On 05/21/2012 10:32 AM, Mike Christie wrote:
> On 05/21/2012 06:45 AM, Hannes Reinecke wrote:
>> On 05/18/2012 06:56 AM, michaelc@xxxxxxxxxxx wrote:
>>> From: Mike Christie <michaelc@xxxxxxxxxxx>
>>>
>>> If a device goes offline while the device is opened then closed
>>> while it is still offline, udev will remove the /dev/disk/by-id
>>> link. If the device comes back and is set to running, userspace
>>> is not notified, and the by-id link will not get remade.
>>>
>>> This patch has scsi-ml send a KOBJ_CHANGE event so tools like udev
>>> will know that it can being to use the device again. With this patch
>>> udev see the KOBJ_CHANGE event and will reprobe the device and recreate
>>> a /dev/disk/by-id link.
>>>
>>> v2
>>> - Added SDEV_EVT_STATE_RUNNING evt type.
>>>
>>> Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
>>> ---
>>> drivers/scsi/scsi_lib.c | 9 +++++++++
>>> include/scsi/scsi_device.h | 2 ++
>>> 2 files changed, 11 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
>>> index d15b243..b54030d 100644
>>> --- a/drivers/scsi/scsi_lib.c
>>> +++ b/drivers/scsi/scsi_lib.c
>>> @@ -2061,6 +2061,7 @@ int
>>> scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
>>> {
>>> enum scsi_device_state oldstate = sdev->sdev_state;
>>> + int change_evt = 0;
>>>
>>> if (state == oldstate)
>>> return 0;
>>> @@ -2079,6 +2080,11 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
>>> switch (oldstate) {
>>> case SDEV_OFFLINE:
>>> case SDEV_TRANSPORT_OFFLINE:
>>> + /*
>>> + * Notify userspace we can accept IO by sending
>>> + * change event.
>>> + */
>>> + change_evt = 1;
>>> case SDEV_QUIESCE:
>>> case SDEV_BLOCK:
>>> case SDEV_CREATED:
>>> @@ -2160,6 +2166,8 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
>>>
>>> }
>>> sdev->sdev_state = state;
>>> + if (change_evt)
>>> + sdev_evt_send_simple(sdev, SDEV_EVT_STATE_RUNNING, GFP_ATOMIC);
>>> return 0;
>>>
>>> illegal:
>>> @@ -2283,6 +2291,7 @@ struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
>>> /* evt_type-specific initialization, if any */
>>> switch (evt_type) {
>>> case SDEV_EVT_MEDIA_CHANGE:
>>> + case SDEV_EVT_STATE_RUNNING:
>>> default:
>>> /* do nothing */
>>> break;
>> Hmm. So we're only getting notified if the device switched to OFFLINE?
>
> No from one of the offlines to running.
>
I think I know what happened. Maybe you did not reivew all the patches
at the same time. With all patches in the set applied we have this:
scsi_device_set_state()
......
case SDEV_RUNNING: <- so we are going into running
switch (oldstate) {
case SDEV_OFFLINE: <- we were in one of the offlines
case SDEV_TRANSPORT_OFFLINE:
/*
* Notify userspace we can accept IO by sending
* change event.
*/
change_evt = 1; <- so we send evt for *offline
to running transistions
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