From 52ebcb268273de217510bc9ed688c23894ae32a2 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 25 Jul 2018 13:20:32 +0200 Subject: [PATCH] block: Fix documentation for BDRV_REQ_MAY_UNMAP BDRV_REQ_MAY_UNMAP in a write_zeroes request does not only allow the driver to unmap the blocks, but it actively requests that the blocks be unmapped afterwards if at all possible. Signed-off-by: Kevin Wolf --- include/block/block.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index f85e3a6ed3..4e0871aaf9 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -43,11 +43,12 @@ typedef struct BlockFragInfo { typedef enum { BDRV_REQ_COPY_ON_READ = 0x1, BDRV_REQ_ZERO_WRITE = 0x2, - /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver - * is allowed to optimize a write zeroes request by unmapping (discarding) - * blocks if it is guaranteed that the result will read back as - * zeroes. The flag is only passed to the driver if the block device is - * opened with BDRV_O_UNMAP. + + /* + * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate + * that the block driver should unmap (discard) blocks if it is guaranteed + * that the result will read back as zeroes. The flag is only passed to the + * driver if the block device is opened with BDRV_O_UNMAP. */ BDRV_REQ_MAY_UNMAP = 0x4,