xen/balloon: ensure preemption is disabled when using a scratch page
authorDavid Vrabel <david.vrabel@citrix.com>
Wed, 11 Sep 2013 17:45:44 +0000 (17:45 +0000)
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>
Wed, 11 Sep 2013 17:52:58 +0000 (17:52 +0000)
commit2bad07ce28a0f61c1e776f99aa05f85e4e689e24
treeb13abf74f1f22eaf3d71e5c399c599f72fd77c82
parentc3b7cb1fd8c1513be99fb3cfb7f39c5116d80dac
xen/balloon: ensure preemption is disabled when using a scratch page

In decrease_reservation(), if the kernel is preempted between updating
the mapping and updating the p2m then they may end up using different
scratch pages.

Use get_balloon_scratch_page() and put_balloon_scratch_page() which use
get_cpu_var() and put_cpu_var() to correctly disable preemption.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
drivers/xen/balloon.c