[net-next,v5,1/2] netconsole: Create a allocation helper
Commit Message
De-duplicate the initialization and allocation code for struct
netconsole_target.
The same allocation and initialization code is duplicated in two
different places in the netconsole subsystem, when the netconsole target
is initialized by command line parameters (alloc_param_target()), and
dynamically by sysfs (make_netconsole_target()).
Create a helper function, and call it from the two different functions.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
drivers/net/netconsole.c | 42 +++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 20 deletions(-)
Comments
On Thu, Aug 10, 2023 at 02:54:50AM -0700, Breno Leitao wrote:
> De-duplicate the initialization and allocation code for struct
> netconsole_target.
>
> The same allocation and initialization code is duplicated in two
> different places in the netconsole subsystem, when the netconsole target
> is initialized by command line parameters (alloc_param_target()), and
> dynamically by sysfs (make_netconsole_target()).
>
> Create a helper function, and call it from the two different functions.
>
> Suggested-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> drivers/net/netconsole.c | 42 +++++++++++++++++++++-------------------
> 1 file changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index 87f18aedd3bd..f93b98d64a3c 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -167,19 +167,16 @@ static void netconsole_target_put(struct netconsole_target *nt)
>
> #endif /* CONFIG_NETCONSOLE_DYNAMIC */
>
> -/* Allocate new target (from boot/module param) and setup netpoll for it */
> -static struct netconsole_target *alloc_param_target(char *target_config)
> +/* Allocate and initialize with defaults.
> + * Note that these targets get their config_item fields zeroed-out.
> + */
> +static struct netconsole_target *alloc_and_init(void)
> {
> - int err = -ENOMEM;
> struct netconsole_target *nt;
>
> - /*
> - * Allocate and initialize with defaults.
> - * Note that these targets get their config_item fields zeroed-out.
> - */
> nt = kzalloc(sizeof(*nt), GFP_KERNEL);
> if (!nt)
> - goto fail;
> + return nt;
>
> nt->np.name = "netconsole";
> strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
> @@ -187,6 +184,21 @@ static struct netconsole_target *alloc_param_target(char *target_config)
> nt->np.remote_port = 6666;
> eth_broadcast_addr(nt->np.remote_mac);
>
> + return nt;
> +}
> +
> +/* Allocate new target (from boot/module param) and setup netpoll for it */
> +static struct netconsole_target *alloc_param_target(char *target_config)
> +{
> + struct netconsole_target *nt;
> + int err;
Hi Breno,
This function returns err.
However, clang-16 W=1 and Smatch warn that there is a case
where this may occur without err having being initialised.
> +
> + nt = alloc_and_init();
> + if (!nt) {
> + err = -ENOMEM;
> + goto fail;
> + }
> +
> if (*target_config == '+') {
> nt->extended = true;
> target_config++;
...
Hello Simon,
On Thu, Aug 10, 2023 at 10:17:18PM +0200, Simon Horman wrote:
> On Thu, Aug 10, 2023 at 02:54:50AM -0700, Breno Leitao wrote:
> > De-duplicate the initialization and allocation code for struct
> > netconsole_target.
> >
> > The same allocation and initialization code is duplicated in two
> > different places in the netconsole subsystem, when the netconsole target
> > is initialized by command line parameters (alloc_param_target()), and
> > dynamically by sysfs (make_netconsole_target()).
> >
> > Create a helper function, and call it from the two different functions.
> >
> > Suggested-by: Eric Dumazet <edumazet@google.com>
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> > drivers/net/netconsole.c | 42 +++++++++++++++++++++-------------------
> > 1 file changed, 22 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> > index 87f18aedd3bd..f93b98d64a3c 100644
> > --- a/drivers/net/netconsole.c
> > +++ b/drivers/net/netconsole.c
> > @@ -167,19 +167,16 @@ static void netconsole_target_put(struct netconsole_target *nt)
> >
> > #endif /* CONFIG_NETCONSOLE_DYNAMIC */
> >
> > -/* Allocate new target (from boot/module param) and setup netpoll for it */
> > -static struct netconsole_target *alloc_param_target(char *target_config)
> > +/* Allocate and initialize with defaults.
