From f74e27bf0f07425aba6cb812aa7f5aa98bb68542 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Mon, 17 Oct 2016 14:13:58 +0200 Subject: [PATCH] 9pfs: only free completed request if not flushed If a PDU has a flush request pending, the current code calls pdu_free() twice: 1) pdu_complete()->pdu_free() with pdu->cancelled set, which does nothing 2) v9fs_flush()->pdu_free() with pdu->cancelled cleared, which moves the PDU back to the free list. This works but it complexifies the logic of pdu_free(). With this patch, pdu_complete() only calls pdu_free() if no flush request is pending, i.e. qemu_co_queue_next() returns false. Since pdu_free() is now supposed to be called with pdu->cancelled cleared, the check in pdu_free() is dropped and replaced by an assertion. Signed-off-by: Greg Kurz --- hw/9pfs/9p.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index df8aa726c9..f0dc2ce589 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -627,14 +627,10 @@ V9fsPDU *pdu_alloc(V9fsState *s) void pdu_free(V9fsPDU *pdu) { V9fsState *s = pdu->s; - /* - * Cancelled pdu are added back to the freelist - * by flush request . - */ - if (!pdu->cancelled) { - QLIST_REMOVE(pdu, next); - QLIST_INSERT_HEAD(&s->free_list, pdu, next); - } + + g_assert(!pdu->cancelled); + QLIST_REMOVE(pdu, next); + QLIST_INSERT_HEAD(&s->free_list, pdu, next); } /* @@ -679,9 +675,9 @@ static void coroutine_fn pdu_complete(V9fsPDU *pdu, ssize_t len) pdu_push_and_notify(pdu); /* Now wakeup anybody waiting in flush for this request */ - qemu_co_queue_next(&pdu->complete); - - pdu_free(pdu); + if (!qemu_co_queue_next(&pdu->complete)) { + pdu_free(pdu); + } } static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)