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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, stefanha@redhat.com, hreitz@redhat.com,
	eblake@redhat.com, qemu-devel@nongnu.org
Subject: [PATCH 02/12] block: Clarify locking rules for bdrv_open(_inherit)()
Date: Thu, 25 May 2023 14:47:03 +0200	[thread overview]
Message-ID: <20230525124713.401149-3-kwolf@redhat.com> (raw)
In-Reply-To: <20230525124713.401149-1-kwolf@redhat.com>

These functions specify that the caller must hold the "@filename
AioContext lock". This doesn't make sense, file names don't have an
AioContext. New BlockDriverStates always start in the main AioContext,
so this is what we really need here.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/block.c b/block.c
index a2f8d5a0c0..6ac47112fe 100644
--- a/block.c
+++ b/block.c
@@ -3810,9 +3810,7 @@ out:
  * should be opened. If specified, neither options nor a filename may be given,
  * nor can an existing BDS be reused (that is, *pbs has to be NULL).
  *
- * The caller must always hold @filename AioContext lock, because this
- * function eventually calls bdrv_refresh_total_sectors() which polls
- * when called from non-coroutine context.
+ * The caller must always hold the main AioContext lock.
  */
 static BlockDriverState * no_coroutine_fn
 bdrv_open_inherit(const char *filename, const char *reference, QDict *options,
@@ -4100,11 +4098,7 @@ close_and_fail:
     return NULL;
 }
 
-/*
- * The caller must always hold @filename AioContext lock, because this
- * function eventually calls bdrv_refresh_total_sectors() which polls
- * when called from non-coroutine context.
- */
+/* The caller must always hold the main AioContext lock. */
 BlockDriverState *bdrv_open(const char *filename, const char *reference,
                             QDict *options, int flags, Error **errp)
 {
-- 
2.40.1



  parent reply	other threads:[~2023-05-25 12:48 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-25 12:47 [PATCH 00/12] block: Fix blockdev-create with iothreads Kevin Wolf
2023-05-25 12:47 ` [PATCH 01/12] block-coroutine-wrapper: Take AioContext lock in no_co_wrappers Kevin Wolf
2023-05-25 18:15   ` Stefan Hajnoczi
2023-05-25 12:47 ` Kevin Wolf [this message]
2023-05-25 18:16   ` [PATCH 02/12] block: Clarify locking rules for bdrv_open(_inherit)() Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 03/12] block: Take main AioContext lock when calling bdrv_open() Kevin Wolf
2023-05-25 18:20   ` Stefan Hajnoczi
2023-05-26  8:27     ` Kevin Wolf
2023-05-25 12:47 ` [PATCH 04/12] block-backend: Fix blk_new_open() for iothreads Kevin Wolf
2023-05-25 18:37   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 05/12] mirror: Hold main AioContext lock for calling bdrv_open_backing_file() Kevin Wolf
2023-05-25 18:40   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 06/12] qcow2: Fix open with 'file' in iothread Kevin Wolf
2023-05-25 18:51   ` Stefan Hajnoczi
2023-05-26  8:40     ` Kevin Wolf
2023-05-26  9:04       ` Kevin Wolf
2023-05-25 12:47 ` [PATCH 07/12] raw-format: " Kevin Wolf
2023-05-25 18:52   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 08/12] copy-before-write: Fix open with child " Kevin Wolf
2023-05-25 18:55   ` Stefan Hajnoczi
2023-05-26 14:30   ` Eric Blake
2023-05-25 12:47 ` [PATCH 09/12] block: Take AioContext lock in bdrv_open_driver() Kevin Wolf
2023-05-25 18:56   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 10/12] block: Fix AioContext locking in bdrv_insert_node() Kevin Wolf
2023-05-25 18:58   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 11/12] iotests: Make verify_virtio_scsi_pci_or_ccw() public Kevin Wolf
2023-05-25 18:59   ` Stefan Hajnoczi
2023-05-25 12:47 ` [PATCH 12/12] iotests: Test blockdev-create in iothread Kevin Wolf
2023-05-25 19:01   ` Stefan Hajnoczi

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