Adding upstream version 1:10.0.2+ds.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

scripts/block-coroutine-wrapper.py

@@ -0,0 +1,323 @@
+#! /usr/bin/env python3
+"""Generate coroutine wrappers for block subsystem.
+
+The program parses one or several concatenated c files from stdin,
+searches for functions with the 'co_wrapper' specifier
+and generates corresponding wrappers on stdout.
+
+Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...
+
+Copyright (c) 2020 Virtuozzo International GmbH.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+
+import sys
+import re
+from typing import Iterator
+
+
+def gen_header():
+    copyright = re.sub('^.*Copyright', 'Copyright', __doc__, flags=re.DOTALL)
+    copyright = re.sub('^(?=.)', ' * ', copyright.strip(), flags=re.MULTILINE)
+    copyright = re.sub('^$', ' *', copyright, flags=re.MULTILINE)
+    return f"""\
+/*
+ * File is generated by scripts/block-coroutine-wrapper.py
+ *
+{copyright}
+ */
+
+#include "qemu/osdep.h"
+#include "block/coroutines.h"
+#include "block/block-gen.h"
+#include "block/block_int.h"
+#include "block/dirty-bitmap.h"
+"""
+
+
+class ParamDecl:
+    param_re = re.compile(r'(?P<decl>'
+                          r'(?P<type>.*[ *])'
+                          r'(?P<name>[a-z][a-z0-9_]*)'
+                          r')')
+
+    def __init__(self, param_decl: str) -> None:
+        m = self.param_re.match(param_decl.strip())
+        if m is None:
+            raise ValueError(f'Wrong parameter declaration: "{param_decl}"')
+        self.decl = m.group('decl')
+        self.type = m.group('type')
+        self.name = m.group('name')
+
+
+class FuncDecl:
+    def __init__(self, wrapper_type: str, return_type: str, name: str,
+                 args: str, variant: str) -> None:
+        self.return_type = return_type.strip()
+        self.name = name.strip()
+        self.struct_name = snake_to_camel(self.name)
+        self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
+        self.create_only_co = 'mixed' not in variant
+        self.graph_rdlock = 'bdrv_rdlock' in variant
+        self.graph_wrlock = 'bdrv_wrlock' in variant
+
+        self.wrapper_type = wrapper_type
+
+        if wrapper_type == 'co':
+            if self.graph_wrlock:
+                raise ValueError(f"co function can't be wrlock: {self.name}")
+            subsystem, subname = self.name.split('_', 1)
+            self.target_name = f'{subsystem}_co_{subname}'
+        else:
+            assert wrapper_type == 'no_co'
+            subsystem, co_infix, subname = self.name.split('_', 2)
+            if co_infix != 'co':
+                raise ValueError(f"Invalid no_co function name: {self.name}")
+            if not self.create_only_co:
+                raise ValueError(f"no_co function can't be mixed: {self.name}")
+            if self.graph_rdlock and self.graph_wrlock:
+                raise ValueError("function can't be both rdlock and wrlock: "
+                                 f"{self.name}")
+            self.target_name = f'{subsystem}_{subname}'
+
+        self.get_result = 's->ret = '
+        self.ret = 'return s.ret;'
+        self.co_ret = 'return '
+        self.return_field = self.return_type + " ret;"
+        if self.return_type == 'void':
+            self.get_result = ''
+            self.ret = ''
+            self.co_ret = ''
+            self.return_field = ''
+
+    def gen_ctx(self, prefix: str = '') -> str:
+        t = self.args[0].type
+        name = self.args[0].name
+        if t == 'BlockDriverState *':
+            return f'bdrv_get_aio_context({prefix}{name})'
+        elif t == 'BdrvChild *':
+            return f'bdrv_get_aio_context({prefix}{name}->bs)'
+        elif t == 'BlockBackend *':
+            return f'blk_get_aio_context({prefix}{name})'
+        else:
+            return 'qemu_get_aio_context()'
+
+    def gen_list(self, format: str) -> str:
+        return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
+
+    def gen_block(self, format: str) -> str:
+        return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)
+
+
+# Match wrappers declared with a co_wrapper mark
+func_decl_re = re.compile(r'^(?P<return_type>[a-zA-Z][a-zA-Z0-9_]* [\*]?)'
+                          r'(\s*coroutine_fn)?'
