[Xen-changelog] [xen-unstable] Simplify include/xen/grant_table.h a bit:

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1254897890 -3600
# Node ID c14b8d395c799787039d0ebc6eac89bbcb43c7ff
# Parent  006686ed2088c92ad722f7982d19b2b34413f1ed
Simplify include/xen/grant_table.h a bit:

-- INITIAL_GRANT_ENTRIES is never used, so can be removed.
-- Simplify num_act_frames_from_sha_frames a little.

Signed-off-by: Steven Smith <steven.smith@xxxxxxxxxx>
---
 xen/include/xen/grant_table.h |   21 +++++++--------------
 1 files changed, 7 insertions(+), 14 deletions(-)

diff -r 006686ed2088 -r c14b8d395c79 xen/include/xen/grant_table.h
--- a/xen/include/xen/grant_table.h     Wed Oct 07 07:43:50 2009 +0100
+++ b/xen/include/xen/grant_table.h     Wed Oct 07 07:44:50 2009 +0100
@@ -52,10 +52,6 @@ struct active_grant_entry {
 #define GNTPIN_devr_shift    (24)
 #define GNTPIN_devr_inc      (1 << GNTPIN_devr_shift)
 #define GNTPIN_devr_mask     (0xFFU << GNTPIN_devr_shift)
-
-/* Initial size of a grant table. */
-#define INITIAL_NR_GRANT_ENTRIES ((INITIAL_NR_GRANT_FRAMES << PAGE_SHIFT) / \
-                                     sizeof(grant_entry_t))
 
 #ifndef DEFAULT_MAX_NR_GRANT_FRAMES /* to allow arch to override */
 /* Default maximum size of a grant table. [POLICY] */
@@ -128,16 +124,13 @@ num_act_frames_from_sha_frames(const uns
 num_act_frames_from_sha_frames(const unsigned int num)
 {
     /* How many frames are needed for the active grant table,
-     * given the size of the shared grant table?
-     *
-     * act_per_page = PAGE_SIZE / sizeof(active_grant_entry_t);
-     * sha_per_page = PAGE_SIZE / sizeof(grant_entry_t);
-     * num_sha_entries = num * sha_per_page;
-     * num_act_frames = (num_sha_entries + (act_per_page-1)) / act_per_page;
-     */
-    return ((num * (PAGE_SIZE / sizeof(grant_entry_t))) +
-            ((PAGE_SIZE / sizeof(struct active_grant_entry))-1))
-           / (PAGE_SIZE / sizeof(struct active_grant_entry));
+     * given the size of the shared grant table? */
+    unsigned act_per_page = PAGE_SIZE / sizeof(struct active_grant_entry);
+    unsigned sha_per_page = PAGE_SIZE / sizeof(grant_entry_t);
+    unsigned num_sha_entries = num * sha_per_page;
+    unsigned num_act_frames =
+        (num_sha_entries + (act_per_page-1)) / act_per_page;
+    return num_act_frames;
 }
 
 static inline unsigned int

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