From c4d49803aeb1d6304c2728cb1475f8314ae1f8a8 Mon Sep 17 00:00:00 2001 From: John Snow Date: Mon, 6 May 2019 17:56:22 +0200 Subject: [PATCH 12/53] block: Add bdrv_get_request_alignment() RH-Author: John Snow Message-id: <20190506175629.11079-13-jsnow@redhat.com> Patchwork-id: 87195 O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 12/19] block: Add bdrv_get_request_alignment() Bugzilla: 1692018 RH-Acked-by: Max Reitz RH-Acked-by: Stefano Garzarella RH-Acked-by: Thomas Huth From: Eric Blake 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 Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20190329042750.14704-6-eblake@redhat.com> (cherry picked from commit 4841211e0d1628cd386b35835676d7f6f9a4fa9d) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- 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 52eebeb..f6480f6 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1834,6 +1834,13 @@ 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 6b6d882..815b6e5 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -178,6 +178,7 @@ 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