block: remove unused bdrv_media_changed

This function is not used anywhere, so remove it.

Markus Armbruster adds:
The i82078 floppy device model used to call bdrv_media_changed() to
implement its media change bit when backed by a host floppy.  This
went away in 21fcf36 "fdc: simplify media change handling".
Probably broke host floppy media change.  Host floppy pass-through
was dropped in commit f709623.  bdrv_media_changed() has never been
used for anything else.  Remove it.
(Source is Message-ID: <87y3ruaypm.fsf@dusky.pond.sub.org>)

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -4191,20 +4191,6 @@ bool bdrv_is_inserted(BlockDriverState *bs)
     return true;
 }
 
-/**
- * Return whether the media changed since the last call to this
- * function, or -ENOTSUP if we don't know.  Most drivers don't know.
- */
-int bdrv_media_changed(BlockDriverState *bs)
-{
-    BlockDriver *drv = bs->drv;
-
-    if (drv && drv->bdrv_media_changed) {
-        return drv->bdrv_media_changed(bs);
-    }
-    return -ENOTSUP;
-}
-
 /**
  * If eject_flag is TRUE, eject the media. Otherwise, close the tray
  */

block/raw-format.c

@@ -372,11 +372,6 @@ static int raw_truncate(BlockDriverState *bs, int64_t offset,
     return bdrv_truncate(bs->file, offset, prealloc, errp);
 }
 
-static int raw_media_changed(BlockDriverState *bs)
-{
-    return bdrv_media_changed(bs->file->bs);
-}
-
 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 {
     bdrv_eject(bs->file->bs, eject_flag);
@@ -510,7 +505,6 @@ BlockDriver bdrv_raw = {
     .bdrv_refresh_limits  = &raw_refresh_limits,
     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
     .bdrv_probe_geometry  = &raw_probe_geometry,
-    .bdrv_media_changed   = &raw_media_changed,
     .bdrv_eject           = &raw_eject,
     .bdrv_lock_medium     = &raw_lock_medium,
     .bdrv_co_ioctl        = &raw_co_ioctl,

include/block/block.h

@@ -441,7 +441,6 @@ int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
 bool bdrv_is_sg(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
-int bdrv_media_changed(BlockDriverState *bs);
 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);

include/block/block_int.h

@@ -248,7 +248,6 @@ struct BlockDriver {
 
     /* removable device specific */
     bool (*bdrv_is_inserted)(BlockDriverState *bs);
-    int (*bdrv_media_changed)(BlockDriverState *bs);
     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);