block-coroutine-wrapper.py: introduce co_wrapper

This new annotation starts just a function wrapper that creates
a new coroutine. It assumes the caller is not a coroutine.
It will be the default annotation to be used in the future.

This is much better as c_w_mixed, 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 c_w_mixed functions will be
substituted by co_wrapper.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20221128142337.657646-11-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Emanuele Giuseppe Esposito 2022-11-28 09:23:33 -05:00 committed by Kevin Wolf
parent 1bd542016c
commit 76a2f554c1
3 changed files with 86 additions and 38 deletions

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@ -26,12 +26,12 @@ called ``bdrv_foo(<same args>)``. In this case the script can help. To
trigger the generation: trigger the generation:
1. You need ``bdrv_foo`` declaration somewhere (for example, in 1. You need ``bdrv_foo`` declaration somewhere (for example, in
``block/coroutines.h``) with the ``co_wrapper_mixed`` mark, ``block/coroutines.h``) with the ``co_wrapper`` mark,
like this: like this:
.. code-block:: c .. code-block:: c
int co_wrapper_mixed bdrv_foo(<some args>); int co_wrapper bdrv_foo(<some args>);
2. You need to feed this declaration to block-coroutine-wrapper script. 2. You need to feed this declaration to block-coroutine-wrapper script.
For this, add the .h (or .c) file with the declaration to the For this, add the .h (or .c) file with the declaration to the
@ -46,7 +46,7 @@ Links
1. The script location is ``scripts/block-coroutine-wrapper.py``. 1. The script location is ``scripts/block-coroutine-wrapper.py``.
2. Generic place for private ``co_wrapper_mixed`` declarations is 2. Generic place for private ``co_wrapper`` declarations is
``block/coroutines.h``, for public declarations: ``block/coroutines.h``, for public declarations:
``include/block/block.h`` ``include/block/block.h``

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@ -42,9 +42,13 @@
* *
* Usage: read docs/devel/block-coroutine-wrapper.rst * Usage: read docs/devel/block-coroutine-wrapper.rst
* *
* co_wrapper_mixed functions can be called by both coroutine and * There are 2 kind of specifiers:
* - co_wrapper functions can be called by only non-coroutine context, because
* they always generate a new coroutine.
* - co_wrapper_mixed functions can be called by both coroutine and
* non-coroutine context. * non-coroutine context.
*/ */
#define co_wrapper
#define co_wrapper_mixed #define co_wrapper_mixed
/* block.c */ /* block.c */

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@ -2,7 +2,7 @@
"""Generate coroutine wrappers for block subsystem. """Generate coroutine wrappers for block subsystem.
The program parses one or several concatenated c files from stdin, The program parses one or several concatenated c files from stdin,
searches for functions with the 'co_wrapper_mixed' specifier searches for functions with the 'co_wrapper' specifier
and generates corresponding wrappers on stdout. and generates corresponding wrappers on stdout.
Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]... Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...
@ -62,10 +62,25 @@ class ParamDecl:
class FuncDecl: 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.return_type = return_type.strip()
self.name = name.strip() self.name = name.strip()
self.struct_name = snake_to_camel(self.name)
self.args = [ParamDecl(arg.strip()) for arg in args.split(',')] self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
self.create_only_co = 'mixed' not in variant
subsystem, subname = self.name.split('_', 1)
self.co_name = f'{subsystem}_co_{subname}'
t = self.args[0].type
if t == 'BlockDriverState *':
bs = 'bs'
elif t == 'BdrvChild *':
bs = 'child->bs'
else:
bs = 'blk_bs(blk)'
self.bs = bs
def gen_list(self, format: str) -> str: def gen_list(self, format: str) -> str:
return ', '.join(format.format_map(arg.__dict__) for arg in self.args) return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
@ -74,8 +89,9 @@ class FuncDecl:
return '\n'.join(format.format_map(arg.__dict__) for arg in self.args) return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)
# Match wrappers declared with a co_wrapper_mixed mark # Match wrappers declared with a co_wrapper mark
func_decl_re = re.compile(r'^int\s*co_wrapper_mixed\s*' func_decl_re = re.compile(r'^int\s*co_wrapper'
r'(?P<variant>(_[a-z][a-z0-9_]*)?)\s*'
r'(?P<wrapper_name>[a-z][a-z0-9_]*)' r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
r'\((?P<args>[^)]*)\);$', re.MULTILINE) r'\((?P<args>[^)]*)\);$', re.MULTILINE)
@ -84,7 +100,8 @@ def func_decl_iter(text: str) -> Iterator:
for m in func_decl_re.finditer(text): for m in func_decl_re.finditer(text):
yield FuncDecl(return_type='int', yield FuncDecl(return_type='int',
name=m.group('wrapper_name'), 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: def snake_to_camel(func_name: str) -> str:
@ -97,24 +114,67 @@ def snake_to_camel(func_name: str) -> str:
return ''.join(words) return ''.join(words)
def create_mixed_wrapper(func: FuncDecl) -> str:
"""
Checks if we are already in coroutine
"""
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);
}}
}}"""
def create_co_wrapper(func: FuncDecl) -> str:
"""
Assumes we are not in coroutine, and creates one
"""
name = func.co_name
struct_name = func.struct_name
return f"""\
int {func.name}({ func.gen_list('{decl}') })
{{
{struct_name} s = {{
.poll_state.bs = {func.bs},
.poll_state.in_progress = true,
{ func.gen_block(' .{name} = {name},') }
}};
assert(!qemu_in_coroutine());
s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
return bdrv_poll_co(&s.poll_state);
}}"""
def gen_wrapper(func: FuncDecl) -> str: def gen_wrapper(func: FuncDecl) -> str:
assert not '_co_' in func.name assert not '_co_' in func.name
assert func.return_type == 'int' assert func.return_type == 'int'
assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *', assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *',
'BlockBackend *'] 'BlockBackend *']
subsystem, subname = func.name.split('_', 1) name = func.co_name
struct_name = func.struct_name
name = f'{subsystem}_co_{subname}' creation_function = create_mixed_wrapper
if func.create_only_co:
t = func.args[0].type creation_function = create_co_wrapper
if t == 'BlockDriverState *':
bs = 'bs'
elif t == 'BdrvChild *':
bs = 'child->bs'
else:
bs = 'blk_bs(blk)'
struct_name = snake_to_camel(name)
return f"""\ return f"""\
/* /*
@ -136,23 +196,7 @@ static void coroutine_fn {name}_entry(void *opaque)
aio_wait_kick(); aio_wait_kick();
}} }}
int {func.name}({ func.gen_list('{decl}') }) {creation_function(func)}"""
{{
if (qemu_in_coroutine()) {{
return {name}({ func.gen_list('{name}') });
}} else {{
{struct_name} s = {{
.poll_state.bs = {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);
}}
}}"""
def gen_wrappers(input_code: str) -> str: def gen_wrappers(input_code: str) -> str: