The patch below does not apply to the 5.15-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.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 9daa5a8795865f9a3c93d8d1066785b07ded6073 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101905-depress-banjo-bc7e@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9daa5a8795865f9a3c93d8d1066785b07ded6073 Mon Sep 17 00:00:00 2001 From: Vineeth Vijayan vneethv@linux.ibm.com Date: Wed, 1 Oct 2025 15:38:17 +0200 Subject: [PATCH] s390/cio: Update purge function to unregister the unused subchannels
Starting with 'commit 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")', cio no longer unregisters subchannels when the attached device is invalid or unavailable.
As an unintended side-effect, the cio_ignore purge function no longer removes subchannels for devices on the cio_ignore list if no CCW device is attached. This situation occurs when a CCW device is non-operational or unavailable
To ensure the same outcome of the purge function as when the current cio_ignore list had been active during boot, update the purge function to remove I/O subchannels without working CCW devices if the associated device number is found on the cio_ignore list.
Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers") Suggested-by: Peter Oberparleiter oberpar@linux.ibm.com Reviewed-by: Peter Oberparleiter oberpar@linux.ibm.com Signed-off-by: Vineeth Vijayan vneethv@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index fb2c07cb4d3d..4b2dae6eb376 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -1316,23 +1316,34 @@ void ccw_device_schedule_recovery(void) spin_unlock_irqrestore(&recovery_lock, flags); }
-static int purge_fn(struct device *dev, void *data) +static int purge_fn(struct subchannel *sch, void *data) { - struct ccw_device *cdev = to_ccwdev(dev); - struct ccw_dev_id *id = &cdev->private->dev_id; - struct subchannel *sch = to_subchannel(cdev->dev.parent); + struct ccw_device *cdev;
- spin_lock_irq(cdev->ccwlock); - if (is_blacklisted(id->ssid, id->devno) && - (cdev->private->state == DEV_STATE_OFFLINE) && - (atomic_cmpxchg(&cdev->private->onoff, 0, 1) == 0)) { - CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid, - id->devno); + spin_lock_irq(&sch->lock); + if (sch->st != SUBCHANNEL_TYPE_IO || !sch->schib.pmcw.dnv) + goto unlock; + + if (!is_blacklisted(sch->schid.ssid, sch->schib.pmcw.dev)) + goto unlock; + + cdev = sch_get_cdev(sch); + if (cdev) { + if (cdev->private->state != DEV_STATE_OFFLINE) + goto unlock; + + if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0) + goto unlock; ccw_device_sched_todo(cdev, CDEV_TODO_UNREG); - css_sched_sch_todo(sch, SCH_TODO_UNREG); atomic_set(&cdev->private->onoff, 0); } - spin_unlock_irq(cdev->ccwlock); + + css_sched_sch_todo(sch, SCH_TODO_UNREG); + CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x%s\n", sch->schid.ssid, + sch->schib.pmcw.dev, cdev ? "" : " (no cdev)"); + +unlock: + spin_unlock_irq(&sch->lock); /* Abort loop in case of pending signal. */ if (signal_pending(current)) return -EINTR; @@ -1348,7 +1359,7 @@ static int purge_fn(struct device *dev, void *data) int ccw_purge_blacklisted(void) { CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n"); - bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn); + for_each_subchannel_staged(purge_fn, NULL, NULL); return 0; }