[Qemu-devel] [PATCH v4 2/3] ide: ignore retry_unit check for non-retry operation

["Denis V. Lunev" <den@openvz.org>]

From: Evgeny Yakovlev <eyakovlev@virtuozzo.com>

The following sequence of tests discovered a problem in IDE emulation:
1. Send DMA write to IDE device 0
2. Send CMD_FLUSH_CACHE to same IDE device which will be failed by block
layer using blkdebug script in tests/ide-test:test_retry_flush

When doing DMA request ide/core.c will set s->retry_unit to s->unit in
ide_start_dma. When dma completes ide_set_inactive sets retry_unit to -1.
After that ide_flush_cache runs and fails thanks to blkdebug.
ide_flush_cb calls ide_handle_rw_error which asserts that s->retry_unit
== s->unit. But s->retry_unit is still -1 after previous DMA completion
and flush does not use anything related to retry.

This patch restricts retry unit assertion only to ops that actually use
retry logic.

Signed-off-by: Evgeny Yakovlev <eyakovlev@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Fam Zheng <famz@redhat.com>
CC: John Snow <jsnow@redhat.com>
---
 hw/ide/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 029f6b9..17f884b 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -779,7 +779,8 @@ int ide_handle_rw_error(IDEState *s, int error, int op)
     BlockErrorAction action = blk_get_error_action(s->blk, is_read, error);
 
     if (action == BLOCK_ERROR_ACTION_STOP) {
-        assert(s->bus->retry_unit == s->unit);
+        assert(!(IS_IDE_RETRY_DMA(op) || IS_IDE_RETRY_PIO(op))
+                || s->bus->retry_unit == s->unit);
         s->bus->error_status = op;
     } else if (action == BLOCK_ERROR_ACTION_REPORT) {
         block_acct_failed(blk_get_stats(s->blk), &s->acct);
-- 
2.1.4