[PULL,1/9] migration: Make sure that we pass the right cache size

Commit Message

Juan Quintela Oct. 29, 2017, 1:09 p.m. UTC

Instead of passing silently round down the number of pages, make it an
error that the cache size is not a power of 2.

Signed-off-by: Juan Quintela <[e-mail]>
Reviewed-by: Dr. David Alan Gilbert <[e-mail]>
---
 migration/page_cache.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

Patch

diff --git a/migration/page_cache.c b/migration/page_cache.c
index 9a9d13d6a2..96268c3aea 100644
--- a/migration/page_cache.c
+++ b/migration/page_cache.c
@@ -58,6 +58,13 @@  PageCache *cache_init(int64_t new_size, size_t page_size, Error **errp)
         return NULL;
     }
 
+    /* round down to the nearest power of 2 */
+    if (!is_power_of_2(num_pages)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
+                   "is not a power of two number of pages");
+        return NULL;
+    }
+
     /* We prefer not to abort if there is no memory */
     cache = g_try_malloc(sizeof(*cache));
     if (!cache) {
@@ -65,11 +72,6 @@  PageCache *cache_init(int64_t new_size, size_t page_size, Error **errp)
                    "Failed to allocate cache");
         return NULL;
     }
-    /* round down to the nearest power of 2 */
-    if (!is_power_of_2(num_pages)) {
-        num_pages = pow2floor(num_pages);
-        DPRINTF("rounding down to %" PRId64 "\n", num_pages);
-    }
     cache->page_size = page_size;
     cache->num_items = 0;
     cache->max_num_items = num_pages;