From f551451a4b9975121424cb0837df67d31d2528dc Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Tue, 23 Jul 2019 14:45:45 +0100 Subject: [PATCH 07/14] block: Add bdrv_get_request_alignment() RH-Author: Max Reitz 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 RH-Acked-by: Stefano Garzarella RH-Acked-by: John Snow 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: Max Reitz Signed-off-by: Danilo C. L. de Paula --- 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