Re: [PATCH 14/29] block/export: Move AioContext from NBDExport to BlockExport

[Max Reitz]

On 07.09.20 20:19, Kevin Wolf wrote:
> Signed-off-by: Kevin Wolf 
> ---
>  include/block/export.h |  3 +++
>  block/export/export.c  |  2 ++
>  nbd/server.c   | 26 +-
>  3 files changed, 18 insertions(+), 13 deletions(-)

Reviewed-by: Max Reitz 



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[PATCH 14/29] block/export: Move AioContext from NBDExport to BlockExport

[Kevin Wolf]

Signed-off-by: Kevin Wolf 
---
 include/block/export.h |  3 +++
 block/export/export.c  |  2 ++
 nbd/server.c   | 26 +-
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/include/block/export.h b/include/block/export.h
index 5236a35e12..e6f96f4e1e 100644
--- a/include/block/export.h
+++ b/include/block/export.h
@@ -41,6 +41,9 @@ struct BlockExport {
  * the export.
  */
 int refcount;
+
+/* The AioContext whose lock protects this BlockExport object. */
+AioContext *ctx;
 };
 
 BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp);
diff --git a/block/export/export.c b/block/export/export.c
index baba4e94ff..8635318ef1 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -49,12 +49,14 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error 
**errp)
 return drv->create(export, errp);
 }
 
+/* Callers must hold exp->ctx lock */
 void blk_exp_ref(BlockExport *exp)
 {
 assert(exp->refcount > 0);
 exp->refcount++;
 }
 
+/* Callers must hold exp->ctx lock */
 void blk_exp_unref(BlockExport *exp)
 {
 assert(exp->refcount > 0);
diff --git a/nbd/server.c b/nbd/server.c
index 7be81c7bda..7cf81646fc 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -92,8 +92,6 @@ struct NBDExport {
 QTAILQ_HEAD(, NBDClient) clients;
 QTAILQ_ENTRY(NBDExport) next;
 
-AioContext *ctx;
-
 BlockBackend *eject_notifier_blk;
 Notifier eject_notifier;
 
@@ -1333,8 +1331,8 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, 
Error **errp)
 }
 
 /* Attach the channel to the same AioContext as the export */
-if (client->exp && client->exp->ctx) {
-qio_channel_attach_aio_context(client->ioc, client->exp->ctx);
+if (client->exp && client->exp->common.ctx) {
+qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx);
 }
 
 assert(!client->optlen);
@@ -1466,7 +1464,7 @@ static void blk_aio_attached(AioContext *ctx, void 
*opaque)
 
 trace_nbd_blk_aio_attached(exp->name, ctx);
 
-exp->ctx = ctx;
+exp->common.ctx = ctx;
 
 QTAILQ_FOREACH(client, >clients, next) {
 qio_channel_attach_aio_context(client->ioc, ctx);
@@ -1484,13 +1482,13 @@ static void blk_aio_detach(void *opaque)
 NBDExport *exp = opaque;
 NBDClient *client;
 
-trace_nbd_blk_aio_detach(exp->name, exp->ctx);
+trace_nbd_blk_aio_detach(exp->name, exp->common.ctx);
 
 QTAILQ_FOREACH(client, >clients, next) {
 qio_channel_detach_aio_context(client->ioc);
 }
 
-exp->ctx = NULL;
+exp->common.ctx = NULL;
 }
 
 static void nbd_eject_notifier(Notifier *n, void *data)
@@ -1498,7 +1496,7 @@ static void nbd_eject_notifier(Notifier *n, void *data)
 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
 AioContext *aio_context;
 
-aio_context = exp->ctx;
+aio_context = exp->common.ctx;
 aio_context_acquire(aio_context);
 nbd_export_close(exp);
 aio_context_release(aio_context);
@@ -1535,10 +1533,13 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
 return NULL;
 }
 
+ctx = bdrv_get_aio_context(bs);
+
 exp = g_new0(NBDExport, 1);
 exp->common = (BlockExport) {
 .drv= _exp_nbd,
 .refcount   = 1,
+.ctx= ctx,
 };
 
 /*
@@ -1548,7 +1549,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
  * ctx was acquired in the caller.
  */
 assert(name && strlen(name) <= NBD_MAX_STRING_SIZE);
-ctx = bdrv_get_aio_context(bs);
+
 bdrv_invalidate_cache(bs, NULL);
 
 /* Don't allow resize while the NBD server is running, otherwise we don't
@@ -1622,7 +1623,6 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
 assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE);
 }
 
-exp->ctx = ctx;
 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
 
 blk_exp_ref(>common);
@@ -1653,7 +1653,7 @@ NBDExport *nbd_export_find(const char *name)
 AioContext *
 nbd_export_aio_context(NBDExport *exp)
 {
-return exp->ctx;
+return exp->common.ctx;
 }
 
 void nbd_export_close(NBDExport *exp)
@@ -1738,7 +1738,7 @@ void nbd_export_close_all(void)
 AioContext *aio_context;
 
 QTAILQ_FOREACH_SAFE(exp, , next, next) {
-aio_context = exp->ctx;
+aio_context = exp->common.ctx;
 aio_context_acquire(aio_context);
 nbd_export_close(exp);
 aio_context_release(aio_context);
@@ -2537,7 +2537,7 @@ static void nbd_client_receive_next_request(NBDClient 
*client)
 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
 nbd_client_get(client);
 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
-aio_co_schedule(client->exp->ctx, client->recv_coroutine);
+aio_co_schedule(client->exp->common.ctx, client->recv_coroutine);
 }
 }
 
-- 
2.25.4