From: Simon Horman <horms@kernel.org>
To: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Jiri Pirko <jiri@resnulli.us>,
netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Shannon Nelson <shannon.nelson@amd.com>,
Michael Chan <michael.chan@broadcom.com>,
Cai Huoqing <cai.huoqing@linux.dev>,
George Cherian <george.cherian@marvell.com>,
Danielle Ratson <danieller@nvidia.com>,
Moshe Shemesh <moshe@nvidia.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Ariel Elior <aelior@marvell.com>,
Manish Chopra <manishc@marvell.com>,
Igor Russkikh <irusskikh@marvell.com>,
Coiby Xu <coiby.xu@gmail.com>,
Brett Creeley <brett.creeley@amd.com>,
Sunil Goutham <sgoutham@marvell.com>,
Linu Cherian <lcherian@marvell.com>,
Geetha sowjanya <gakula@marvell.com>,
Jerin Jacob <jerinj@marvell.com>, hariprasad <hkelam@marvell.com>,
Subbaraya Sundeep <sbhatta@marvell.com>,
Ido Schimmel <idosch@nvidia.com>, Petr Machata <petrm@nvidia.com>,
Eran Ben Elisha <eranbe@nvidia.com>,
Aya Levin <ayal@mellanox.com>, Leon Romanovsky <leon@kernel.org>,
linux-kernel@vger.kernel.org,
Benjamin Poirier <bpoirier@suse.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Jiri Pirko <jiri@nvidia.com>
Subject: Re: [PATCH net-next v3 01/11] devlink: retain error in struct devlink_fmsg
Date: Thu, 19 Oct 2023 15:00:37 +0200 [thread overview]
Message-ID: <20231019130037.GI2100445@kernel.org> (raw)
In-Reply-To: <20231018202647.44769-2-przemyslaw.kitszel@intel.com>
On Wed, Oct 18, 2023 at 10:26:37PM +0200, Przemek Kitszel wrote:
> Retain error value in struct devlink_fmsg, to relieve drivers from
> checking it after each call.
> Note that fmsg is an in-memory builder/buffer of formatted message,
> so it's not the case that half baked message was sent somewhere.
>
> We could find following scheme in multiple drivers:
> err = devlink_fmsg_obj_nest_start(fmsg);
> if (err)
> return err;
> err = devlink_fmsg_string_pair_put(fmsg, "src", src);
> if (err)
> return err;
> err = devlink_fmsg_something(fmsg, foo, bar);
> if (err)
> return err;
> // and so on...
> err = devlink_fmsg_obj_nest_end(fmsg);
>
> With retaining error API that translates to:
> devlink_fmsg_obj_nest_start(fmsg);
> devlink_fmsg_string_pair_put(fmsg, "src", src);
> devlink_fmsg_something(fmsg, foo, bar);
> // and so on...
> devlink_fmsg_obj_nest_end(fmsg);
>
> What means we check error just when is time to send.
>
> Possible error scenarios are developer error (API misuse) and memory
> exhaustion, both cases are good candidates to choose readability
> over fastest possible exit.
>
> Note that this patch keeps returning errors, to allow per-driver conversion
> to the new API, but those are not needed at this point already.
>
> This commit itself is an illustration of benefits for the dev-user,
> more of it will be in separate commits of the series.
>
> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
...
> @@ -1027,14 +934,12 @@ int devlink_fmsg_binary_pair_put(struct devlink_fmsg *fmsg, const char *name,
Hi Przemek,
The line before this hunk is:
err = devlink_fmsg_binary_put(fmsg, value + offset, data_size);
And, as of this patch, the implementation of
devlink_fmsg_binary_pair_nest_start() looks like this:
int devlink_fmsg_binary_put(struct devlink_fmsg *fmsg, const void *value,
u16 value_len)
{
if (!fmsg->putting_binary)
return -EINVAL;
return devlink_fmsg_put_value(fmsg, value, value_len, NLA_BINARY);
}
Which may return an error, if the if condition is met, without setting
fmsg->err.
> if (err)
> break;
> /* Exit from loop with a break (instead of
> - * return) to make sure putting_binary is turned off in
> - * devlink_fmsg_binary_pair_nest_end
> + * return) to make sure putting_binary is turned off
> */
> }
>
> - end_err = devlink_fmsg_binary_pair_nest_end(fmsg);
> - if (end_err)
> - err = end_err;
Prior to this patch, the value of err from the loop above was preserved,
unless devlink_fmsg_binary_pair_nest_end generated an error.
> + err = devlink_fmsg_binary_pair_nest_end(fmsg);
But now it looks like this is only the case if fmsg->err corresponds to err
when the loop was exited.
Or in other words, the err returned by devlink_fmsg_binary_put()
is not propagated to the caller if !fmsg->putting_binary.
If so, is this intentional?
> + fmsg->putting_binary = false;
>
> return err;
> }
> --
> 2.38.1
>
next prev parent reply other threads:[~2023-10-19 13:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-18 20:26 [PATCH net-next v3 00/11] devlink: retain error in struct devlink_fmsg Przemek Kitszel
2023-10-18 20:26 ` [PATCH net-next v3 01/11] " Przemek Kitszel
2023-10-19 13:00 ` Simon Horman [this message]
2023-10-19 21:49 ` Przemek Kitszel
2023-10-18 20:26 ` [PATCH net-next v3 02/11] netdevsim: devlink health: use retained error fmsg API Przemek Kitszel
2023-10-19 15:56 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 03/11] pds_core: " Przemek Kitszel
2023-10-19 15:56 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 04/11] bnxt_en: " Przemek Kitszel
2023-10-19 15:56 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 05/11] hinic: " Przemek Kitszel
2023-10-19 15:57 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 06/11] octeontx2-af: " Przemek Kitszel
2023-10-19 15:57 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 07/11] mlxsw: core: " Przemek Kitszel
2023-10-19 15:57 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 08/11] net/mlx5: " Przemek Kitszel
2023-10-19 15:58 ` Simon Horman
2023-10-24 9:50 ` Dan Carpenter
2023-10-24 13:43 ` Przemek Kitszel
2023-10-18 20:26 ` [PATCH net-next v3 09/11] qed: " Przemek Kitszel
2023-10-19 15:58 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 10/11] staging: qlge: " Przemek Kitszel
2023-10-19 15:58 ` Simon Horman
2023-10-18 20:26 ` [PATCH net-next v3 11/11] devlink: convert most of devlink_fmsg_*() to return void Przemek Kitszel
2023-10-19 13:44 ` [PATCH net-next v3 00/11] devlink: retain error in struct devlink_fmsg Jiri Pirko
2023-10-19 21:50 ` Przemek Kitszel
2023-10-20 9:36 ` Jiri Pirko
2023-10-20 10:40 ` patchwork-bot+netdevbpf
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