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2023-02-17block-coroutine-wrapper: Introduce no_co_wrapperKevin Wolf
Some functions must not be called from coroutine context. The common pattern to use them anyway from a coroutine is running them in a BH and letting the calling coroutine yield to be woken up when the BH is completed. Instead of manually writing such wrappers, add support for generating them to block-coroutine-wrapper. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230126172432.436111-2-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block-coroutine-wrapper: support void functionsEmanuele Giuseppe Esposito
Just omit the various 'return' when the return type is void. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-2-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-01-20include/block: Untangle inclusion loopsMarkus Armbruster
We have two inclusion loops: block/block.h -> block/block-global-state.h -> block/block-common.h -> block/blockjob.h -> block/block.h block/block.h -> block/block-io.h -> block/block-common.h -> block/blockjob.h -> block/block.h I believe these go back to Emanuele's reorganization of the block API, merged a few months ago in commit d7e2fe4aac8. Fortunately, breaking them is merely a matter of deleting unnecessary includes from headers, and adding them back in places where they are now missing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20221221133551.3967339-2-armbru@redhat.com>
2022-12-15block-coroutine-wrapper.py: introduce annotations that take the graph rdlockEmanuele Giuseppe Esposito
Add co_wrapper_bdrv_rdlock and co_wrapper_mixed_bdrv_rdlock option to the block-coroutine-wrapper.py script. This "_bdrv_rdlock" option takes and releases the graph rdlock when a coroutine function is created. This means that when used together with "_mixed", the function marked with co_wrapper_mixed_bdrv_rdlock will support both coroutine and non-coroutine case, and in the latter case it will create a coroutine that takes and releases the rdlock. When called from a coroutine, the caller must already hold the graph lock. Example: void co_wrapper_mixed_bdrv_rdlock bdrv_f1(); Becomes static void bdrv_co_enter_f1() { bdrv_graph_co_rdlock(); bdrv_co_function(); bdrv_graph_co_rdunlock(); } void bdrv_f1() { if (qemu_in_coroutine) { assume_graph_lock(); bdrv_co_function(); } else { qemu_co_enter(bdrv_co_enter_f1); ... } } When used alone, the function will not work in coroutine context, and when called in non-coroutine context it will create a new coroutine that takes care of taking and releasing the rdlock automatically. Example: void co_wrapper_bdrv_rdlock bdrv_f1(); Becomes static void bdrv_co_enter_f1() { bdrv_graph_co_rdlock(); bdrv_co_function(); bdrv_graph_co_rdunlock(); } void bdrv_f1() { assert(!qemu_in_coroutine()); qemu_co_enter(bdrv_co_enter_f1); ... } About their usage: - co_wrapper does not take the rdlock, so it can be used also outside the block layer. - co_wrapper_mixed will be used by many blk_* functions, since the coroutine function needs to call blk_wait_while_drained() and the rdlock *must* be taken afterwards, otherwise it's a deadlock. In the future this annotation will go away, and blk_* will use co_wrapper directly. - co_wrapper_bdrv_rdlock will be used by BlockDriver callbacks, ideally by all of them in the future. - co_wrapper_mixed_bdrv_rdlock will be used by the remaining functions that are still called by coroutine and non-coroutine context. In the future this annotation will go away, as we will split such mixed functions. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20221207131838.239125-17-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15block-coroutine-wrapper.py: support also basic return typesEmanuele Giuseppe Esposito
Extend the regex to cover also return type, pointers included. This implies that the value returned by the function cannot be a simple "int" anymore, but the custom return type. Therefore remove poll_state->ret and instead use a per-function custom "ret" field. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-13-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15block-coroutine-wrapper.py: support functions without bs argEmanuele Giuseppe Esposito
Right now, we take the first parameter of the function to get the BlockDriverState to pass to bdrv_poll_co(), that internally calls functions that figure in which aiocontext the coroutine should run. However, it is useless to pass a bs just to get its own AioContext, so instead pass it directly, and default to the main loop if no BlockDriverState is passed as parameter. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-12-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15block-coroutine-wrapper.py: introduce co_wrapperEmanuele Giuseppe Esposito
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>
2022-12-15block: rename generated_co_wrapper in co_wrapper_mixedEmanuele Giuseppe Esposito
In preparation to the incoming new function specifiers, rename g_c_w with a more meaningful name and document it. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-10-eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-10-15block-coroutine-wrapper.py: support BlockBackend first argumentVladimir Sementsov-Ogievskiy
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20211006131718.214235-7-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18block-coroutine-wrapper: allow non bdrv_ prefixVladimir Sementsov-Ogievskiy
We are going to reuse the script to generate a nbd_ function in further commit. Prepare the script now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-28-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-05scripts: add block-coroutine-wrapper.pyVladimir Sementsov-Ogievskiy
We have a very frequent pattern of creating a coroutine from a function with several arguments: - create a structure to pack parameters - create _entry function to call original function taking parameters from struct - do different magic to handle completion: set ret to NOT_DONE or EINPROGRESS or use separate bool field - fill the struct and create coroutine from _entry function with this struct as a parameter - do coroutine enter and BDRV_POLL_WHILE loop Let's reduce code duplication by generating coroutine wrappers. This patch adds scripts/block-coroutine-wrapper.py together with some friends, which will generate functions with declared prototypes marked by the 'generated_co_wrapper' specifier. The usage of new code generation is as follows: 1. define the coroutine function somewhere int coroutine_fn bdrv_co_NAME(...) {...} 2. declare in some header file int generated_co_wrapper bdrv_NAME(...); with same list of parameters (generated_co_wrapper is defined in "include/block/block.h"). 3. Make sure the block_gen_c declaration in block/meson.build mentions the file with your marker function. Still, no function is now marked, this work is for the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200924185414.28642-5-vsementsov@virtuozzo.com> [Added encoding='utf-8' to open() calls as requested by Vladimir. Fixed typo and grammar issues pointed out by Eric Blake. Removed clang-format dependency that caused build test issues. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>