[Qemu-devel] [PATCH v6 08/20] virtio: Switch to byte-based aio block access

[Eric Blake <eblake@redhat.com>]

Sector-based blk_aio_readv() and blk_aio_writev() should die; switch
to byte-based blk_aio_preadv() and blk_aio_pwritev() instead.

The trace is modified at the same time, and nb_sectors is now
unused.  Fix a comment typo while in the vicinity.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 hw/block/virtio-blk.c | 18 ++++++++----------
 trace-events          |  2 +-
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 3f88f8c..284e646 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -322,7 +322,6 @@ static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
 {
     QEMUIOVector *qiov = &mrb->reqs[start]->qiov;
     int64_t sector_num = mrb->reqs[start]->sector_num;
-    int nb_sectors = mrb->reqs[start]->qiov.size / BDRV_SECTOR_SIZE;
     bool is_write = mrb->is_write;

     if (num_reqs > 1) {
@@ -331,7 +330,7 @@ static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
         int tmp_niov = qiov->niov;

         /* mrb->reqs[start]->qiov was initialized from external so we can't
-         * modifiy it here. We need to initialize it locally and then add the
+         * modify it here. We need to initialize it locally and then add the
          * external iovecs. */
         qemu_iovec_init(qiov, niov);

@@ -343,23 +342,22 @@ static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
             qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0,
                               mrb->reqs[i]->qiov.size);
             mrb->reqs[i - 1]->mr_next = mrb->reqs[i];
-            nb_sectors += mrb->reqs[i]->qiov.size / BDRV_SECTOR_SIZE;
         }
-        assert(nb_sectors == qiov->size / BDRV_SECTOR_SIZE);

-        trace_virtio_blk_submit_multireq(mrb, start, num_reqs, sector_num,
-                                         nb_sectors, is_write);
+        trace_virtio_blk_submit_multireq(mrb, start, num_reqs,
+                                         sector_num << BDRV_SECTOR_BITS,
+                                         qiov->size, is_write);
         block_acct_merge_done(blk_get_stats(blk),
                               is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ,
                               num_reqs - 1);
     }

     if (is_write) {
-        blk_aio_writev(blk, sector_num, qiov, nb_sectors,
+        blk_aio_pwritev(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0,
+                        virtio_blk_rw_complete, mrb->reqs[start]);
+    } else {
+        blk_aio_preadv(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0,
                        virtio_blk_rw_complete, mrb->reqs[start]);
-    } else {
-        blk_aio_readv(blk, sector_num, qiov, nb_sectors,
-                      virtio_blk_rw_complete, mrb->reqs[start]);
     }
 }

diff --git a/trace-events b/trace-events
index b4acd2a..b588091 100644
--- a/trace-events
+++ b/trace-events
@@ -118,7 +118,7 @@ virtio_blk_req_complete(void *req, int status) "req %p status %d"
 virtio_blk_rw_complete(void *req, int ret) "req %p ret %d"
 virtio_blk_handle_write(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
 virtio_blk_handle_read(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
-virtio_blk_submit_multireq(void *mrb, int start, int num_reqs, uint64_t sector, size_t nsectors, bool is_write) "mrb %p start %d num_reqs %d sector %"PRIu64" nsectors %zu is_write %d"
+virtio_blk_submit_multireq(void *mrb, int start, int num_reqs, uint64_t offset, size_t size, bool is_write) "mrb %p start %d num_reqs %d offset %"PRIu64" size %zu is_write %d"

 # hw/block/dataplane/virtio-blk.c
 virtio_blk_data_plane_start(void *s) "dataplane %p"
-- 
2.5.5