Track the IOThreads used by a block export and identify the holder with the unique BlockExportOptions id.
Acquire holder-aware references during export creation and release them on error or export deletion. Support both single- and multi-iothread exports. Reviewed-by: Stefan Hajnoczi <[email protected]> Signed-off-by: Zhang Chen <[email protected]> --- block/export/export.c | 62 ++++++++++++++++++++++++++++++++++++------ include/block/export.h | 5 ++++ 2 files changed, 58 insertions(+), 9 deletions(-) diff --git a/block/export/export.c b/block/export/export.c index b733f269f3..0e019545ef 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -15,7 +15,6 @@ #include "block/block.h" #include "system/block-backend.h" -#include "system/iothread.h" #include "block/export.h" #include "block/fuse.h" #include "block/nbd.h" @@ -72,6 +71,32 @@ static const BlockExportDriver *blk_exp_find_driver(BlockExportType type) return NULL; } +static void init_iothreads(const char *holder_id, IOThread **iothreads, + size_t num_iothreads, AioContext **aio_ctxs) +{ + const IOThreadHolder holder = { + .type = IO_THREAD_HOLDER_KIND_BLOCK_EXPORT, + .u.block_export.export_id = (char *)holder_id, + }; + + for (size_t i = 0; i < num_iothreads; i++) { + aio_ctxs[i] = iothread_ref_and_get_aio_context(iothreads[i], &holder); + } +} + +static void cleanup_iothreads(const char *holder_id, IOThread **iothreads, + size_t num_iothreads) +{ + const IOThreadHolder holder = { + .type = IO_THREAD_HOLDER_KIND_BLOCK_EXPORT, + .u.block_export.export_id = (char *)holder_id, + }; + + for (size_t i = 0; i < num_iothreads; i++) { + iothread_unref_and_put_aio_context(iothreads[i], &holder); + } +} + BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) { bool fixed_iothread = export->has_fixed_iothread && export->fixed_iothread; @@ -85,6 +110,8 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) AioContext *ctx; AioContext **multithread_ctxs = NULL; size_t multithread_count = 0; + g_autofree IOThread **local_iothreads = NULL; + size_t iothread_count = 0; uint64_t perm; int ret; @@ -139,7 +166,10 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) goto fail; } - new_ctx = iothread_get_aio_context(iothread); + local_iothreads = g_new0(IOThread *, 1); + local_iothreads[0] = iothread; + init_iothreads(export->id, local_iothreads, 1, &new_ctx); + iothread_count = 1; /* Ignore errors with fixed-iothread=false */ set_context_errp = fixed_iothread ? errp : NULL; @@ -163,8 +193,10 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return NULL; } + local_iothreads = g_new0(IOThread *, multithread_count); multithread_ctxs = g_new(AioContext *, multithread_count); i = 0; + for (strList *e = iothread_list; e; e = e->next) { IOThread *iothread = iothread_by_id(e->value); @@ -172,9 +204,12 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) error_setg(errp, "iothread \"%s\" not found", e->value); goto fail; } - multithread_ctxs[i++] = iothread_get_aio_context(iothread); + local_iothreads[i++] = iothread; } assert(i == multithread_count); + init_iothreads(export->id, local_iothreads, multithread_count, + multithread_ctxs); + iothread_count = multithread_count; } bdrv_graph_rdlock_main_loop(); @@ -225,12 +260,14 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) assert(drv->instance_size >= sizeof(BlockExport)); exp = g_malloc0(drv->instance_size); *exp = (BlockExport) { - .drv = drv, - .refcount = 1, - .user_owned = true, - .id = g_strdup(export->id), - .ctx = ctx, - .blk = blk, + .drv = drv, + .refcount = 1, + .user_owned = true, + .id = g_strdup(export->id), + .ctx = ctx, + .blk = blk, + .iothreads = g_steal_pointer(&local_iothreads), + .iothread_count = iothread_count, }; ret = drv->create(exp, export, multithread_ctxs, multithread_count, errp); @@ -250,8 +287,12 @@ fail: blk_unref(blk); } if (exp) { + cleanup_iothreads(exp->id, exp->iothreads, exp->iothread_count); + g_free(exp->iothreads); g_free(exp->id); g_free(exp); + } else { + cleanup_iothreads(export->id, local_iothreads, iothread_count); } g_free(multithread_ctxs); return NULL; @@ -273,6 +314,9 @@ static void blk_exp_delete_bh(void *opaque) exp->drv->delete(exp); blk_set_dev_ops(exp->blk, NULL, NULL); blk_unref(exp->blk); + + cleanup_iothreads(exp->id, exp->iothreads, exp->iothread_count); + g_free(exp->iothreads); qapi_event_send_block_export_deleted(exp->id); g_free(exp->id); g_free(exp); diff --git a/include/block/export.h b/include/block/export.h index ca45da928c..ce8e4eb604 100644 --- a/include/block/export.h +++ b/include/block/export.h @@ -16,6 +16,7 @@ #include "qapi/qapi-types-block-export.h" #include "qemu/queue.h" +#include "system/iothread.h" typedef struct BlockExport BlockExport; @@ -89,6 +90,10 @@ struct BlockExport { /* List entry for block_exports */ QLIST_ENTRY(BlockExport) next; + + /* The IOThreads utilized by this specific block export */ + IOThread **iothreads; + size_t iothread_count; }; BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp); -- 2.43.0
