From f210912d1aa91e7c16f9dab7b2a43f1134db23da Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Wed, 31 Aug 2022 16:58:23 +0000 Subject: [PATCH] xen-blkfront: Advertise feature-persistent as user requested MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 9f5e0fe5d05f7e8de7f39b2b10089834eb0ff787 upstream. The advertisement of the persistent grants feature (writing 'feature-persistent' to xenbus) should mean not the decision for using the feature but only the availability of the feature. However, commit 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants") made a field of blkfront, which was a place for saving only the negotiation result, to be used for yet another purpose: caching of the 'feature_persistent' parameter value. As a result, the advertisement, which should follow only the parameter value, becomes inconsistent. This commit fixes the misuse of the semantic by making blkfront saves the parameter value in a separate place and advertises the support based on only the saved value. Fixes: 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants") Cc: # 5.10.x Suggested-by: Juergen Gross Signed-off-by: SeongJae Park Tested-by: Marek Marczykowski-Górecki Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20220831165824.94815-3-sj@kernel.org Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/block/xen-blkfront.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 03e079a6f072..9d5460f6e0ff 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -211,6 +211,9 @@ struct blkfront_info unsigned int feature_fua:1; unsigned int feature_discard:1; unsigned int feature_secdiscard:1; + /* Connect-time cached feature_persistent parameter */ + unsigned int feature_persistent_parm:1; + /* Persistent grants feature negotiation result */ unsigned int feature_persistent:1; unsigned int bounce:1; unsigned int discard_granularity; @@ -1941,7 +1944,7 @@ again: goto abort_transaction; } err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", - info->feature_persistent); + info->feature_persistent_parm); if (err) dev_warn(&dev->dev, "writing persistent grants feature to xenbus"); @@ -2391,7 +2394,8 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0)) blkfront_setup_discard(info); - if (feature_persistent) + info->feature_persistent_parm = feature_persistent; + if (info->feature_persistent_parm) info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend, "feature-persistent", 0);