From f551451a4b9975121424cb0837df67d31d2528dc Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Tue, 23 Jul 2019 14:45:45 +0100

Subject: [PATCH 07/14] block: Add bdrv_get_request_alignment()

RH-Author: Max Reitz <mreitz@redhat.com>

Message-id: <20190723144546.23701-7-mreitz@redhat.com>

Patchwork-id: 89653

O-Subject: [RHEL-8.1.0 qemu-kvm PATCH 6/7] block: Add bdrv_get_request_alignment()

Bugzilla: 1678979

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>

RH-Acked-by: John Snow <jsnow@redhat.com>

From: Eric Blake <eblake@redhat.com>

The next patch needs access to a device's minimum permitted

alignment, since NBD wants to advertise this to clients. Add

an accessor function, borrowing from blk_get_max_transfer()

for accessing a backend's block limits.

Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Message-Id: <20190329042750.14704-6-eblake@redhat.com>

(cherry picked from commit 4841211e0d1628cd386b35835676d7f6f9a4fa9d)

Signed-off-by: Max Reitz <mreitz@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 block/block-backend.c          | 7 +++++++

 include/sysemu/block-backend.h | 1 +

 2 files changed, 8 insertions(+)

diff --git a/block/block-backend.c b/block/block-backend.c

index 7ae5832..0d623e4 100644

--- a/block/block-backend.c

+++ b/block/block-backend.c

@@ -1807,6 +1807,13 @@ int blk_get_flags(BlockBackend *blk)

     }

 }

+/* Returns the minimum request alignment, in bytes; guaranteed nonzero */

+uint32_t blk_get_request_alignment(BlockBackend *blk)

+{

+    BlockDriverState *bs = blk_bs(blk);

+    return bs ? bs->bl.request_alignment : BDRV_SECTOR_SIZE;

+}

+

 /* Returns the maximum transfer length, in bytes; guaranteed nonzero */

 uint32_t blk_get_max_transfer(BlockBackend *blk)

 {

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h

index 830d873..20f8bbb 100644

--- a/include/sysemu/block-backend.h

+++ b/include/sysemu/block-backend.h

@@ -176,6 +176,7 @@ bool blk_is_available(BlockBackend *blk);

 void blk_lock_medium(BlockBackend *blk, bool locked);

 void blk_eject(BlockBackend *blk, bool eject_flag);

 int blk_get_flags(BlockBackend *blk);

+uint32_t blk_get_request_alignment(BlockBackend *blk);

 uint32_t blk_get_max_transfer(BlockBackend *blk);

 int blk_get_max_iov(BlockBackend *blk);

 void blk_set_guest_block_size(BlockBackend *blk, int align);

-- 

1.8.3.1