tree 9c1b768d2871b181bcc21d89bedf9bf9dbc6d998
parent 1ddbe94eda58597cb6dd464b455cb62d3f68be7b
author Alex Elder <elder@dreamhost.com> 1327867064 -0600
committer Alex Elder <elder@dreamhost.com> 1332431267 -0500

rbd: protect the rbd_dev_list with a spinlock

The rbd_dev_list is just a simple list of all the current
rbd_devices.  Using the ctl_mutex as a concurrency guard is
overkill.  Instead, use a spinlock for that specific purpose.

This also reduces the window that the ctl_mutex needs to be held in
rbd_add().

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>