[PATCH 1/2] ide: Fix a rare hang during block draining

[Lukas Straub]

If the guest issues a discard during a block drain section, the
blk_aio_pdiscard() may not be processed, but queued instead.
And so the callback will never be called to issue the bh and decrease
the BB in-flight number again.
This causes a hang in the drain code, since it will wait forever for the
BB in-flight counter to decrease.

This reverts commit 7e5cdb34 "ide: Increment BB in-flight counter for TRIM BH"
to fix this hang. The bug fixed by that commit will be fixed differently
in the next commit.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 hw/ide/core.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index de48ff9f86..d172e70f1e 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -436,16 +436,12 @@ static const AIOCBInfo trim_aiocb_info = {
 static void ide_trim_bh_cb(void *opaque)
 {
     TrimAIOCB *iocb = opaque;
-    BlockBackend *blk = iocb->s->blk;
 
     iocb->common.cb(iocb->common.opaque, iocb->ret);
 
     qemu_bh_delete(iocb->bh);
     iocb->bh = NULL;
     qemu_aio_unref(iocb);
-
-    /* Paired with an increment in ide_issue_trim() */
-    blk_dec_in_flight(blk);
 }
 
 static void ide_issue_trim_cb(void *opaque, int ret)
@@ -516,9 +512,6 @@ BlockAIOCB *ide_issue_trim(
     IDEDevice *dev = s->unit ? s->bus->slave : s->bus->master;
     TrimAIOCB *iocb;
 
-    /* Paired with a decrement in ide_trim_bh_cb() */
-    blk_inc_in_flight(s->blk);
-
     iocb = blk_aio_get(&trim_aiocb_info, s->blk, cb, cb_opaque);
     iocb->s = s;
     iocb->bh = qemu_bh_new_guarded(ide_trim_bh_cb, iocb,
-- 
2.39.2

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