g_malloc(0) and g_malloc0(0) return NULL; simplify

Once upon a time, it was decided that qemu_malloc(0) should abort.
Switching to glib retired that bright idea.  Some code that was added
to cope with it (e.g. in commits 702ef63, b76b6e9) is still around.
Bury it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

4 files changed, 5 insertions, 18 deletions

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 6a95aa6..bc1784c 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -737,11 +737,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
      * l1_table_offset when it is the current s->l1_table_offset! Be careful
      * when changing this! */
     if (l1_table_offset != s->l1_table_offset) {
-        if (l1_size2 != 0) {
-            l1_table = g_malloc0(align_offset(l1_size2, 512));
-        } else {
-            l1_table = NULL;
-        }
+        l1_table = g_malloc0(align_offset(l1_size2, 512));
         l1_allocated = 1;
         if (bdrv_pread(bs->file, l1_table_offset,
                        l1_table, l1_size2) != l1_size2)
diff --git a/block/vdi.c b/block/vdi.c
index 257a592..87c691b 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -443,9 +443,7 @@ static int vdi_open(BlockDriverState *bs, int flags)
 
     bmap_size = header.blocks_in_image * sizeof(uint32_t);
     bmap_size = (bmap_size + SECTOR_SIZE - 1) / SECTOR_SIZE;
-    if (bmap_size > 0) {
-        s->bmap = g_malloc(bmap_size * SECTOR_SIZE);
-    }
+    s->bmap = g_malloc(bmap_size * SECTOR_SIZE);
     ret = bdrv_read(bs->file, s->bmap_sector, (uint8_t *)s->bmap, bmap_size);
     if (ret < 0) {
         goto fail_free_bmap;
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 0aaf0d2..b795839 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -3101,11 +3101,7 @@ static void v9fs_xattrcreate(void *opaque)
     xattr_fidp->fs.xattr.flags = flags;
     v9fs_string_init(&xattr_fidp->fs.xattr.name);
     v9fs_string_copy(&xattr_fidp->fs.xattr.name, &name);
-    if (size) {
-        xattr_fidp->fs.xattr.value = g_malloc(size);
-    } else {
-        xattr_fidp->fs.xattr.value = NULL;
-    }
+    xattr_fidp->fs.xattr.value = g_malloc(size);
     err = offset;
     put_fid(pdu, file_fidp);
 out_nofid:
diff --git a/hw/vhost.c b/hw/vhost.c
index cee8aad..0dd2a9a 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -269,11 +269,8 @@ static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
     vhost_log_chunk_t *log;
     uint64_t log_base;
     int r, i;
-    if (size) {
-        log = g_malloc0(size * sizeof *log);
-    } else {
-        log = NULL;
-    }
+
+    log = g_malloc0(size * sizeof *log);
     log_base = (uint64_t)(unsigned long)log;
     r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
     assert(r >= 0);