On 06/22/2017 03:43 PM, Johannes Thumshirn wrote:
> In qla2xx_start_scsi_mq() and qla2xx_dif_start_scsi_mq() we grab the
> qpair->qp_lock but do access members of the qpair before having the lock.
> Re-order the locking sequence to have all read and write access to qpair
> members under the qpair->qp_lock.
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> ---
> drivers/scsi/qla2xxx/qla_iocb.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
> index 8404f17f3c6c..425ca1646a9a 100644
> --- a/drivers/scsi/qla2xxx/qla_iocb.c
> +++ b/drivers/scsi/qla2xxx/qla_iocb.c
> @@ -1770,10 +1770,6 @@ qla2xxx_start_scsi_mq(srb_t *sp)
> struct qla_hw_data *ha = vha->hw;
> struct qla_qpair *qpair = sp->qpair;
>
> - /* Setup qpair pointers */
> - rsp = qpair->rsp;
> - req = qpair->req;
> -
> /* So we know we haven't pci_map'ed anything yet */
> tot_dsds = 0;
>
> @@ -1788,6 +1784,10 @@ qla2xxx_start_scsi_mq(srb_t *sp)
> /* Acquire qpair specific lock */
> spin_lock_irqsave(&qpair->qp_lock, flags);
>
> + /* Setup qpair pointers */
> + rsp = qpair->rsp;
> + req = qpair->req;
> +
> /* Check for room in outstanding command list. */
> handle = req->current_outstanding_cmd;
> for (index = 1; index < req->num_outstanding_cmds; index++) {
> @@ -1924,24 +1924,33 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
>
> #define QDSS_GOT_Q_SPACE BIT_0
>
> + /* Acquire ring specific lock */
> + spin_lock_irqsave(&qpair->qp_lock, flags);
> +
> /* Check for host side state */
> if (!qpair->online) {
> cmd->result = DID_NO_CONNECT << 16;
> + spin_unlock_irqrestore(&qpair->qp_lock, flags);
> return QLA_INTERFACE_ERROR;
> }
>
> if (!qpair->difdix_supported &&
> scsi_get_prot_op(cmd) != SCSI_PROT_NORMAL) {
> cmd->result = DID_NO_CONNECT << 16;
> + spin_unlock_irqrestore(&qpair->qp_lock, flags);
> return QLA_INTERFACE_ERROR;
> }
>
> + spin_unlock_irqrestore(&qpair->qp_lock, flags);
> +
> /* Only process protection or >16 cdb in this routine */
> if (scsi_get_prot_op(cmd) == SCSI_PROT_NORMAL) {
> if (cmd->cmd_len <= 16)
> return qla2xxx_start_scsi_mq(sp);
> }
>
Not sure if that is required; at worst we're missing a device being
online; difdix support is probably not changing that often to be
warranted being protected with a lock here.
So I'd rather omit spinlocks here.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
