| Message ID | 1495198042-124203-6-git-send-email-anton.nefedov@virtuozzo.com |
|---|---|
| State | New |
| Headers | show |
On Fri, May 19, 2017 at 4:49 PM Anton Nefedov <anton.nefedov@virtuozzo.com> wrote: > qemu_chr_fe_get_driver() is unsafe, frontends with hotswap support > should not access CharDriver ptr directly as CharDriver might change. > Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com> > Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > I would move this patch up in the series, otherwise looks good > --- > chardev/char.c | 7 +++++++ > include/sysemu/char.h | 10 ++++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/chardev/char.c b/chardev/char.c > index 0483f19..36d6f36 100644 > --- a/chardev/char.c > +++ b/chardev/char.c > @@ -484,9 +484,16 @@ static Notifier muxes_realize_notify = { > > Chardev *qemu_chr_fe_get_driver(CharBackend *be) > { > + /* this is unsafe for the users that support chardev hotswap */ > + assert(be->chr_be_change == NULL); > return be->chr; > } > > +bool qemu_chr_fe_backend_connected(CharBackend *be) > +{ > + return !!be->chr; > +} > + > static bool fe_connect(CharBackend *b, Chardev *s, Error **errp) > { > int tag = 0; > diff --git a/include/sysemu/char.h b/include/sysemu/char.h > index 92ae57e..fa21535 100644 > --- a/include/sysemu/char.h > +++ b/include/sysemu/char.h > @@ -404,10 +404,20 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, > Error **errp); > * > * Returns the driver associated with a CharBackend or NULL if no > * associated Chardev. > + * Note: avoid this function as the driver should never be accessed > directly, > + * especially by the frontends that support chardevice hotswap. > + * Consider qemu_chr_fe_backend_connected() to check for driver > existence > */ > Chardev *qemu_chr_fe_get_driver(CharBackend *be); > > /** > + * @qemu_chr_fe_backend_connected: > + * > + * Returns true if there is a chardevice associated with @be. > + */ > +bool qemu_chr_fe_backend_connected(CharBackend *be); > + > +/** > * @qemu_chr_fe_deinit: > * > * Dissociate the CharBackend from the Chardev. > -- > 2.7.4 > > > -- Marc-André Lureau
diff --git a/chardev/char.c b/chardev/char.c index 0483f19..36d6f36 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -484,9 +484,16 @@ static Notifier muxes_realize_notify = { Chardev *qemu_chr_fe_get_driver(CharBackend *be) { + /* this is unsafe for the users that support chardev hotswap */ + assert(be->chr_be_change == NULL); return be->chr; } +bool qemu_chr_fe_backend_connected(CharBackend *be) +{ + return !!be->chr; +} + static bool fe_connect(CharBackend *b, Chardev *s, Error **errp) { int tag = 0; diff --git a/include/sysemu/char.h b/include/sysemu/char.h index 92ae57e..fa21535 100644 --- a/include/sysemu/char.h +++ b/include/sysemu/char.h @@ -404,10 +404,20 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp); * * Returns the driver associated with a CharBackend or NULL if no * associated Chardev. + * Note: avoid this function as the driver should never be accessed directly, + * especially by the frontends that support chardevice hotswap. + * Consider qemu_chr_fe_backend_connected() to check for driver existence */ Chardev *qemu_chr_fe_get_driver(CharBackend *be); /** + * @qemu_chr_fe_backend_connected: + * + * Returns true if there is a chardevice associated with @be. + */ +bool qemu_chr_fe_backend_connected(CharBackend *be); + +/** * @qemu_chr_fe_deinit: * * Dissociate the CharBackend from the Chardev.