This is a note to let you know that I've just added the patch titled
s390/cio: add dev_busid sysfs entry for each subchannel
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-cio-add-dev_busid-sysfs-entry-for-each-subchann.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 63cb87c967ace49905d4ba32eb5aa404315a6494
Author: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx>
Date: Sun Apr 25 10:52:38 2021 +0200
s390/cio: add dev_busid sysfs entry for each subchannel
[ Upstream commit d3683c055212bf910d4e318f7944910ce10dbee6 ]
Introduce dev_busid, which exports the device-id associated with the
io-subchannel (and message-subchannel). The dev_busid indicates that of
the device which may be physically installed on the corrosponding
subchannel. The dev_busid value "none" indicates that the subchannel
is not valid, there is no I/O device currently associated with the
subchannel.
The dev_busid information would be helpful to write device-specific
udev-rules associated with the subchannel. The dev_busid interface would
be available even when the sch is not bound to any driver or if there is
no operational device connected on it. Hence this attribute can be used to
write udev-rules which are specific to the device associated with the
subchannel.
Signed-off-by: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx>
Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index a974943c27da..9fcdb8d81eee 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -430,9 +430,26 @@ static ssize_t pimpampom_show(struct device *dev,
}
static DEVICE_ATTR_RO(pimpampom);
+static ssize_t dev_busid_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct subchannel *sch = to_subchannel(dev);
+ struct pmcw *pmcw = &sch->schib.pmcw;
+
+ if ((pmcw->st == SUBCHANNEL_TYPE_IO ||
+ pmcw->st == SUBCHANNEL_TYPE_MSG) && pmcw->dnv)
+ return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
+ pmcw->dev);
+ else
+ return sysfs_emit(buf, "none\n");
+}
+static DEVICE_ATTR_RO(dev_busid);
+
static struct attribute *io_subchannel_type_attrs[] = {
&dev_attr_chpids.attr,
&dev_attr_pimpampom.attr,
+ &dev_attr_dev_busid.attr,
NULL,
};
ATTRIBUTE_GROUPS(io_subchannel_type);
