Make qemu_mempath_getpagesize() accept NULL

qemu_mempath_getpagesize() gets the effective (host side) page size for
a block of memory backed by an mmap()ed file on the host.  It requires
the mem_path parameter to be non-NULL.

This ends up meaning all the callers need a different case for handling
anonymous memory (for memory-backend-ram or default memory with -mem-path
is not specified).

We can make all those callers a little simpler by having
qemu_mempath_getpagesize() accept NULL, and treat that as the anonymous
memory case.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 2fd8cbc..fd329ec 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -50,19 +50,21 @@ size_t qemu_mempath_getpagesize(const char *mem_path)
     struct statfs fs;
     int ret;
 
-    do {
-        ret = statfs(mem_path, &fs);
-    } while (ret != 0 && errno == EINTR);
-
-    if (ret != 0) {
-        fprintf(stderr, "Couldn't statfs() memory path: %s\n",
-                strerror(errno));
-        exit(1);
-    }
+    if (mem_path) {
+        do {
+            ret = statfs(mem_path, &fs);
+        } while (ret != 0 && errno == EINTR);
 
-    if (fs.f_type == HUGETLBFS_MAGIC) {
-        /* It's hugepage, return the huge page size */
-        return fs.f_bsize;
+        if (ret != 0) {
+            fprintf(stderr, "Couldn't statfs() memory path: %s\n",
+                    strerror(errno));
+            exit(1);
+        }
+
+        if (fs.f_type == HUGETLBFS_MAGIC) {
+            /* It's hugepage, return the huge page size */
+            return fs.f_bsize;
+        }
     }
 #ifdef __sparc__
     /* SPARC Linux needs greater alignment than the pagesize */