blockdev: Don't limit DriveInfo serial to 20 characters

All current users (IDE, SCSI and virtio-blk) happen to share this 20
characters limit.  Still, it should be left to device models.  They
already enforce their limits.  They have to, as the DriveInfo limit
only affects legacy -drive serial=..., not the qdev properties.

usb-storage, which doesn't limit serial number length, also uses
DriveInfo for -usbdevice.  But that doesn't provide access to
DriveInfo serial.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev.c

@@ -536,9 +536,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
     dinfo->trans = translation;
     dinfo->opts = opts;
     dinfo->refcount = 1;
-    if (serial) {
-        pstrcpy(dinfo->serial, sizeof(dinfo->serial), serial);
-    }
+    dinfo->serial = serial;
     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 
     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);

blockdev.h

@@ -17,8 +17,6 @@
 void blockdev_mark_auto_del(BlockDriverState *bs);
 void blockdev_auto_del(BlockDriverState *bs);
 
-#define BLOCK_SERIAL_STRLEN 20
-
 typedef enum {
     IF_DEFAULT = -1,            /* for use with drive_add() only */
     IF_NONE,
@@ -37,7 +35,7 @@ struct DriveInfo {
     int media_cd;
     int cyls, heads, secs, trans;
     QemuOpts *opts;
-    char serial[BLOCK_SERIAL_STRLEN + 1];
+    const char *serial;
     QTAILQ_ENTRY(DriveInfo) next;
     int refcount;
 };

hw/block-common.c

@@ -17,7 +17,7 @@ void blkconf_serial(BlockConf *conf, char **serial)
     if (!*serial) {
         /* try to fall back to value set with legacy -drive serial=... */
         dinfo = drive_get_by_blockdev(conf->bs);
-        if (*dinfo->serial) {
+        if (dinfo->serial) {
             *serial = g_strdup(dinfo->serial);
         }
     }

hw/ide/core.c

@@ -2095,9 +2095,9 @@ void ide_init2_with_non_qdev_drives(IDEBus *bus, DriveInfo *hd0,
                 trans = hd_bios_chs_auto_trans(cyls, heads, secs);
             }
             if (ide_init_drive(&bus->ifs[i], dinfo->bdrv,
-                               dinfo->media_cd ? IDE_CD : IDE_HD, NULL,
-                               *dinfo->serial ? dinfo->serial : NULL,
-                               NULL, 0, cyls, heads, secs, trans) < 0) {
+                               dinfo->media_cd ? IDE_CD : IDE_HD,
+                               NULL, dinfo->serial, NULL, 0,
+                               cyls, heads, secs, trans) < 0) {
                 error_report("Can't set up IDE drive %s", dinfo->id);
                 exit(1);
             }