From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44499) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vrs8P-000466-FS for qemu-devel@nongnu.org; Sat, 14 Dec 2013 11:32:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vrs8B-0005CN-FM for qemu-devel@nongnu.org; Sat, 14 Dec 2013 11:32:09 -0500 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:42738 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vrs8B-00058x-59 for qemu-devel@nongnu.org; Sat, 14 Dec 2013 11:31:55 -0500 From: Peter Lieven Date: Sat, 14 Dec 2013 17:31:40 +0100 Message-Id: <1387038700-9264-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH] block/iscsi: use a bh to schedule co reentrance List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, Peter Lieven , qemu-stable@nongnu.org, ronniesahlberg@gmail.com, anthony@codemonkey.ws, pbonzini@redhat.com this fixes a potential segfault and performance regression. If the coroutine is reentered directly in the iscsi_co_generic_cb iscsi_process_{read,write} are interrupted and reentered any time later. One the one hand this could happen after an iscsi_close where the iscsi context is already gone (segfault). On the other hand this limits the number of processed callbacks in each aio_dispatch to one (potential performance regression). Cc: qemu-stable@nongnu.org Signed-off-by: Peter Lieven --- block/iscsi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/block/iscsi.c b/block/iscsi.c index fa69408..b0e6eea 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -68,6 +68,7 @@ typedef struct IscsiTask { int do_retry; struct scsi_task *task; Coroutine *co; + QEMUBH *bh; } IscsiTask; typedef struct IscsiAIOCB { @@ -123,6 +124,13 @@ iscsi_schedule_bh(IscsiAIOCB *acb) qemu_bh_schedule(acb->bh); } +static void iscsi_co_generic_bh_cb(void *opaque) +{ + struct IscsiTask *iTask = opaque; + qemu_bh_delete(iTask->bh); + qemu_coroutine_enter(iTask->co, NULL); +} + static void iscsi_co_generic_cb(struct iscsi_context *iscsi, int status, void *command_data, void *opaque) @@ -147,7 +155,8 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status, out: if (iTask->co) { - qemu_coroutine_enter(iTask->co, NULL); + iTask->bh = qemu_bh_new(iscsi_co_generic_bh_cb, iTask); + qemu_bh_schedule(iTask->bh); } } -- 1.7.9.5