Introduce a singlethreaded workqueue to handle the I/O interrupts.
With the work added to this queue, we store the I/O results to the
io_region of the subchannel, then signal the userspace program to
handle the results.
Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_drv.c | 58 ++++++++++++++++++++++---------------
drivers/s390/cio/vfio_ccw_ops.c | 3 --
drivers/s390/cio/vfio_ccw_private.h | 7 ++---
3 files changed, 37 insertions(+), 31 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index b5971d3..3e0a40e 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -20,6 +20,8 @@
#include "css.h"
#include "vfio_ccw_private.h"
+struct workqueue_struct *vfio_ccw_work_q;
+
/*
* Helpers
*/
@@ -52,6 +54,7 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
spin_lock_irq(sch->lock);
private->completion = NULL;
+ flush_workqueue(vfio_ccw_work_q);
ret = cio_cancel_halt_clear(sch, &iretry);
};
@@ -63,18 +66,12 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch)
return ret;
}
-static int doing_io(struct vfio_ccw_private *private, u32 intparm)
-{
- return (private->intparm == intparm);
-}
-
static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
{
struct subchannel *sch;
union orb *orb;
int ccode;
__u8 lpm;
- u32 intparm;
sch = private->sch;
@@ -89,7 +86,7 @@ static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
* Initialize device status information
*/
sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
- break;
+ return 0;
case 1: /* Status pending */
case 2: /* Busy */
return -EBUSY;
@@ -109,15 +106,26 @@ static int vfio_ccw_sch_io_helper(struct vfio_ccw_private *private)
default:
return ccode;
}
+}
- intparm = (u32)(addr_t)sch;
- private->intparm = 0;
- wait_event(private->wait_q, doing_io(private, intparm));
+static void vfio_ccw_sch_io_todo(struct work_struct *work)
+{
+ struct vfio_ccw_private *private;
+ struct subchannel *sch;
+ struct irb *irb;
- if (scsw_is_solicited(&private->irb.scsw))
- cp_update_scsw(&private->cp, &private->irb.scsw);
+ private = container_of(work, struct vfio_ccw_private, io_work);
+ irb = &private->irb;
+ sch = private->sch;
- return 0;
+ if (scsw_is_solicited(&irb->scsw)) {
+ cp_update_scsw(&private->cp, &irb->scsw);
+ cp_free(&private->cp);
+ }
+ memcpy(private->io_region.irb_area, irb, sizeof(*irb));
+
+ if (private->io_trigger)
+ eventfd_signal(private->io_trigger, 1);
}
/* Deal with the ccw command request from the userspace. */
@@ -126,7 +134,6 @@ int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
struct mdev_device *mdev = private->mdev;
union orb *orb;
union scsw *scsw = &private->scsw;
- struct irb *irb = &private->irb;
struct ccw_io_region *io_region = &private->io_region;
int ret;
@@ -147,12 +154,8 @@ int vfio_ccw_sch_cmd_request(struct vfio_ccw_private *private)
/* Start channel program and wait for I/O interrupt. */
ret = vfio_ccw_sch_io_helper(private);
- if (!ret) {
- /* Get irb info and copy it to irb_area. */
- memcpy(io_region->irb_area, irb, sizeof(*irb));
- }
-
- cp_free(&private->cp);
+ if (!ret)
+ cp_free(&private->cp);
} else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) {
/* XXX: Handle halt. */
ret = -EOPNOTSUPP;
@@ -229,8 +232,8 @@ static void vfio_ccw_sch_irq(struct subchannel *sch)
irb = this_cpu_ptr(&cio_irb);
memcpy(&private->irb, irb, sizeof(*irb));
- private->intparm = (u32)(addr_t)sch;
- wake_up(&private->wait_q);
+
+ queue_work(vfio_ccw_work_q, &private->io_work);
if (private->completion)
complete(private->completion);
@@ -269,7 +272,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
if (ret)
goto out_rm_group;
- init_waitqueue_head(&private->wait_q);
+ INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
atomic_set(&private->avail, 1);
return 0;
@@ -367,10 +370,16 @@ static int __init vfio_ccw_sch_init(void)
{
int ret;
+ vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
+ if (!vfio_ccw_work_q)
+ return -ENOMEM;
+
isc_register(VFIO_CCW_ISC);
ret = css_driver_register(&vfio_ccw_sch_driver);
- if (ret)
+ if (ret) {
isc_unregister(VFIO_CCW_ISC);
+ destroy_workqueue(vfio_ccw_work_q);
+ }
return ret;
}
@@ -379,6 +388,7 @@ static void __exit vfio_ccw_sch_exit(void)
{
css_driver_unregister(&vfio_ccw_sch_driver);
isc_unregister(VFIO_CCW_ISC);
+ destroy_workqueue(vfio_ccw_work_q);
}
module_init(vfio_ccw_sch_init);
module_exit(vfio_ccw_sch_exit);
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 1294c53..d754d3d 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -202,9 +202,6 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
if (region->ret_code != 0)
return region->ret_code;
- if (private->io_trigger)
- eventfd_signal(private->io_trigger, 1);
-
return count;
}
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index dddab52..2503797 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -12,6 +12,7 @@
#include <linux/completion.h>
#include <linux/eventfd.h>
+#include <linux/workqueue.h>
#include <linux/vfio_ccw.h>
#include "css.h"
@@ -25,12 +26,11 @@
* @mdev: pointer to the mediated device
* @nb: notifier for vfio events
* @io_region: MMIO region to input/output I/O arguments/results
- * @wait_q: wait for interrupt
- * @intparm: record current interrupt parameter, used for wait interrupt
* @cp: channel program for the current I/O operation
* @irb: irb info received from interrupt
* @scsw: scsw info
* @io_trigger: eventfd ctx for signaling userspace I/O results
+ * @io_work: work for deferral process of I/O handling
*/
struct vfio_ccw_private {
struct subchannel *sch;
@@ -40,13 +40,12 @@ struct vfio_ccw_private {
struct notifier_block nb;
struct ccw_io_region io_region;
- wait_queue_head_t wait_q;
- u32 intparm;
struct channel_program cp;
struct irb irb;
union scsw scsw;
struct eventfd_ctx *io_trigger;
+ struct work_struct io_work;
} __aligned(8);
extern int vfio_ccw_mdev_reg(struct subchannel *sch);
--
2.8.4
