Commit f74e27bf authored by Greg Kurz's avatar Greg Kurz
Browse files

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: default avatarGreg Kurz <groug@kaod.org>
parent 6868a420

hw/9pfs/9p.c

+7 −11
Original line number Diff line number Diff line
@@ -627,15 +627,11 @@ 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) {



    g_assert(!pdu->cancelled);

    QLIST_REMOVE(pdu, next);

    QLIST_INSERT_HEAD(&s->free_list, pdu, next);

}

}



/*

 * We don't do error checking for pdu_marshal/unmarshal here
@@ -679,10 +675,10 @@ 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);



    if (!qemu_co_queue_next(&pdu->complete)) {

        pdu_free(pdu);

    }

}



static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)

{