+                          r'\s*(?P<wrapper_type>(no_)?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)
+
+
+def func_decl_iter(text: str) -> Iterator:
+    for m in func_decl_re.finditer(text):
+        yield FuncDecl(wrapper_type=m.group('wrapper_type'),
+                       return_type=m.group('return_type'),
+                       name=m.group('wrapper_name'),
+                       args=m.group('args'),
+                       variant=m.group('variant'))
+
+
+def snake_to_camel(func_name: str) -> str:
+    """
+    Convert underscore names like 'some_function_name' to camel-case like
+    'SomeFunctionName'
+    """
+    words = func_name.split('_')
+    words = [w[0].upper() + w[1:] for w in words]
+    return ''.join(words)
+
+
+def create_mixed_wrapper(func: FuncDecl) -> str:
+    """
+    Checks if we are already in coroutine
+    """
+    name = func.target_name
+    struct_name = func.struct_name
+    graph_assume_lock = 'assume_graph_lock();' if func.graph_rdlock else ''
+
+    return f"""\
+{func.return_type} {func.name}({ func.gen_list('{decl}') })
+{{
+    if (qemu_in_coroutine()) {{
+        {graph_assume_lock}
+        {func.co_ret}{name}({ func.gen_list('{name}') });
+    }} else {{
+        {struct_name} s = {{
+            .poll_state.ctx = qemu_get_current_aio_context(),
+            .poll_state.in_progress = true,
+
+{ func.gen_block('            .{name} = {name},') }
+        }};
+
+        s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
+
+        bdrv_poll_co(&s.poll_state);
+        {func.ret}
+    }}
+}}"""
+
+
+def create_co_wrapper(func: FuncDecl) -> str:
+    """
+    Assumes we are not in coroutine, and creates one
+    """
+    name = func.target_name
+    struct_name = func.struct_name
+    return f"""\
+{func.return_type} {func.name}({ func.gen_list('{decl}') })
+{{
+    {struct_name} s = {{
+        .poll_state.ctx = qemu_get_current_aio_context(),
+        .poll_state.in_progress = true,
+
+{ func.gen_block('        .{name} = {name},') }
+    }};
+    assert(!qemu_in_coroutine());
+
+    s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
+
+    bdrv_poll_co(&s.poll_state);
+    {func.ret}
+}}"""
+
+
+def gen_co_wrapper(func: FuncDecl) -> str:
+    assert not '_co_' in func.name
+    assert func.wrapper_type == 'co'
+
+    name = func.target_name
+    struct_name = func.struct_name
+
+    graph_lock=''
+    graph_unlock=''
+    if func.graph_rdlock:
+        graph_lock='    bdrv_graph_co_rdlock();'
+        graph_unlock='    bdrv_graph_co_rdunlock();'
+
+    creation_function = create_mixed_wrapper
+    if func.create_only_co:
+        creation_function = create_co_wrapper
+
+    return f"""\
+/*
+ * Wrappers for {name}
+ */
+
+typedef struct {struct_name} {{
+    BdrvPollCo poll_state;
+    {func.return_field}
+{ func.gen_block('    {decl};') }
+}} {struct_name};
+
+static void coroutine_fn {name}_entry(void *opaque)
+{{
+    {struct_name} *s = opaque;
+
+{graph_lock}
+    {func.get_result}{name}({ func.gen_list('s->{name}') });
+{graph_unlock}
+    s->poll_state.in_progress = false;
+
+    aio_wait_kick();
+}}
+
+{creation_function(func)}"""
+
+
+def gen_no_co_wrapper(func: FuncDecl) -> str:
+    assert '_co_' in func.name
+    assert func.wrapper_type == 'no_co'
+
+    name = func.target_name
+    struct_name = func.struct_name
+
+    graph_lock=''
+    graph_unlock=''
+    if func.graph_rdlock:
+        graph_lock='    bdrv_graph_rdlock_main_loop();'
+        graph_unlock='    bdrv_graph_rdunlock_main_loop();'
+    elif func.graph_wrlock:
+        graph_lock='    bdrv_graph_wrlock();'
+        graph_unlock='    bdrv_graph_wrunlock();'
+
+    return f"""\
+/*
+ * Wrappers for {name}
+ */
+
+typedef struct {struct_name} {{
+    Coroutine *co;
+    {func.return_field}
+{ func.gen_block('    {decl};') }
+}} {struct_name};
+
+static void {name}_bh(void *opaque)
+{{
+    {struct_name} *s = opaque;
+
+{graph_lock}
+    {func.get_result}{name}({ func.gen_list('s->{name}') });
+{graph_unlock}
+
+    aio_co_wake(s->co);
+}}
+
+{func.return_type} coroutine_fn {func.name}({ func.gen_list('{decl}') })
+{{
+    {struct_name} s = {{
+        .co = qemu_coroutine_self(),
+{ func.gen_block('        .{name} = {name},') }
+    }};
+    assert(qemu_in_coroutine());
+
+    aio_bh_schedule_oneshot(qemu_get_aio_context(), {name}_bh, &s);
+    qemu_coroutine_yield();
+
+    {func.ret}
+}}"""
+
+
+def gen_wrappers(input_code: str) -> str:
+    res = ''
+    for func in func_decl_iter(input_code):
+        res += '\n\n\n'
+        if func.wrapper_type == 'co':
+            res += gen_co_wrapper(func)
+        else:
+            res += gen_no_co_wrapper(func)
+
+    return res
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 3:
+        exit(f'Usage: {sys.argv[0]} OUT_FILE.c IN_FILE.[ch]...')
+
+    with open(sys.argv[1], 'w', encoding='utf-8') as f_out:
+        f_out.write(gen_header())
+        for fname in sys.argv[2:]:
+            with open(fname, encoding='utf-8') as f_in:
+                f_out.write(gen_wrappers(f_in.read()))
+                f_out.write('\n')