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bh=6l0SO/qc8S87CMPkxkvCmqoIgdVpfQDzR9iFjsJDdLE=; b=JJVEswpa5gTjvuwxbSAym7q7HCBCBIgDOyOvQLlE47fc6FEPqB/4LMMiIGZKYdcoM8TplM gInvQL5YTnZUqbWmew5ABeUqgy5ersPEF+tJGBaGlvrdA7aoIw0L6d3GqPXS9OUf7zJh27 gL7WYMgLc0gOrSkwH+vYurHR1SFM9yU= X-MC-Unique: F7exgi21MyyfYF8y1Y5vjg-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, hreitz@redhat.com, eesposit@redhat.com, pbonzini@redhat.com, vsementsov@yandex-team.ru, qemu-devel@nongnu.org Subject: [PATCH 13/18] block: assert that graph read and writes are performed correctly Date: Wed, 7 Dec 2022 14:18:33 +0100 Message-Id: <20221207131838.239125-14-kwolf@redhat.com> In-Reply-To: <20221207131838.239125-1-kwolf@redhat.com> References: <20221207131838.239125-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1670419386990100003 Content-Type: text/plain; charset="utf-8" From: Emanuele Giuseppe Esposito Remove the old assert_bdrv_graph_writable, and replace it with the new version using graph-lock API. See the function documentation for more information. Signed-off-by: Emanuele Giuseppe Esposito Signed-off-by: Kevin Wolf --- include/block/block_int-global-state.h | 17 ----------------- include/block/graph-lock.h | 15 +++++++++++++++ block.c | 4 ++-- block/graph-lock.c | 11 +++++++++++ 4 files changed, 28 insertions(+), 19 deletions(-) diff --git a/include/block/block_int-global-state.h b/include/block/block_i= nt-global-state.h index b49f4eb35b..2f0993f6e9 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -310,21 +310,4 @@ void bdrv_remove_aio_context_notifier(BlockDriverState= *bs, */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); =20 -/** - * Make sure that the function is running under both drain and BQL. - * The latter protects from concurrent writings - * from the GS API, while the former prevents concurrent reads - * from I/O. - */ -static inline void assert_bdrv_graph_writable(BlockDriverState *bs) -{ - /* - * TODO: this function is incomplete. Because the users of this - * assert lack the necessary drains, check only for BQL. - * Once the necessary drains are added, - * assert also for qatomic_read(&bs->quiesce_counter) > 0 - */ - assert(qemu_in_main_thread()); -} - #endif /* BLOCK_INT_GLOBAL_STATE_H */ diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index b27d8a5fb1..85e8a53b73 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -135,6 +135,21 @@ void coroutine_fn bdrv_graph_co_rdunlock(void); void bdrv_graph_rdlock_main_loop(void); void bdrv_graph_rdunlock_main_loop(void); =20 +/* + * assert_bdrv_graph_readable: + * Make sure that the reader is either the main loop, + * or there is at least a reader helding the rdlock. + * In this way an incoming writer is aware of the read and waits. + */ +void assert_bdrv_graph_readable(void); + +/* + * assert_bdrv_graph_writable: + * Make sure that the writer is the main loop and has set @has_writer, + * so that incoming readers will pause. + */ +void assert_bdrv_graph_writable(void); + typedef struct GraphLockable { } GraphLockable; =20 /* diff --git a/block.c b/block.c index bdffadcdaa..ff53b41af3 100644 --- a/block.c +++ b/block.c @@ -1406,7 +1406,7 @@ static void bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs =3D child->opaque; =20 - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_INSERT_HEAD(&bs->children, child, next); if (bs->drv->is_filter || (child->role & BDRV_CHILD_FILTERED)) { /* @@ -1452,7 +1452,7 @@ static void bdrv_child_cb_detach(BdrvChild *child) bdrv_backing_detach(child); } =20 - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_REMOVE(child, next); if (child =3D=3D bs->backing) { assert(child !=3D bs->file); diff --git a/block/graph-lock.c b/block/graph-lock.c index e033c6d9ac..c4d9d2c274 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -259,3 +259,14 @@ void bdrv_graph_rdunlock_main_loop(void) GLOBAL_STATE_CODE(); assert(!qemu_in_coroutine()); } + +void assert_bdrv_graph_readable(void) +{ + assert(qemu_in_main_thread() || reader_count()); +} + +void assert_bdrv_graph_writable(void) +{ + assert(qemu_in_main_thread()); + assert(qatomic_read(&has_writer)); +} --=20 2.38.1