The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 658a337a606f48b7ebe451591f7681d383fa115e Mon Sep 17 00:00:00 2001
From: Stefan Haberland sth@linux.ibm.com Date: Thu, 17 Dec 2020 16:59:04 +0100 Subject: [PATCH] s390/dasd: fix hanging device offline processing
For an LCU update a read unit address configuration IO is required. This is started using sleep_on(), which has early exit paths in case the device is not usable for IO. For example when it is in offline processing.
In those cases the LCU update should fail and not be retried. Therefore lcu_update_work checks if EOPNOTSUPP is returned or not.
Commit 41995342b40c ("s390/dasd: fix endless loop after read unit address configuration") accidentally removed the EOPNOTSUPP return code from read_unit_address_configuration(), which in turn might lead to an endless loop of the LCU update in offline processing.
Fix by returning EOPNOTSUPP again if the device is not able to perform the request.
Fixes: 41995342b40c ("s390/dasd: fix endless loop after read unit address configuration") Cc: stable@vger.kernel.org #5.3 Signed-off-by: Stefan Haberland sth@linux.ibm.com Reviewed-by: Jan Hoeppner hoeppner@linux.ibm.com Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c index 99f86612f775..31e8b5d48e86 100644 --- a/drivers/s390/block/dasd_alias.c +++ b/drivers/s390/block/dasd_alias.c @@ -462,11 +462,19 @@ static int read_unit_address_configuration(struct dasd_device *device, spin_unlock_irqrestore(&lcu->lock, flags);
rc = dasd_sleep_on(cqr); - if (rc && !suborder_not_supported(cqr)) { + if (!rc) + goto out; + + if (suborder_not_supported(cqr)) { + /* suborder not supported or device unusable for IO */ + rc = -EOPNOTSUPP; + } else { + /* IO failed but should be retried */ spin_lock_irqsave(&lcu->lock, flags); lcu->flags |= NEED_UAC_UPDATE; spin_unlock_irqrestore(&lcu->lock, flags); } +out: dasd_sfree_request(cqr, cqr->memdev); return rc; }