[Qemu-devel] [PATCH v2 12/19] iscsi: Switch .bdrv_co_discard() to byte-based

[Eric Blake <eblake@redhat.com>]

Another step towards killing off sector-based block APIs.

Unlike write_zeroes, where we can be handed unaligned requests
and must fail gracefully with -ENOTSUP for a fallback, we are
guaranteed that discard requests are always aligned because the
block layer already ignored unaligned head/tail.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/iscsi.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index bdc7ade..da509df 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -923,29 +923,26 @@ iscsi_getlength(BlockDriverState *bs)
 }

 static int
-coroutine_fn iscsi_co_discard(BlockDriverState *bs, int64_t sector_num,
-                                   int nb_sectors)
+coroutine_fn iscsi_co_pdiscard(BlockDriverState *bs, int64_t offset, int count)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     struct unmap_list list;

-    if (!is_sector_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
-        return -EINVAL;
-    }
+    assert(is_byte_request_lun_aligned(offset, count, iscsilun));

     if (!iscsilun->lbp.lbpu) {
         /* UNMAP is not supported by the target */
         return 0;
     }

-    list.lba = sector_qemu2lun(sector_num, iscsilun);
-    list.num = sector_qemu2lun(nb_sectors, iscsilun);
+    list.lba = offset / iscsilun->block_size;
+    list.num = count / iscsilun->block_size;

     iscsi_co_init_iscsitask(iscsilun, &iTask);
 retry:
     if (iscsi_unmap_task(iscsilun->iscsi, iscsilun->lun, 0, 0, &list, 1,
-                     iscsi_co_generic_cb, &iTask) == NULL) {
+                         iscsi_co_generic_cb, &iTask) == NULL) {
         return -ENOMEM;
     }

@@ -975,7 +972,8 @@ retry:
         return iTask.err_code;
     }

-    iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors);
+    iscsi_allocationmap_clear(iscsilun, offset >> BDRV_SECTOR_BITS,
+                              count >> BDRV_SECTOR_BITS);

     return 0;
 }
@@ -1862,7 +1860,7 @@ static BlockDriver bdrv_iscsi = {
     .bdrv_refresh_limits = iscsi_refresh_limits,

     .bdrv_co_get_block_status = iscsi_co_get_block_status,
-    .bdrv_co_discard      = iscsi_co_discard,
+    .bdrv_co_pdiscard      = iscsi_co_pdiscard,
     .bdrv_co_pwrite_zeroes = iscsi_co_pwrite_zeroes,
     .bdrv_co_readv         = iscsi_co_readv,
     .bdrv_co_writev_flags  = iscsi_co_writev_flags,
-- 
2.5.5