Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu in…

…to staging

Pull request

# -----BEGIN PGP SIGNATURE-----
#
# iQEzBAABCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmNZg14ACgkQnKSrs4Gr
# c8hwwwf/Udbnt6n4SShezEIYRe0udLvuyo1HwcMNLWjllHLfp/yNDcPsGk+r13Ue
# TxrvbVaucxB5RPdN67KmzPyu+wPM/o0nij7c4CkBvwNPXmfUCF97Lj0prEL+ZeHp
# HmNg08FRfHM2vKMFyJXqDAidBecUDizLrP9C3nc/LAF6fr9ds+vfFuB/12eSXvZ+
# RLnaAj7KLt2MzkgWbDiC6066TPZWCcwFJmc0zkCAthCepokDrKfSHc+0u9U/NXA9
# Qv7qKcEBYq3vP3SCvDtbKU3Ig4CoiwO3A3O9wZTypamU2816H9HtEJ5NPtjNUFPF
# dm3siyKODbDx4mzba/Xv/26lHGSsJA==
# =bmGV
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 26 Oct 2022 14:58:38 EDT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [ultimate]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [ultimate]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* tag 'block-pull-request' of https://gitlab.com/stefanha/qemu:
  virtio-blk: use BDRV_REQ_REGISTERED_BUF optimization hint
  blkio: implement BDRV_REQ_REGISTERED_BUF optimization
  stubs: add qemu_ram_block_from_host() and qemu_ram_get_fd()
  exec/cpu-common: add qemu_ram_get_fd()
  block: add BlockRAMRegistrar
  numa: use QLIST_FOREACH_SAFE() for RAM block notifiers
  block: return errors from bdrv_register_buf()
  block: add BDRV_REQ_REGISTERED_BUF request flag
  block: use BdrvRequestFlags type for supported flag fields
  block: pass size to bdrv_unregister_buf()
  numa: call ->ram_block_removed() in ram_block_notifer_remove()
  blkio: add libblkio block driver
  coroutine: add flag to re-queue at front of CoQueue

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

MAINTAINERS

@@ -2510,6 +2510,7 @@ F: block*
 F: block/
 F: hw/block/
 F: include/block/
+F: include/sysemu/block-*.h
 F: qemu-img*
 F: docs/tools/qemu-img.rst
 F: qemu-io*
@@ -3415,6 +3416,12 @@ L: qemu-block@nongnu.org
 S: Maintained
 F: block/vdi.c
 
+blkio
+M: Stefan Hajnoczi <stefanha@redhat.com>
+L: qemu-block@nongnu.org
+S: Maintained
+F: block/blkio.c
+
 iSCSI
 M: Ronnie Sahlberg <ronniesahlberg@gmail.com>
 M: Paolo Bonzini <pbonzini@redhat.com>

block.c

@@ -1641,6 +1641,20 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
         goto open_failed;
     }
 
+    assert(!(bs->supported_read_flags & ~BDRV_REQ_MASK));
+    assert(!(bs->supported_write_flags & ~BDRV_REQ_MASK));
+
+    /*
+     * Always allow the BDRV_REQ_REGISTERED_BUF optimization hint. This saves
+     * drivers that pass read/write requests through to a child the trouble of
+     * declaring support explicitly.
+     *
+     * Drivers must not propagate this flag accidentally when they initiate I/O
+     * to a bounce buffer. That case should be rare though.
+     */
+    bs->supported_read_flags |= BDRV_REQ_REGISTERED_BUF;
+    bs->supported_write_flags |= BDRV_REQ_REGISTERED_BUF;
+
     ret = refresh_total_sectors(bs, bs->total_sectors);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Could not refresh total sector count");