diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2017-01-17 00:05:59 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2017-06-19 18:03:49 +0300 |
| commit | 93e6442c76a0d26ad028c5df9b4a1e3096d9c36b (patch) | |
| tree | 50cb9b89d834e3b3c4e65189d0a3f1f85303cb0b /drivers/md/dm.c | |
| parent | 443bd90f2cca9dec3db9ef9460a9c2a6f095f789 (diff) | |
| download | linux-93e6442c76a0d26ad028c5df9b4a1e3096d9c36b.tar.xz | |
dm: add basic support for using the select or poll function
Add the ability to poll on the /dev/mapper/control device. The select
or poll function waits until any event happens on any dm device since
opening the /dev/mapper/control device. When select or poll returns the
device as readable, we must close and reopen the device to wait for new
dm events.
Usage:
1. open the /dev/mapper/control device
2. scan the event numbers of all devices we are interested in and process
them
3. call select, poll or epoll on the handle (it waits until some new event
happens since opening the device)
4. close the /dev/mapper/control handle
5. go to step 1
The next commit allows to re-arm the polling without closing and
reopening the device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index fbd06b9f9467..ff22aa2a07b5 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -58,6 +58,9 @@ static DECLARE_WORK(deferred_remove_work, do_deferred_remove); static struct workqueue_struct *deferred_remove_workqueue; +atomic_t dm_global_event_nr = ATOMIC_INIT(0); +DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq); + /* * One of these is allocated per bio. */ @@ -1760,7 +1763,9 @@ static void event_callback(void *context) dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); atomic_inc(&md->event_nr); + atomic_inc(&dm_global_event_nr); wake_up(&md->eventq); + wake_up(&dm_global_eventq); } /* |