Am 10.07.2013 um 15:49 hat Peter Lieven geschrieben: > Am 10.07.2013 11:41, schrieb Kevin Wolf: > > Am 27.06.2013 um 15:11 hat Peter Lieven geschrieben: > >> this patch adds a coroutine for .bdrv_co_is_allocated as well as > >> a generic framework that can be used to build coroutines in block/iscsi. > >> > >> Signed-off-by: Peter Lieven <p...@kamp.de> > >> --- > >> block/iscsi.c | 123 > >> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 123 insertions(+) > >> > >> diff --git a/block/iscsi.c b/block/iscsi.c > >> index 2e2455d..d31ee95 100644 > >> --- a/block/iscsi.c > >> +++ b/block/iscsi.c > >> @@ -58,6 +58,15 @@ typedef struct IscsiLun { > >> uint32_t max_unmap_bdc; > >> } IscsiLun; > >> > >> +typedef struct IscsiTask { > >> + int status; > >> + int complete; > >> + int retries; > >> + int do_retry; > >> + struct scsi_task *task; > >> + Coroutine *co; > >> +} IscsiTask; > >> + > >> typedef struct IscsiAIOCB { > >> BlockDriverAIOCB common; > >> QEMUIOVector *qiov; > >> @@ -113,6 +122,45 @@ iscsi_schedule_bh(IscsiAIOCB *acb) > >> qemu_bh_schedule(acb->bh); > >> } > >> > >> +static void > >> +iscsi_co_generic_cb(struct iscsi_context *iscsi, int status, > >> + void *command_data, void *opaque) > >> +{ > >> + struct IscsiTask *iTask = opaque; > >> + struct scsi_task *task = command_data; > >> + > >> + iTask->complete = 1; > >> + iTask->status = status; > >> + iTask->do_retry = 0; > >> + iTask->task = task; > >> + > >> + if (iTask->retries-- > 0 && status == SCSI_STATUS_CHECK_CONDITION > >> + && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) { > >> + iTask->do_retry = 1; > >> + goto out; > >> + } > >> + > >> + if (status != SCSI_STATUS_GOOD) { > >> + error_report("iSCSI: Failure. %s", iscsi_get_error(iscsi)); > >> + goto out; > >> + } > >> + > >> +out: > >> + if (iTask->status != SCSI_STATUS_GOOD) { > >> + scsi_free_scsi_task(iTask->task); > >> + iTask->task = NULL; > >> + } > >> + if (iTask->co) { > >> + qemu_coroutine_enter(iTask->co, NULL); > >> + } > >> +} > > In which context does this callback run? If this is from a separate > > thread, you may not do all of this (without even holding the QBL). You > > should probably use a BH to switch to the I/O thread. > good question. the callbacks can only be fired when iscsi_service() is > invoked. > this is currently done by registereing iscsi_process_read/write/flush via > qemu_aio_set_fd_handler(). > > so the callbacks are invoked in the aio context it seems. can this be right?
Yes, I took another look and I think it's fine. Kevin