Assertions in the callers of the funciton pointrs are already added by previous patches.
Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> --- include/sysemu/block-backend-common.h | 42 +++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 5 deletions(-) diff --git a/include/sysemu/block-backend-common.h b/include/sysemu/block-backend-common.h index 52ff6a4d26..25f34917b6 100644 --- a/include/sysemu/block-backend-common.h +++ b/include/sysemu/block-backend-common.h @@ -17,6 +17,29 @@ /* Callbacks for block device models */ typedef struct BlockDevOps { + + /* + * Global state (GS) API. These functions run under the BQL lock. + * + * If a function modifies the graph, it also uses drain and/or + * aio_context_acquire/release to be sure it has unique access. + * aio_context locking is needed together with BQL because of + * the thread-safe I/O API that concurrently runs and accesses + * the graph without the BQL. + * + * It is important to note that not all of these functions are + * necessarily limited to running under the BQL, but they would + * require additional auditing and may small thread-safety changes + * to move them into the I/O API. Often it's not worth doing that + * work since the APIs are only used with the BQL held at the + * moment, so they have been placed in the GS API (for now). + * + * All bdrv_* callers that use these function pointers must + * use this assertion: + * g_assert(qemu_in_main_thread()); + * to catch when they are accidentally called without the BQL. + */ + /* * Runs when virtual media changed (monitor commands eject, change) * Argument load is true on load and false on eject. @@ -34,16 +57,25 @@ typedef struct BlockDevOps { * true, even if they do not support eject requests. */ void (*eject_request_cb)(void *opaque, bool force); - /* - * Is the virtual tray open? - * Device models implement this only when the device has a tray. - */ - bool (*is_tray_open)(void *opaque); + /* * Is the virtual medium locked into the device? * Device models implement this only when device has such a lock. */ bool (*is_medium_locked)(void *opaque); + + /* + * I/O API functions. These functions are thread-safe, and therefore + * can run in any thread as long as they have called + * aio_context_acquire/release(). + */ + + /* + * Is the virtual tray open? + * Device models implement this only when the device has a tray. + */ + bool (*is_tray_open)(void *opaque); + /* * Runs when the size changed (e.g. monitor command block_resize) */ -- 2.27.0