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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     =?UTF-8?q?Jan=20H=C3=B6ppner?= <hoeppner@linux.ibm.com>,
        Stefan Haberland <sth@linux.ibm.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
        linux-s390@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 040/130] s390/dasd: Fix operational path inconsistency
Date:   Tue, 22 Dec 2020 21:16:43 -0500
Message-Id: <20201223021813.2791612-40-sashal@kernel.org>
In-Reply-To: <20201223021813.2791612-1-sashal@kernel.org>
References: <20201223021813.2791612-1-sashal@kernel.org>
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From: Jan Höppner <hoeppner@linux.ibm.com>

[ Upstream commit 9e34c8ba91697cb7441805c36d92ab3e695df6e0 ]

During online processing and setting up a DASD device, the configuration
data for operational paths is read and validated two times
(dasd_eckd_read_conf()). The first time to provide information that are
necessary for the LCU setup. A second time after the LCU setup as a
device might report different configuration data then.

When the configuration setup for each operational path is being
validated, an initial call to dasd_eckd_clear_conf_data() is issued.
This call wipes all previously available configuration data and path
information for each path.
However, the operational path mask is not updated during this process.

As a result, the stored operational path mask might no longer correspond
to the operational paths mask reported by the CIO layer, as several
paths might be gone between the two dasd_eckd_read_conf() calls.

This inconsistency leads to more severe issues in later path handling
changes. Fix this by removing the channel paths from the operational
path mask during the dasd_eckd_clear_conf_data() call.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/block/dasd_eckd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index ad44d22e88591..b2964c204fefb 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1013,6 +1013,7 @@ static void dasd_eckd_clear_conf_data(struct dasd_device *device)
 		device->path[i].cssid = 0;
 		device->path[i].ssid = 0;
 		device->path[i].chpid = 0;
+		dasd_path_notoper(device, i);
 	}
 }
 
-- 
2.27.0