Add locking to ppc and ppbus and mark the whole lot MPSAFE:

- To avoid having a bunch of locks that end up always getting acquired as
  a group, give each ppc(4) device a mutex which it shares with all the
  child devices including ppbus(4), lpt(4), plip(4), etc.  This mutex
  is then used for all the locking.
- Rework the interrupt handling stuff yet again.  Now ppbus drivers setup
  their interrupt handler during attach and tear it down during detach
  like most other drivers.  ppbus(4) only invokes the interrupt handler
  of the device that currently owns the bus (if any) when an interrupt
  occurs, however.  Also, interrupt handlers in general now accept their
  softc pointers as their argument rather than the device_t.  Another
  feature of the ppbus interrupt handlers is that they are called with
  the parent ppc device's lock already held.  This minimizes the number
  of lock operations during an interrupt.
- Mark plip(4), lpt(4), pcfclock(4), ppi(4), vpo(4) MPSAFE.
- lpbb(4) uses the ppc lock instead of Giant.
- Other plip(4) changes:
  - Add a mutex to protect the global tables in plip(4) and free them on
    module unload.
  - Add a detach routine.
  - Split out the init/stop code from the ioctl routine into separate
    functions.
- Other lpt(4) changes:
  - Use device_printf().
  - Use a dedicated callout for the lptout timer.
  - Allocate the I/O buffers at attach and detach rather than during
    open and close as this simplifies the locking at the cost of
    1024+32 bytes when the driver is attached.
- Other ppi(4) changes:
  - Use an sx lock to serialize open and close.
  - Remove unused HADBUS flag.
  - Add a detach routine.
  - Use a malloc'd buffer for each read and write to avoid races with
    concurrent read/write.
- Other pps(4) changes:
  - Use a callout rather than a callout handle with timeout().
  - Conform to the new ppbus requirements (regular mutex, non-filter
    interrupt handler).  pps(4) is probably going to have to become a
    standalone driver that doesn't use ppbus(4) to satisfy it's
    requirements for low latency as a result.
  - Use an sx lock to serialize open and close.
- Other vpo(4) changes:
  - Use the parent ppc device's lock to create the CAM sim instead of
    Giant.
- Other ppc(4) changes:
  - Fix ppc_isa's detach method to detach instead of calling attach.

Tested by:	  no one :-(

1 files changed, 17 insertions, 13 deletions

diff --git a/sys/dev/ppbus/vpo.c b/sys/dev/ppbus/vpo.c
index d0a8241..f63ff49 100644
--- a/sys/dev/ppbus/vpo.c
+++ b/sys/dev/ppbus/vpo.c
@@ -104,6 +104,7 @@ vpo_identify(driver_t *driver, device_t parent)
 static int
 vpo_probe(device_t dev)
 {
+	device_t ppbus = device_get_parent(dev);
 	struct vpo_data *vpo;
 	int error;
 
@@ -112,6 +113,7 @@ vpo_probe(device_t dev)
 
 	/* check ZIP before ZIP+ or imm_probe() will send controls to
 	 * the printer or whatelse connected to the port */
+	ppb_lock(ppbus);
 	if ((error = vpoio_probe(dev, &vpo->vpo_io)) == 0) {
 		vpo->vpo_isplus = 0;
 		device_set_desc(dev,
@@ -121,8 +123,10 @@ vpo_probe(device_t dev)
 		device_set_desc(dev,
 				"Iomega Matchmaker Parallel to SCSI interface");
 	} else {
+		ppb_unlock(ppbus);
 		return (error);
 	}
+	ppb_unlock(ppbus);
 
 	return (0);
 }
@@ -134,6 +138,8 @@ static int
 vpo_attach(device_t dev)
 {
 	struct vpo_data *vpo = DEVTOSOFTC(dev);
+	device_t ppbus = device_get_parent(dev);
+	struct ppb_data *ppb = device_get_softc(ppbus);	/* XXX: layering */
 	struct cam_devq *devq;
 	int error;
 
@@ -156,17 +162,20 @@ vpo_attach(device_t dev)
 		return (ENXIO);
 
 	vpo->sim = cam_sim_alloc(vpo_action, vpo_poll, "vpo", vpo,
-				 device_get_unit(dev), &Giant,
+				 device_get_unit(dev), ppb->ppc_lock,
 				 /*untagged*/1, /*tagged*/0, devq);
 	if (vpo->sim == NULL) {
 		cam_simq_free(devq);
 		return (ENXIO);
 	}
 
+	ppb_lock(ppbus);
 	if (xpt_bus_register(vpo->sim, dev, /*bus*/0) != CAM_SUCCESS) {
 		cam_sim_free(vpo->sim, /*free_devq*/TRUE);
+		ppb_unlock(ppbus);
 		return (ENXIO);
 	}
+	ppb_unlock(ppbus);
 
 	/* all went ok */
 
@@ -211,13 +220,10 @@ static void
 vpo_intr(struct vpo_data *vpo, struct ccb_scsiio *csio)
 {
 	int errno;	/* error in errno.h */
-	int s;
 #ifdef VP0_DEBUG
 	int i;
 #endif
 
-	s = splcam();
-
 	if (vpo->vpo_isplus) {
 		errno = imm_do_scsi(&vpo->vpo_io, VP0_INITIATOR,
 			csio->ccb_h.target_id,
@@ -246,7 +252,7 @@ vpo_intr(struct vpo_data *vpo, struct ccb_scsiio *csio)
 	if (errno) {
 		/* connection to ppbus interrupted */
 		csio->ccb_h.status = CAM_CMD_TIMEOUT;
-		goto error;
+		return;
 	}
 
 	/* if a timeout occured, no sense */
@@ -256,7 +262,7 @@ vpo_intr(struct vpo_data *vpo, struct ccb_scsiio *csio)
 				vpo->vpo_error);
 
 		csio->ccb_h.status = CAM_CMD_TIMEOUT;
-		goto error;
+		return;
 	}
 
 	/* check scsi status */
@@ -317,24 +323,22 @@ vpo_intr(struct vpo_data *vpo, struct ccb_scsiio *csio)
 		csio->ccb_h.status = CAM_SCSI_STATUS_ERROR;
 	   }
 
-	   goto error;
+	   return;
 	}
 
 	csio->resid = csio->dxfer_len - vpo->vpo_count;
 	csio->ccb_h.status = CAM_REQ_CMP;
-
-error:
-	splx(s);
-
-	return;
 }
 
 static void
 vpo_action(struct cam_sim *sim, union ccb *ccb)
 {
-
 	struct vpo_data *vpo = (struct vpo_data *)sim->softc;
+#ifdef INVARIANTS
+	device_t ppbus = device_get_parent(vpo->vpo_dev);
 
+	ppb_assert_locked(ppbus);
+#endif
 	switch (ccb->ccb_h.func_code) {
 	case XPT_SCSI_IO:
 	{