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Message-ID: <Y4XADTlOkROnuaWL@nanopsycho>
Date: Tue, 29 Nov 2022 09:17:17 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Jacob Keller <jacob.e.keller@...el.com>
Cc: netdev@...r.kernel.org, Jiri Pirko <jiri@...dia.com>,
Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH net-next v3 6/9] devlink: support directly reading from
region memory
Mon, Nov 28, 2022 at 09:36:44PM CET, jacob.e.keller@...el.com wrote:
>To read from a region, user space must currently request a new snapshot of
>the region and then read from that snapshot. This can sometimes be overkill
>if user space only reads a tiny portion. They first create the snapshot,
>then request a read, then destroy the snapshot.
>
>For regions which have a single underlying "contents", it makes sense to
>allow supporting direct reading of the region data.
>
>Extend the DEVLINK_CMD_REGION_READ to allow direct reading from a region if
>requested via the new DEVLINK_ATTR_REGION_DIRECT. If this attribute is set,
>then perform a direct read instead of using a snapshot. Direct read is
>mutually exclusive with DEVLINK_ATTR_REGION_SNAPSHOT_ID, and care is taken
>to ensure that we reject commands which provide incorrect attributes.
>
>Regions must enable support for direct read by implementing the .read()
>callback function. If a region does not support such direct reads, a
>suitable extended error message is reported.
>
>Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Reviewed-by: Jiri Pirko <jiri@...dia.com>
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