xen: add grant interface version dependent constants to gnttab_ops

Instead of having multiple variables with constants like
grant_table_version or grefs_per_grant_frame add those to struct
gnttab_ops and access them just via the gnttab_interface pointer.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 43 insertions, 30 deletions

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index db6a1b9efd11..573e7fe9b147 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -78,6 +78,14 @@ static union {
 /*This is a structure of function pointers for grant table*/
 struct gnttab_ops {
         /*
+         * Version of the grant interface.
+         */
+        unsigned int version;
+        /*
+         * Grant refs per grant frame.
+         */
+        unsigned int grefs_per_grant_frame;
+        /*
          * Mapping a list of frames for storing grant entries. Frames parameter
          * is used to store grant table address when grant table being setup,
          * nr_gframes is the number of frames to map grant table. Returning
@@ -134,9 +142,6 @@ static const struct gnttab_ops *gnttab_interface;
 /* This reflects status of grant entries, so act as a global value. */
 static grant_status_t *grstatus;
 
-static int grant_table_version;
-static int grefs_per_grant_frame;
-
 static struct gnttab_free_callback *gnttab_free_callback_list;
 
 static int gnttab_expand(unsigned int req_entries);
@@ -636,19 +641,26 @@ void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
 }
 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
 
+static unsigned int gnttab_frames(unsigned int frames, unsigned int align)
+{
+        return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
+               align;
+}
+
 static int grow_gnttab_list(unsigned int more_frames)
 {
         unsigned int new_nr_grant_frames, extra_entries, i;
         unsigned int nr_glist_frames, new_nr_glist_frames;
+        unsigned int grefs_per_frame;
 
-        BUG_ON(grefs_per_grant_frame == 0);
+        BUG_ON(gnttab_interface == NULL);
+        grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 
         new_nr_grant_frames = nr_grant_frames + more_frames;
-        extra_entries       = more_frames * grefs_per_grant_frame;
+        extra_entries = more_frames * grefs_per_frame;
 
-        nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
-        new_nr_glist_frames =
-                (new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
+        nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
+        new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, RPP);
         for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
                 if (!gnttab_list[i])
@@ -656,12 +668,12 @@ static int grow_gnttab_list(unsigned int more_frames)
         }
 
 
-        for (i = grefs_per_grant_frame * nr_grant_frames;
-             i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
+        for (i = grefs_per_frame * nr_grant_frames;
+             i < grefs_per_frame * new_nr_grant_frames - 1; i++)
                 gnttab_entry(i) = i + 1;
 
         gnttab_entry(i) = gnttab_free_head;
-        gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
+        gnttab_free_head = grefs_per_frame * nr_grant_frames;
         gnttab_free_count += extra_entries;
 
         nr_grant_frames = new_nr_grant_frames;
@@ -1013,8 +1025,8 @@ EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
 
 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
 {
-        BUG_ON(grefs_per_grant_frame == 0);
-        return (nr_grant_frames * grefs_per_grant_frame + SPP - 1) / SPP;
+        BUG_ON(gnttab_interface == NULL);
+        return gnttab_frames(nr_grant_frames, SPP);
 }
 
 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
@@ -1142,6 +1154,9 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 }
 
 static const struct gnttab_ops gnttab_v1_ops = {
+        .version                        = 1,
+        .grefs_per_grant_frame          = XEN_PAGE_SIZE /
+                                          sizeof(struct grant_entry_v1),
         .map_frames                     = gnttab_map_frames_v1,
         .unmap_frames                   = gnttab_unmap_frames_v1,
         .update_entry                   = gnttab_update_entry_v1,
@@ -1151,6 +1166,9 @@ static const struct gnttab_ops gnttab_v1_ops = {
 };
 
 static const struct gnttab_ops gnttab_v2_ops = {
+        .version                        = 2,
+        .grefs_per_grant_frame          = XEN_PAGE_SIZE /
+                                          sizeof(union grant_entry_v2),
         .map_frames                     = gnttab_map_frames_v2,
         .unmap_frames                   = gnttab_unmap_frames_v2,
         .update_entry                   = gnttab_update_entry_v2,
@@ -1167,18 +1185,12 @@ static void gnttab_request_version(void)
         gsv.version = 1;
 
         rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
-        if (rc == 0 && gsv.version == 2) {
-                grant_table_version = 2;
-                grefs_per_grant_frame = XEN_PAGE_SIZE /
-                                        sizeof(union grant_entry_v2);
+        if (rc == 0 && gsv.version == 2)
                 gnttab_interface = &gnttab_v2_ops;
-        } else {
-                grant_table_version = 1;
-                grefs_per_grant_frame = XEN_PAGE_SIZE /
-                                        sizeof(struct grant_entry_v1);
+        else
                 gnttab_interface = &gnttab_v1_ops;
-        }
-        pr_info("Grant tables using version %d layout\n", grant_table_version);
+        pr_info("Grant tables using version %d layout\n",
+                gnttab_interface->version);
 }
 
 static int gnttab_setup(void)
@@ -1218,10 +1230,10 @@ static int gnttab_expand(unsigned int req_entries)
         int rc;
         unsigned int cur, extra;
 
-        BUG_ON(grefs_per_grant_frame == 0);
+        BUG_ON(gnttab_interface == NULL);
         cur = nr_grant_frames;
-        extra = ((req_entries + (grefs_per_grant_frame-1)) /
-                 grefs_per_grant_frame);
+        extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
+                 gnttab_interface->grefs_per_grant_frame);
         if (cur + extra > gnttab_max_grant_frames()) {
                 pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
                                     " cur=%u extra=%u limit=%u"
@@ -1253,16 +1265,16 @@ int gnttab_init(void)
         /* Determine the maximum number of frames required for the
          * grant reference free list on the current hypervisor.
          */
-        BUG_ON(grefs_per_grant_frame == 0);
+        BUG_ON(gnttab_interface == NULL);
         max_nr_glist_frames = (max_nr_grant_frames *
-                               grefs_per_grant_frame / RPP);
+                               gnttab_interface->grefs_per_grant_frame / RPP);
 
         gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
                               GFP_KERNEL);
         if (gnttab_list == NULL)
                 return -ENOMEM;
 
-        nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
+        nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
         for (i = 0; i < nr_glist_frames; i++) {
                 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
                 if (gnttab_list[i] == NULL) {
@@ -1281,7 +1293,8 @@ int gnttab_init(void)
                 goto ini_nomem;
         }
 
-        nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
+        nr_init_grefs = nr_grant_frames *
+                        gnttab_interface->grefs_per_grant_frame;
 
         for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
                 gnttab_entry(i) = i + 1;