vmw_balloon: fix inflation with batching

BugLink: http://bugs.launchpad.net/bugs/1810554
commit 90d72ce079791399ac255c75728f3c9e747b093d upstream.

Embarrassingly, the recent fix introduced worse problem than it solved,
causing the balloon not to inflate. The VM informed the hypervisor that
the pages for lock/unlock are sitting in the wrong address, as it used
the page that is used the uninitialized page variable.

Fixes: b23220fe054e9 ("vmw_balloon: fixing double free when batching mode is off")
Cc: stable@vger.kernel.org
Reviewed-by: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index efd733472a3531804225c5515ade4f4cf69fd707..56c6f79a5c5af83a862cf76352f172f5e02ee0b8 100644 (file)
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -467,7 +467,7 @@ static int vmballoon_send_batched_lock(struct vmballoon *b,
                unsigned int num_pages, bool is_2m_pages, unsigned int *target)
 {
        unsigned long status;
-       unsigned long pfn = page_to_pfn(b->page);
+       unsigned long pfn = PHYS_PFN(virt_to_phys(b->batch_page));
 
        STATS_INC(b->stats.lock[is_2m_pages]);
 
@@ -515,7 +515,7 @@ static bool vmballoon_send_batched_unlock(struct vmballoon *b,
                unsigned int num_pages, bool is_2m_pages, unsigned int *target)
 {
        unsigned long status;
-       unsigned long pfn = page_to_pfn(b->page);
+       unsigned long pfn = PHYS_PFN(virt_to_phys(b->batch_page));
 
        STATS_INC(b->stats.unlock[is_2m_pages]);