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Commit fe8f65b0 authored by SeongJae Park's avatar SeongJae Park Committed by Juergen Gross
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xen-blkfront: Cache feature_persistent value before advertisement



Xen blkfront advertises its support of the persistent grants feature
when it first setting up and when resuming in 'talk_to_blkback()'.
Then, blkback reads the advertised value when it connects with blkfront
and decides if it will use the persistent grants feature or not, and
advertises its decision to blkfront.  Blkfront reads the blkback's
decision and it also makes the decision for the use of the feature.

Commit 402c43ea ("xen-blkfront: Apply 'feature_persistent' parameter
when connect"), however, made the blkfront's read of the parameter for
disabling the advertisement, namely 'feature_persistent', to be done
when it negotiate, not when advertise.  Therefore blkfront advertises
without reading the parameter.  As the field for caching the parameter
value is zero-initialized, it always advertises as the feature is
disabled, so that the persistent grants feature becomes always disabled.

This commit fixes the issue by making the blkfront does parmeter caching
just before the advertisement.

Fixes: 402c43ea ("xen-blkfront: Apply 'feature_persistent' parameter when connect")
Cc: <stable@vger.kernel.org> # 5.10.x
Reported-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Tested-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220831165824.94815-4-sj@kernel.org


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 9f5e0fe5
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