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author | Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> | 2017-03-17 04:17:39 +0100 |
---|---|---|
committer | Cornelia Huck <cornelia.huck@de.ibm.com> | 2017-03-31 12:55:10 +0200 |
commit | e5f84dbaea59b4f712dac428c337528b70e1c533 (patch) | |
tree | f39d0e4e18b8a24b4da0b2d71f7a5c4aa70b3d18 /drivers | |
parent | 120e214e504fd6d3e33ec4b661193600b2faab95 (diff) | |
download | op-kernel-dev-e5f84dbaea59b4f712dac428c337528b70e1c533.zip op-kernel-dev-e5f84dbaea59b4f712dac428c337528b70e1c533.tar.gz |
vfio: ccw: return I/O results asynchronously
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@linux.vnet.ibm.com>
Message-Id: <20170317031743.40128-13-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/s390/cio/vfio_ccw_drv.c | 58 | ||||
-rw-r--r-- | drivers/s390/cio/vfio_ccw_ops.c | 3 | ||||
-rw-r--r-- | 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 @@ out_unlock: 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); |