From: Markus Armbruster <armbru@redhat.com>
To: Eric Blake <eblake@redhat.com>
Cc: kwolf@redhat.com, vsementsov@virtuozzo.com,
qemu-block@nongnu.org, rjones@redhat.com, qemu-devel@nongnu.org,
Max Reitz <mreitz@redhat.com>,
stefanha@redhat.com
Subject: Re: [PATCH v5 03/12] nbd: Utilize QAPI_CLONE for type conversion
Date: Mon, 26 Oct 2020 15:41:28 +0100 [thread overview]
Message-ID: <87r1pl3v8n.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <20201023183652.478921-4-eblake@redhat.com> (Eric Blake's message of "Fri, 23 Oct 2020 13:36:43 -0500")
Eric Blake <eblake@redhat.com> writes:
> Rather than open-coding the translation from the deprecated
> NbdServerAddOptions type to the preferred BlockExportOptionsNbd, it's
> better to utilize QAPI_CLONE_MEMBERS. This solves a couple of issues:
> first, if we do any more refactoring of the base type (which an
> upcoming patch plans to do), we don't have to revisit the open-coding.
> Second, our assignment to arg->name is fishy: the generated QAPI code
> currently does not visit it if arg->has_name is false, but if it DID
> visit it, we would have introduced a double-free situation when arg is
> finally freed.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
> blockdev-nbd.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/blockdev-nbd.c b/blockdev-nbd.c
> index 8174023e5c47..cee9134b12eb 100644
> --- a/blockdev-nbd.c
> +++ b/blockdev-nbd.c
> @@ -14,6 +14,8 @@
> #include "sysemu/block-backend.h"
> #include "hw/block/block.h"
> #include "qapi/error.h"
> +#include "qapi/clone-visitor.h"
> +#include "qapi/qapi-visit-block-export.h"
> #include "qapi/qapi-commands-block-export.h"
> #include "block/nbd.h"
> #include "io/channel-socket.h"
> @@ -195,7 +197,8 @@ void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
> * the device name as a default here for compatibility.
> */
> if (!arg->has_name) {
> - arg->name = arg->device;
> + arg->has_name = true;
> + arg->name = g_strdup(arg->device);
> }
This is the fix you mentioned in the commit message.
>
> export_opts = g_new(BlockExportOptions, 1);
> @@ -205,15 +208,9 @@ void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
*export_opts = (BlockExportOptions) {
.type = BLOCK_EXPORT_TYPE_NBD,
.id = g_strdup(arg->name),
> .node_name = g_strdup(bdrv_get_node_name(bs)),
> .has_writable = arg->has_writable,
> .writable = arg->writable,
Explicit initialization of all the common members, except for
@writethrough. @writethrough is optional, so not mentioning it makes it
absent. I don't mind.
> - .u.nbd = {
> - .has_name = true,
> - .name = g_strdup(arg->name),
> - .has_description = arg->has_description,
> - .description = g_strdup(arg->description),
> - .has_bitmap = arg->has_bitmap,
> - .bitmap = g_strdup(arg->bitmap),
Explicit initialization of all the variant members: copy of @arg.
> - },
> };
> + QAPI_CLONE_MEMBERS(BlockExportOptionsNbd, &export_opts->u.nbd,
> + qapi_NbdServerAddOptions_base(arg));
Another (and better) way to copy.
>
> /*
> * nbd-server-add doesn't complain when a read-only device should be
Reviewed-by: Markus Armbruster <armbru@redhat.com>
next prev parent reply other threads:[~2020-10-26 14:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 18:36 [PATCH v5 00/12] Exposing backing-chain allocation over NBD Eric Blake
2020-10-23 18:36 ` [PATCH v5 01/12] qapi: Move GenericList to qapi/util.h Eric Blake
2020-10-24 9:06 ` Vladimir Sementsov-Ogievskiy
2020-10-26 14:18 ` Markus Armbruster
2020-10-26 14:22 ` Eric Blake
2020-10-23 18:36 ` [PATCH v5 02/12] qapi: Make QAPI_LIST_ADD() public Eric Blake
2020-10-24 9:10 ` Vladimir Sementsov-Ogievskiy
2020-10-26 14:25 ` Markus Armbruster
2020-10-26 14:37 ` Eric Blake
2020-10-26 14:38 ` Eric Blake
2020-10-23 18:36 ` [PATCH v5 03/12] nbd: Utilize QAPI_CLONE for type conversion Eric Blake
2020-10-24 9:17 ` Vladimir Sementsov-Ogievskiy
2020-10-26 14:41 ` Markus Armbruster [this message]
2020-10-23 18:36 ` [PATCH v5 04/12] nbd: Add new qemu:allocation-depth metadata context Eric Blake
2020-10-23 18:36 ` [PATCH v5 05/12] nbd: Add 'qemu-nbd -A' to expose allocation depth Eric Blake
2020-10-23 18:36 ` [PATCH v5 06/12] nbd: Update qapi to support exporting multiple bitmaps Eric Blake
2020-10-26 10:50 ` Peter Krempa
2020-10-26 13:06 ` Eric Blake
2020-10-23 18:36 ` [PATCH v5 07/12] nbd: Simplify qemu bitmap context name Eric Blake
2020-10-23 18:36 ` [PATCH v5 08/12] nbd: Refactor counting of metadata contexts Eric Blake
2020-10-23 18:36 ` [PATCH v5 09/12] nbd: Allow export of multiple bitmaps for one device Eric Blake
2020-10-23 18:36 ` [PATCH v5 10/12] block: Return depth level during bdrv_is_allocated_above Eric Blake
2020-10-24 9:49 ` Vladimir Sementsov-Ogievskiy
2020-10-26 12:26 ` Vladimir Sementsov-Ogievskiy
2020-10-23 18:36 ` [PATCH v5 11/12] nbd: Expose actual depth in qemu:allocation-depth Eric Blake
2020-10-24 9:59 ` Vladimir Sementsov-Ogievskiy
2020-10-26 12:31 ` Eric Blake
2020-10-23 18:36 ` [PATCH v5 12/12] qapi: Use QAPI_LIST_ADD() where possible Eric Blake
2020-10-23 20:23 ` Eric Blake
2020-10-23 18:44 ` [PATCH v5 00/12] Exposing backing-chain allocation over NBD Eric Blake
2020-10-26 14:54 ` Markus Armbruster
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