xen/grants: Remove gnttab_max_grant_frames dependency on gnttab_init.

The function gnttab_max_grant_frames() returns the maximum amount
of frames (pages) of grants we can have. Unfortunatly it was
dependent on gnttab_init() having been run before to initialize
the boot max value (boot_max_nr_grant_frames).

This meant that users of gnttab_max_grant_frames would always
get a zero value if they called before gnttab_init() - such as
'platform_pci_init' (drivers/xen/platform-pci.c).

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index aa846a48f4009eaac8271a8a653716c27aa1dc01..99399cb0fd1cb2ad9cb4d195cd02cebc5ade748d 100644 (file)
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -62,7 +62,6 @@
 
 static grant_ref_t **gnttab_list;
 static unsigned int nr_grant_frames;
-static unsigned int boot_max_nr_grant_frames;
 static int gnttab_free_count;
 static grant_ref_t gnttab_free_head;
 static DEFINE_SPINLOCK(gnttab_list_lock);
@@ -827,6 +826,11 @@ static unsigned int __max_nr_grant_frames(void)
 unsigned int gnttab_max_grant_frames(void)
 {
        unsigned int xen_max = __max_nr_grant_frames();
+       static unsigned int boot_max_nr_grant_frames;
+
+       /* First time, initialize it properly. */
+       if (!boot_max_nr_grant_frames)
+               boot_max_nr_grant_frames = __max_nr_grant_frames();
 
        if (xen_max > boot_max_nr_grant_frames)
                return boot_max_nr_grant_frames;
@@ -1227,13 +1231,12 @@ int gnttab_init(void)
 
        gnttab_request_version();
        nr_grant_frames = 1;
-       boot_max_nr_grant_frames = __max_nr_grant_frames();
 
        /* Determine the maximum number of frames required for the
         * grant reference free list on the current hypervisor.
         */
        BUG_ON(grefs_per_grant_frame == 0);
-       max_nr_glist_frames = (boot_max_nr_grant_frames *
+       max_nr_glist_frames = (gnttab_max_grant_frames() *
                               grefs_per_grant_frame / RPP);
 
        gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),