> > + * Note that these targets get their config_item fields zeroed-out.
> > + */
> > +static struct netconsole_target *alloc_and_init(void)
> > {
> > - int err = -ENOMEM;
> > struct netconsole_target *nt;
> >
> > - /*
> > - * Allocate and initialize with defaults.
> > - * Note that these targets get their config_item fields zeroed-out.
> > - */
> > nt = kzalloc(sizeof(*nt), GFP_KERNEL);
> > if (!nt)
> > - goto fail;
> > + return nt;
> >
> > nt->np.name = "netconsole";
> > strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
> > @@ -187,6 +184,21 @@ static struct netconsole_target *alloc_param_target(char *target_config)
> > nt->np.remote_port = 6666;
> > eth_broadcast_addr(nt->np.remote_mac);
> >
> > + return nt;
> > +}
> > +
> > +/* Allocate new target (from boot/module param) and setup netpoll for it */
> > +static struct netconsole_target *alloc_param_target(char *target_config)
> > +{
> > + struct netconsole_target *nt;
> > + int err;
>
> Hi Breno,
>
> This function returns err.
> However, clang-16 W=1 and Smatch warn that there is a case
> where this may occur without err having being initialised.
That can really happen, if we get into this function:
if (*target_config == 'r') {
if (!nt->extended) {
pr_err("Netconsole configuration error. Release feature requires extended log message");
goto fail;
fail:
return ERR_PTR(err);
Let me update it.
@@ -167,19 +167,16 @@ static void netconsole_target_put(struct netconsole_target *nt)
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
-/* Allocate new target (from boot/module param) and setup netpoll for it */
-static struct netconsole_target *alloc_param_target(char *target_config)
+/* Allocate and initialize with defaults.
+ * Note that these targets get their config_item fields zeroed-out.
+ */
+static struct netconsole_target *alloc_and_init(void)
{
- int err = -ENOMEM;
struct netconsole_target *nt;
- /*
- * Allocate and initialize with defaults.
- * Note that these targets get their config_item fields zeroed-out.
- */
nt = kzalloc(sizeof(*nt), GFP_KERNEL);
if (!nt)
- goto fail;
+ return nt;
nt->np.name = "netconsole";
strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
@@ -187,6 +184,21 @@ static struct netconsole_target *alloc_param_target(char *target_config)
nt->np.remote_port = 6666;
eth_broadcast_addr(nt->np.remote_mac);
+ return nt;
+}
+
+/* Allocate new target (from boot/module param) and setup netpoll for it */
+static struct netconsole_target *alloc_param_target(char *target_config)
+{
+ struct netconsole_target *nt;
+ int err;
+
+ nt = alloc_and_init();
+ if (!nt) {
+ err = -ENOMEM;
+ goto fail;
+ }
+
if (*target_config == '+') {
nt->extended = true;
target_config++;
@@ -664,23 +676,13 @@ static const struct config_item_type netconsole_target_type = {
static struct config_item *make_netconsole_target(struct config_group *group,
const char *name)
{
- unsigned long flags;
struct netconsole_target *nt;
+ unsigned long flags;
- /*
- * Allocate and initialize with defaults.
- * Target is disabled at creation (!enabled).
- */
- nt = kzalloc(sizeof(*nt), GFP_KERNEL);
+ nt = alloc_and_init();
if (!nt)
return ERR_PTR(-ENOMEM);
- nt->np.name = "netconsole";
- strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
- nt->np.local_port = 6665;
- nt->np.remote_port = 6666;
- eth_broadcast_addr(nt->np.remote_mac);
-
/* Initialize the config_item member */
config_item_init_type_name(&nt->item, name, &netconsole_target_type);