svn commit: r326643 - head/sys/cam
Warner Losh
imp at FreeBSD.org
Wed Dec 6 23:05:08 UTC 2017
Author: imp
Date: Wed Dec 6 23:05:07 2017
New Revision: 326643
URL: https://svnweb.freebsd.org/changeset/base/326643
Log:
Make cam_periph_runccb be safe to call when we can only do polling.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D13388
Modified:
head/sys/cam/cam_periph.c
head/sys/cam/cam_xpt.c
head/sys/cam/cam_xpt.h
Modified: head/sys/cam/cam_periph.c
==============================================================================
--- head/sys/cam/cam_periph.c Wed Dec 6 23:03:34 2017 (r326642)
+++ head/sys/cam/cam_periph.c Wed Dec 6 23:05:07 2017 (r326643)
@@ -1160,7 +1160,11 @@ cam_periph_runccb(union ccb *ccb,
struct bintime *starttime;
struct bintime ltime;
int error;
-
+ bool sched_stopped;
+ struct mtx *periph_mtx;
+ struct cam_periph *periph;
+ uint32_t timeout = 1;
+
starttime = NULL;
xpt_path_assert(ccb->ccb_h.path, MA_OWNED);
KASSERT((ccb->ccb_h.flags & CAM_UNLOCKED) == 0,
@@ -1180,21 +1184,47 @@ cam_periph_runccb(union ccb *ccb,
devstat_start_transaction(ds, starttime);
}
+ sched_stopped = SCHEDULER_STOPPED();
ccb->ccb_h.cbfcnp = cam_periph_done;
- xpt_action(ccb);
-
- do {
- cam_periph_ccbwait(ccb);
- if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP)
- error = 0;
- else if (error_routine != NULL) {
- ccb->ccb_h.cbfcnp = cam_periph_done;
- error = (*error_routine)(ccb, camflags, sense_flags);
- } else
- error = 0;
+ periph = xpt_path_periph(ccb->ccb_h.path);
+ periph_mtx = cam_periph_mtx(periph);
- } while (error == ERESTART);
-
+ /*
+ * If we're polling, then we need to ensure that we have ample resources
+ * in the periph. We also need to drop the periph lock while we're polling.
+ * cam_periph_error can reschedule the ccb by calling xpt_action and returning
+ * ERESTART, so we have to effect the polling in the do loop below.
+ */
+ if (sched_stopped) {
+ mtx_unlock(periph_mtx);
+ timeout = xpt_poll_setup(ccb);
+ }
+
+ if (timeout == 0) {
+ ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
+ error = EBUSY;
+ } else {
+ xpt_action(ccb);
+ do {
+ if (!sched_stopped)
+ cam_periph_ccbwait(ccb);
+ else {
+ xpt_pollwait(ccb, timeout);
+ timeout = ccb->ccb_h.timeout * 10;
+ }
+ if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP)
+ error = 0;
+ else if (error_routine != NULL) {
+ ccb->ccb_h.cbfcnp = cam_periph_done;
+ error = (*error_routine)(ccb, camflags, sense_flags);
+ } else
+ error = 0;
+ } while (error == ERESTART);
+ }
+
+ if (sched_stopped)
+ mtx_lock(periph_mtx);
+
if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
cam_release_devq(ccb->ccb_h.path,
/* relsim_flags */0,
Modified: head/sys/cam/cam_xpt.c
==============================================================================
--- head/sys/cam/cam_xpt.c Wed Dec 6 23:03:34 2017 (r326642)
+++ head/sys/cam/cam_xpt.c Wed Dec 6 23:05:07 2017 (r326643)
@@ -3204,8 +3204,8 @@ call_sim:
start_ccb->ccb_h.status));
}
-void
-xpt_polled_action(union ccb *start_ccb)
+uint32_t
+xpt_poll_setup(union ccb *start_ccb)
{
u_int32_t timeout;
struct cam_sim *sim;
@@ -3219,8 +3219,6 @@ xpt_polled_action(union ccb *start_ccb)
mtx = sim->mtx;
dev = start_ccb->ccb_h.path->device;
- mtx_unlock(&dev->device_mtx);
-
/*
* Steal an opening so that no other queued requests
* can get it before us while we simulate interrupts.
@@ -3242,29 +3240,57 @@ xpt_polled_action(union ccb *start_ccb)
dev->ccbq.dev_openings++;
mtx_unlock(&devq->send_mtx);
- if (timeout != 0) {
+ return (timeout);
+}
+
+void
+xpt_pollwait(union ccb *start_ccb, uint32_t timeout)
+{
+ struct cam_sim *sim;
+ struct mtx *mtx;
+
+ sim = start_ccb->ccb_h.path->bus->sim;
+ mtx = sim->mtx;
+
+ while (--timeout > 0) {
+ if (mtx)
+ mtx_lock(mtx);
+ (*(sim->sim_poll))(sim);
+ if (mtx)
+ mtx_unlock(mtx);
+ camisr_runqueue();
+ if ((start_ccb->ccb_h.status & CAM_STATUS_MASK)
+ != CAM_REQ_INPROG)
+ break;
+ DELAY(100);
+ }
+
+ if (timeout == 0) {
+ /*
+ * XXX Is it worth adding a sim_timeout entry
+ * point so we can attempt recovery? If
+ * this is only used for dumps, I don't think
+ * it is.
+ */
+ start_ccb->ccb_h.status = CAM_CMD_TIMEOUT;
+ }
+}
+
+void
+xpt_polled_action(union ccb *start_ccb)
+{
+ uint32_t timeout;
+ struct cam_ed *dev;
+
+ timeout = start_ccb->ccb_h.timeout * 10;
+ dev = start_ccb->ccb_h.path->device;
+
+ mtx_unlock(&dev->device_mtx);
+
+ timeout = xpt_poll_setup(start_ccb);
+ if (timeout > 0) {
xpt_action(start_ccb);
- while(--timeout > 0) {
- if (mtx)
- mtx_lock(mtx);
- (*(sim->sim_poll))(sim);
- if (mtx)
- mtx_unlock(mtx);
- camisr_runqueue();
- if ((start_ccb->ccb_h.status & CAM_STATUS_MASK)
- != CAM_REQ_INPROG)
- break;
- DELAY(100);
- }
- if (timeout == 0) {
- /*
- * XXX Is it worth adding a sim_timeout entry
- * point so we can attempt recovery? If
- * this is only used for dumps, I don't think
- * it is.
- */
- start_ccb->ccb_h.status = CAM_CMD_TIMEOUT;
- }
+ xpt_pollwait(start_ccb, timeout);
} else {
start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
}
@@ -3305,6 +3331,7 @@ xpt_schedule_dev(struct camq *queue, cam_pinfo *pinfo,
u_int32_t old_priority;
CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_schedule_dev\n"));
+
old_priority = pinfo->priority;
Modified: head/sys/cam/cam_xpt.h
==============================================================================
--- head/sys/cam/cam_xpt.h Wed Dec 6 23:03:34 2017 (r326642)
+++ head/sys/cam/cam_xpt.h Wed Dec 6 23:05:07 2017 (r326643)
@@ -144,6 +144,8 @@ void xpt_copy_path(struct cam_path *new_path,
void xpt_release_path(struct cam_path *path);
const char * xpt_action_name(uint32_t action);
+void xpt_pollwait(union ccb *start_ccb, uint32_t timeout);
+uint32_t xpt_poll_setup(union ccb *start_ccb);
#endif /* _KERNEL */
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