[Qemu-devel] [PATCH 0/5] block: remove unused emulation and synchronous functions

[Stefan Hajnoczi]

Now that the block layer processes requests in coroutine context, some of the
emulation wrappers and duplicate code paths can be dropped.  Paraphrasing a
wise man, Arnold Schwarzenegger, "I will go to the block layer and I will clean
house" :).

They key thing behind this series is that the block layer processes requests in
coroutine context and will try to use .brdv_co_readv()/.bdrv_co_writev() when
possible.  Should the BlockDriver not implement those interfaces, an emulation
function will be used to provide them using aio.  If the BlockDriver does not
implement aio interfaces, then an emulation function will be used to provide
them using synchronous I/O.

This means:

1. A BlockDriver that implements coroutine interfaces does not need to
   implement aio or synchronous interfaces.

2. A BlockDriver that implements aio interfaces does not need to implement
   synchronous interfaces.

3. Coroutine interfaces are preferred and do not require any emulation
   functions.

This patch series propagates these rules across existing BlockDrivers and
removes unused emulation functions from block.c.

Stefan Hajnoczi (5):
  block: drop emulation functions that use coroutines
  raw-posix: remove bdrv_read()/bdrv_write()
  block: use coroutine interface for raw format
  block: drop .bdrv_read()/.bdrv_write() emulation
  block: drop bdrv_has_async_rw()

 block.c           |  142 ++-------------------------
 block/raw-posix.c |  277 -----------------------------------------------------
 block/raw.c       |   32 ++-----
 3 files changed, 18 insertions(+), 433 deletions(-)

-- 
1.7.6.3