From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38863) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwviZ-00056b-09 for qemu-devel@nongnu.org; Wed, 10 Jul 2013 10:50:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UwviS-0000a8-Ds for qemu-devel@nongnu.org; Wed, 10 Jul 2013 10:50:06 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:35691 helo=mx01.kamp.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1UwviS-0000Zx-3D for qemu-devel@nongnu.org; Wed, 10 Jul 2013 10:50:00 -0400 Message-ID: <51DD7495.9040709@kamp.de> Date: Wed, 10 Jul 2013 16:49:57 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1372338695-411-1-git-send-email-pl@kamp.de> <1372338695-411-4-git-send-email-pl@kamp.de> <20130710094113.GE3898@dhcp-200-207.str.redhat.com> <51DD6685.6060406@kamp.de> <20130710144309.GT3898@dhcp-200-207.str.redhat.com> In-Reply-To: <20130710144309.GT3898@dhcp-200-207.str.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2 03/11] iscsi: add bdrv_co_is_allocated List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: pbonzini@redhat.com, ronniesahlberg@gmail.com, qemu-devel@nongnu.org, stefanha@redhat.com Am 10.07.2013 16:43, schrieb Kevin Wolf: > 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 >>>> --- >>>> 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. Would this still be true if all aio routines are replaced by coroutines? Peter