From df2382eb2374d4a90afe2a6f176e765028a4ee58 Mon Sep 17 00:00:00 2001 From: Vineeth Vijayan Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] s390/cio: Do not unregister the subchannel based on DNV BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit 8c58a229688ce3a097b3b1a2efe1b4f5508c2123 ] Starting with commit 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers"), CIO does not unregister subchannels when the attached device is invalid or unavailable. Instead, it allows subchannels to exist without a connected device. However, if the DNV value is 0, such as, when all the CHPIDs of a subchannel are configured in standby state, the subchannel is unregistered, which contradicts the current subchannel specification. Update the logic so that subchannels are not unregistered based on the DNV value. Also update the SCHIB information even if the DNV bit is zero. Suggested-by: Peter Oberparleiter Signed-off-by: Vineeth Vijayan Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers") Reviewed-by: Peter Oberparleiter Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/s390/cio/cio.c | 6 +++++- drivers/s390/cio/device.c | 18 +++++++++++++++++- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c index a5736b7357b2..7843c69abee6 100644 --- a/drivers/s390/cio/cio.c +++ b/drivers/s390/cio/cio.c @@ -459,10 +459,14 @@ int cio_update_schib(struct subchannel *sch) { struct schib schib; - if (stsch(sch->schid, &schib) || !css_sch_is_valid(&schib)) + if (stsch(sch->schid, &schib)) return -ENODEV; memcpy(&sch->schib, &schib, sizeof(schib)); + + if (!css_sch_is_valid(&schib)) + return -EACCES; + return 0; } EXPORT_SYMBOL_GPL(cio_update_schib); diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 34b2567b8df4..e623359862ea 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -1387,14 +1387,18 @@ enum io_sch_action { IO_SCH_VERIFY, IO_SCH_DISC, IO_SCH_NOP, + IO_SCH_ORPH_CDEV, }; static enum io_sch_action sch_get_action(struct subchannel *sch) { struct ccw_device *cdev; + int rc; cdev = sch_get_cdev(sch); - if (cio_update_schib(sch)) { + rc = cio_update_schib(sch); + + if (rc == -ENODEV) { /* Not operational. */ if (!cdev) return IO_SCH_UNREG; @@ -1402,6 +1406,16 @@ static enum io_sch_action sch_get_action(struct subchannel *sch) return IO_SCH_UNREG; return IO_SCH_ORPH_UNREG; } + + /* Avoid unregistering subchannels without working device. */ + if (rc == -EACCES) { + if (!cdev) + return IO_SCH_NOP; + if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK) + return IO_SCH_UNREG_CDEV; + return IO_SCH_ORPH_CDEV; + } + /* Operational. */ if (!cdev) return IO_SCH_ATTACH; @@ -1471,6 +1485,7 @@ static int io_subchannel_sch_event(struct subchannel *sch, int process) rc = 0; goto out_unlock; case IO_SCH_ORPH_UNREG: + case IO_SCH_ORPH_CDEV: case IO_SCH_ORPH_ATTACH: ccw_device_set_disconnected(cdev); break; @@ -1502,6 +1517,7 @@ static int io_subchannel_sch_event(struct subchannel *sch, int process) /* Handle attached ccw device. */ switch (action) { case IO_SCH_ORPH_UNREG: + case IO_SCH_ORPH_CDEV: case IO_SCH_ORPH_ATTACH: /* Move ccw device to orphanage. */ rc = ccw_device_move_to_orph(cdev);