From d535435f4a3968a897803d38bf1642f3b644979a Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 7 Jul 2017 07:44:43 -0500 Subject: [PATCH] stream: Switch stream_run() to byte-based We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Change the internal loop iteration of streaming to track by bytes instead of sectors (although we are still guaranteed that we iterate by steps that are sector-aligned). Signed-off-by: Eric Blake Reviewed-by: John Snow Reviewed-by: Jeff Cody Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/stream.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/block/stream.c b/block/stream.c index 12f1659942..e3dd2ac3c8 100644 --- a/block/stream.c +++ b/block/stream.c @@ -107,12 +107,11 @@ static void coroutine_fn stream_run(void *opaque) BlockBackend *blk = s->common.blk; BlockDriverState *bs = blk_bs(blk); BlockDriverState *base = s->base; - int64_t sector_num = 0; - int64_t end = -1; + int64_t offset = 0; uint64_t delay_ns = 0; int error = 0; int ret = 0; - int n = 0; + int n = 0; /* sectors */ void *buf; if (!bs->backing) { @@ -125,7 +124,6 @@ static void coroutine_fn stream_run(void *opaque) goto out; } - end = s->common.len >> BDRV_SECTOR_BITS; buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE); /* Turn on copy-on-read for the whole block device so that guest read @@ -137,7 +135,7 @@ static void coroutine_fn stream_run(void *opaque) bdrv_enable_copy_on_read(bs); } - for (sector_num = 0; sector_num < end; sector_num += n) { + for ( ; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) { bool copy; /* Note that even when no rate limit is applied we need to yield @@ -150,28 +148,26 @@ static void coroutine_fn stream_run(void *opaque) copy = false; - ret = bdrv_is_allocated(bs, sector_num, + ret = bdrv_is_allocated(bs, offset / BDRV_SECTOR_SIZE, STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); if (ret == 1) { /* Allocated in the top, no need to copy. */ } else if (ret >= 0) { /* Copy if allocated in the intermediate images. Limit to the - * known-unallocated area [sector_num, sector_num+n). */ + * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */ ret = bdrv_is_allocated_above(backing_bs(bs), base, - sector_num, n, &n); + offset / BDRV_SECTOR_SIZE, n, &n); /* Finish early if end of backing file has been reached */ if (ret == 0 && n == 0) { - n = end - sector_num; + n = (s->common.len - offset) / BDRV_SECTOR_SIZE; } copy = (ret == 1); } - trace_stream_one_iteration(s, sector_num * BDRV_SECTOR_SIZE, - n * BDRV_SECTOR_SIZE, ret); + trace_stream_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret); if (copy) { - ret = stream_populate(blk, sector_num * BDRV_SECTOR_SIZE, - n * BDRV_SECTOR_SIZE, buf); + ret = stream_populate(blk, offset, n * BDRV_SECTOR_SIZE, buf); } if (ret < 0) { BlockErrorAction action =