From: Chang Huaixin Date: Thu, 16 Oct 2014 20:33:24 +0000 (-0700) Subject: Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend X-Git-Tag: v3.18-rc1~6^2~3 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=4d544e3bdb12f8e48f61e7f2270b253a48c69e00 Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend xenkbd_disconnect_backend doesn't free grant table entry. This bug affects live migration. xenkbd_disconnect_backend uses gnttab_end_foreign_access_ref to handle grant table entry which doesn't really free an entry. Thus every time we do xenkbd_resume, grant table entry increses by one. As an grant table entry occupies 8 bytes, an grant table page has at most 512 entries. Every 512 times we do xenkdb_resume, grant table pages increses by one. After around 3500 times of live migration, grant table pages will increase by 7, causing too many pages to populate and hitting max_pages limit when assigning pages.Thus assign_pages will fail, so will live migration. Signed-off-by: Chang Huaixin Acked-by: David Vrabel Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c index fbfdc10573be..e2ecfc6e633d 100644 --- a/drivers/input/misc/xen-kbdfront.c +++ b/drivers/input/misc/xen-kbdfront.c @@ -285,7 +285,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev, error_evtchan: xenbus_free_evtchn(dev, evtchn); error_grant: - gnttab_end_foreign_access_ref(info->gref, 0); + gnttab_end_foreign_access(info->gref, 0, 0UL); info->gref = -1; return ret; } @@ -296,7 +296,7 @@ static void xenkbd_disconnect_backend(struct xenkbd_info *info) unbind_from_irqhandler(info->irq, info); info->irq = -1; if (info->gref >= 0) - gnttab_end_foreign_access_ref(info->gref, 0); + gnttab_end_foreign_access(info->gref, 0, 0UL); info->gref = -1; }