From 8b9dfe9098d91e06a3dd6376624307fe5fa13be8 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Sat, 14 Dec 2013 17:31:40 +0100 Subject: [PATCH] block/iscsi: use a bh to schedule co reentrance 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 Signed-off-by: Paolo Bonzini --- block/iscsi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/block/iscsi.c b/block/iscsi.c index fa69408df9..b0e6eea199 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); } } -- 2.11.4.GIT