6.6-stable review patch. If anyone has any objections, please let me know.
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From: Vineeth Vijayan vneethv@linux.ibm.com
[ 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 oberpar@linux.ibm.com Signed-off-by: Vineeth Vijayan vneethv@linux.ibm.com Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers") Reviewed-by: Peter Oberparleiter oberpar@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6127add746d18..81ef9002f0640 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 57e0050dbaa53..6b374026cd4f4 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);