block-coroutine-wrapper.py:161: error: "FuncDecl" has no attribute "co_name"
scripts/block-coroutine-wrapper.py:172: error: "FuncDecl" has no attribute "bs"
scripts/block-coroutine-wrapper.py:173: error: "FuncDecl" has no attribute "struct_name"
scripts/block-coroutine-wrapper.py:174: error: "FuncDecl" has no attribute "struct_name"
scripts/block-coroutine-wrapper.py:218: error: Call to untyped function "gen_header" in typed context
Found 14 errors in 1 file (checked 1 source file)

The first two and the last one isn't the fault of this patch, but the
others are. When you add new attributes, they should be declared in
FuncDecl.__init__(). And actually, this even seems like a better place
to initialise them already with the right value than gen_wrapper().

>  include/block/block-common.h       |  1 +
>  scripts/block-coroutine-wrapper.py | 87 ++++++++++++++++++++++--------
>  2 files changed, 66 insertions(+), 22 deletions(-)
> 
> diff --git a/include/block/block-common.h b/include/block/block-common.h
> index 297704c1e9..8ae750c7cf 100644
> --- a/include/block/block-common.h
> +++ b/include/block/block-common.h
> @@ -43,6 +43,7 @@
>   * Read more in docs/devel/block-coroutine-wrapper.rst
>   */
>  #define generated_co_wrapper
> +#define generated_co_wrapper_simple
>  
>  /* block.c */
>  typedef struct BlockDriver BlockDriver;
> diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py
> index 08be813407..f88ef53964 100644
> --- a/scripts/block-coroutine-wrapper.py
> +++ b/scripts/block-coroutine-wrapper.py
> @@ -62,10 +62,15 @@ def __init__(self, param_decl: str) -> None:
>  
>  
>  class FuncDecl:
> -    def __init__(self, return_type: str, name: str, args: str) -> None:
> +    def __init__(self, return_type: str, name: str, args: str,
> +                 variant: str) -> None:
>          self.return_type = return_type.strip()
>          self.name = name.strip()
>          self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
> +        self.create_only_co = False
> +
> +        if variant == '_simple':
> +            self.create_only_co = True
>  
>      def gen_list(self, format: str) -> str:
>          return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
> @@ -75,7 +80,8 @@ def gen_block(self, format: str) -> str:
>  
>  
>  # Match wrappers declared with a generated_co_wrapper mark
> -func_decl_re = re.compile(r'^int\s*generated_co_wrapper\s*'
> +func_decl_re = re.compile(r'^int\s*generated_co_wrapper'
> +                          r'(?P<variant>(_[a-z][a-z0-9_]*)?)\s*'
>                            r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
>                            r'\((?P<args>[^)]*)\);$', re.MULTILINE)
>  
> @@ -84,7 +90,8 @@ def func_decl_iter(text: str) -> Iterator:
>      for m in func_decl_re.finditer(text):
>          yield FuncDecl(return_type='int',
>                         name=m.group('wrapper_name'),
> -                       args=m.group('args'))
> +                       args=m.group('args'),
> +                       variant=m.group('variant'))
>  
>  
>  def snake_to_camel(func_name: str) -> str:
> @@ -97,6 +104,51 @@ def snake_to_camel(func_name: str) -> str:
>      return ''.join(words)
>  
>  
> +# Checks if we are already in coroutine
> +def create_g_c_w(func: FuncDecl) -> str:
> +    name = func.co_name
> +    struct_name = func.struct_name
> +    return f"""\
> +int {func.name}({ func.gen_list('{decl}') })
> +{{
> +    if (qemu_in_coroutine()) {{
> +        return {name}({ func.gen_list('{name}') });
> +    }} else {{
> +        {struct_name} s = {{
> +            .poll_state.bs = {func.bs},
> +            .poll_state.in_progress = true,
> +
> +{ func.gen_block('            .{name} = {name},') }
> +        }};
> +
> +        s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
> +
> +        return bdrv_poll_co(&s.poll_state);
> +    }}
> +}}"""
> +
> +
> +# Assumes we are not in coroutine, and creates one
> +def create_coroutine_only(func: FuncDecl) -> str:
> +    name = func.co_name
> +    struct_name = func.struct_name
> +    return f"""\
> +int {func.name}({ func.gen_list('{decl}') })
> +{{
> +    assert(!qemu_in_coroutine());
> +    {struct_name} s = {{
> +        .poll_state.bs = {func.bs},
> +        .poll_state.in_progress = true,
> +
> +{ func.gen_block('        .{name} = {name},') }
> +    }};

Not sure how strict we are about this in generated code, but generally
the QEMU coding style requires declarations to come first, so the
assertion should be below it.

> +
> +    s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
> +
> +    return bdrv_poll_co(&s.poll_state);
> +}}"""

Kevin