static void bdrv_sync_complete(void *opaque, int ret) { /* do nothing. Masters do not directly interact with the backing store, * only the working copy so no mutexing required. */ }static void flash_sync_page(Flash *s, int page) { if (s->bdrv) { int bdrv_sector, nb_sectors; QEMUIOVector iov; bdrv_sector = (page * s->pi->page_size) / BDRV_SECTOR_SIZE; nb_sectors = DIV_ROUND_UP(s->pi->page_size, BDRV_SECTOR_SIZE); qemu_iovec_init(&iov, 1); qemu_iovec_add(&iov, s->storage + bdrv_sector * BDRV_SECTOR_SIZE, nb_sectors * BDRV_SECTOR_SIZE); bdrv_aio_writev(s->bdrv, bdrv_sector, &iov, nb_sectors, bdrv_sync_complete, NULL); } }
Using AIO is a good idea, but you could have overlapping writes here if you get close calls to flash_sync_page. It can be bad.
Serializing can be done in fancy manners, but it can be as easy as adding bdrv_drain(s->bdrv) before the bdrv_aio_writev.
Paolo
