diff mbox series

[bpf,1/2] bpftool: support queues and stacks in update command

Message ID 20190103183306.232540-1-sdf@google.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series [bpf,1/2] bpftool: support queues and stacks in update command | expand

Commit Message

Stanislav Fomichev Jan. 3, 2019, 6:33 p.m. UTC
Bpftool expects both key and value for 'update' operations. For some
map types, key should not be specified. Support updating those map types.

Before:
bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3
Error: did not find key

After:
bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/bpf/bpftool/Documentation/bpftool-map.rst |  4 ++--
 tools/bpf/bpftool/map.c                         | 15 +++++++++++----
 2 files changed, 13 insertions(+), 6 deletions(-)

Comments

Jakub Kicinski Jan. 3, 2019, 7:43 p.m. UTC | #1
On Thu,  3 Jan 2019 10:33:05 -0800, Stanislav Fomichev wrote:
> Bpftool expects both key and value for 'update' operations. For some
> map types, key should not be specified. Support updating those map types.
> 
> Before:
> bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
> bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3
> Error: did not find key
> 
> After:
> bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
> bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3
> 
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

I guess it doesn't hurt to fix update/lookup, but I'd prefer to see new
separate subcommands to be honest :(

bpftool map push/pop/peek

Could you add those as well?  I think most users will be more familiar
with the helpers than the fact that the syscall reuses the old commands.

> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index 2037e3dc864b..30b92715248d 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -781,11 +781,11 @@ static int do_dump(int argc, char **argv)
>  
>  static int do_update(int argc, char **argv)
>  {
> +	void *key = NULL, *value = NULL;

nit: it seems tiny bit more readable to init these in the place you'd
     otherwise set key to malloc (in an else clause)

>  	struct bpf_map_info info = {};
>  	__u32 len = sizeof(info);
>  	__u32 *value_fd = NULL;
>  	__u32 flags = BPF_ANY;
> -	void *key, *value;
>  	int fd, err;
>  
>  	if (argc < 2)
> @@ -795,9 +795,16 @@ static int do_update(int argc, char **argv)
>  	if (fd < 0)
>  		return -1;
>  
> -	key = malloc(info.key_size);
> +	if (info.key_size) {
> +		key = malloc(info.key_size);
> +		if (!key) {
> +			p_err("mem alloc failed");
> +			err = -1;
> +			goto exit_free;
> +		}
> +	}
>  	value = alloc_value(&info);

Would you mind taking care of the value as well?  So we are ready if
sets are ever added?

> -	if (!key || !value) {
> +	if (!value) {
>  		p_err("mem alloc failed");
>  		err = -1;
>  		goto exit_free;

I'd consider this -next material TBH, but not strongly.
Stanislav Fomichev Jan. 3, 2019, 8:52 p.m. UTC | #2
On Thu, Jan 3, 2019 at 11:43 AM Jakub Kicinski
<jakub.kicinski@netronome.com> wrote:
>
> On Thu,  3 Jan 2019 10:33:05 -0800, Stanislav Fomichev wrote:
> > Bpftool expects both key and value for 'update' operations. For some
> > map types, key should not be specified. Support updating those map types.
> >
> > Before:
> > bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
> > bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3
> > Error: did not find key
> >
> > After:
> > bpftool map create /sys/fs/bpf/q type queue value 4 entries 10 name q
> > bpftool map update pinned /sys/fs/bpf/q value 0 1 2 3
> >
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
>
> I guess it doesn't hurt to fix update/lookup, but I'd prefer to see new
> separate subcommands to be honest :(
>
> bpftool map push/pop/peek
>
> Could you add those as well?  I think most users will be more familiar
> with the helpers than the fact that the syscall reuses the old commands.
Sure, I thought about that, but decided to mirror syscall interface initially.
I can do both: support update/lookup and add new commands.

>
> > diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> > index 2037e3dc864b..30b92715248d 100644
> > --- a/tools/bpf/bpftool/map.c
> > +++ b/tools/bpf/bpftool/map.c
> > @@ -781,11 +781,11 @@ static int do_dump(int argc, char **argv)
> >
> >  static int do_update(int argc, char **argv)
> >  {
> > +     void *key = NULL, *value = NULL;
>
> nit: it seems tiny bit more readable to init these in the place you'd
>      otherwise set key to malloc (in an else clause)
Ack, will do.

