On 12/11/2021 13:25, Hanna Reitz wrote:
On 25.10.21 12:17, Emanuele Giuseppe Esposito wrote:
block.h currently contains a mix of functions:
some of them run under the BQL and modify the block layer graph,
others are instead thread-safe and perform I/O in iothreads.
It is not easy to understand which function is part of which
group (I/O vs GS), and this patch aims to clarify it.
The "GS" functions need the BQL, and often use
aio_context_acquire/release and/or drain to be sure they
can modify the graph safely.
The I/O function are instead thread safe, and can run in
any AioContext.
By splitting the header in two files, block-io.h
and block-global-state.h we have a clearer view on what
needs what kind of protection. block-common.h
contains common structures shared by both headers.
block.h is left there for legacy and to avoid changing
all includes in all c files that use the block APIs.
Assertions are added in the next patch.
Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block.c | 3 +
block/meson.build | 7 +-
include/block/block-common.h | 389 +++++++++++++
include/block/block-global-state.h | 286 ++++++++++
include/block/block-io.h | 306 ++++++++++
include/block/block.h | 878 +----------------------------
6 files changed, 1012 insertions(+), 857 deletions(-)
create mode 100644 include/block/block-common.h
create mode 100644 include/block/block-global-state.h
create mode 100644 include/block/block-io.h
[...]
diff --git a/include/block/block-common.h b/include/block/block-common.h
new file mode 100644
index 0000000000..4f1fd8de21
--- /dev/null
+++ b/include/block/block-common.h
[...]
+#define BLKDBG_EVENT(child, evt) \
+ do { \
+ if (child) { \
+ bdrv_debug_event(child->bs, evt); \
+ } \
+ } while (0)
This is defined twice, once here, and...
This is unnecessary, as bdrv_debug_event is in block-io.c
Will remove that.
diff --git a/include/block/block-io.h b/include/block/block-io.h
new file mode 100644
index 0000000000..9af4609ccb
--- /dev/null
+++ b/include/block/block-io.h
[...]
+#define BLKDBG_EVENT(child, evt) \
+ do { \
+ if (child) { \
+ bdrv_debug_event(child->bs, evt); \
+ } \
+ } while (0)
...once here.
[...]
+/**
+ * bdrv_drained_begin:
+ *
+ * Begin a quiesced section for exclusive access to the BDS, by
disabling
+ * external request sources including NBD server and device model.
Note that
+ * this doesn't block timers or coroutines from submitting more
requests, which
+ * means block_job_pause is still necessary.
Where does this sentence come from? I can’t see it in master or in the
lines removed from block.h:
This is another mistake, I copied the old header. This sentence was
removed by this patch (sent by me) and then merged in master:
https://patchew.org/QEMU/20210903113800.59970-1-eespo...@redhat.com/
Will fix this and double check all headers so that the comments are
updated (but there shouldn't be any other mistakes).
Thank you,
Emanuele