>
> >       struct bpf_map_info info = {};
> >       __u32 len = sizeof(info);
> >       __u32 *value_fd = NULL;
> >       __u32 flags = BPF_ANY;
> > -     void *key, *value;
> >       int fd, err;
> >
> >       if (argc < 2)
> > @@ -795,9 +795,16 @@ static int do_update(int argc, char **argv)
> >       if (fd < 0)
> >               return -1;
> >
> > -     key = malloc(info.key_size);
> > +     if (info.key_size) {
> > +             key = malloc(info.key_size);
> > +             if (!key) {
> > +                     p_err("mem alloc failed");
> > +                     err = -1;
> > +                     goto exit_free;
> > +             }
> > +     }
> >       value = alloc_value(&info);
>
> Would you mind taking care of the value as well?  So we are ready if
> sets are ever added?
Sure, makes sense.

>
> > -     if (!key || !value) {
> > +     if (!value) {
> >               p_err("mem alloc failed");
> >               err = -1;
> >               goto exit_free;
>
> I'd consider this -next material TBH, but not strongly.
My initial thought that these two can go into bpf as 'fixes' because
they technically don't add any new features.
But I'm fine with -next as well, I'll prepare a v2 for bpf-next with
those two changes plus push/pop/peek.

Thank you for a review!
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index 64b001b4f777..81842fdf483d 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
@@ -25,7 +25,7 @@  MAP COMMANDS
 |	**bpftool** **map create**     *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* \
 |		**entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*]
 |	**bpftool** **map dump**       *MAP*
-|	**bpftool** **map update**     *MAP*  **key** *DATA*   **value** *VALUE* [*UPDATE_FLAGS*]
+|	**bpftool** **map update**     *MAP* [**key** *DATA*]  **value** *VALUE* [*UPDATE_FLAGS*]
 |	**bpftool** **map lookup**     *MAP*  **key** *DATA*
 |	**bpftool** **map getnext**    *MAP* [**key** *DATA*]
 |	**bpftool** **map delete**     *MAP*  **key** *DATA*
@@ -62,7 +62,7 @@  DESCRIPTION
 	**bpftool map dump**    *MAP*
 		  Dump all entries in a given *MAP*.
 
-	**bpftool map update**  *MAP*  **key** *DATA*   **value** *VALUE* [*UPDATE_FLAGS*]
+	**bpftool map update**  *MAP* [**key** *DATA*]  **value** *VALUE* [*UPDATE_FLAGS*]
 		  Update map entry for a given *KEY*.
 
 		  *UPDATE_FLAGS* can be one of: **any** update existing entry
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 2037e3dc864b..30b92715248d 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -781,11 +781,11 @@  static int do_dump(int argc, char **argv)
 
 static int do_update(int argc, char **argv)
 {
+	void *key = NULL, *value = NULL;
 	struct bpf_map_info info = {};
 	__u32 len = sizeof(info);
 	__u32 *value_fd = NULL;
 	__u32 flags = BPF_ANY;
-	void *key, *value;
 	int fd, err;
 
 	if (argc < 2)
@@ -795,9 +795,16 @@  static int do_update(int argc, char **argv)
 	if (fd < 0)
 		return -1;
 
-	key = malloc(info.key_size);
+	if (info.key_size) {
+		key = malloc(info.key_size);
+		if (!key) {
+			p_err("mem alloc failed");
+			err = -1;
+			goto exit_free;
+		}
+	}
 	value = alloc_value(&info);
-	if (!key || !value) {
+	if (!value) {
 		p_err("mem alloc failed");
 		err = -1;
 		goto exit_free;
@@ -1135,7 +1142,7 @@  static int do_help(int argc, char **argv)
 		"                              entries MAX_ENTRIES name NAME [flags FLAGS] \\\n"
 		"                              [dev NAME]\n"
 		"       %s %s dump       MAP\n"
-		"       %s %s update     MAP  key DATA value VALUE [UPDATE_FLAGS]\n"
+		"       %s %s update     MAP [key DATA] value VALUE [UPDATE_FLAGS]\n"
 		"       %s %s lookup     MAP  key DATA\n"
 		"       %s %s getnext    MAP [key DATA]\n"
 		"       %s %s delete     MAP  key DATA\n"