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When doing a dump, the scheduler is normally not running, so this

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changed worked to capture dumps for me. However, the test for
SCHEDULER_STOPPED() isn't right. We can also call the dump routine
from ddb, in which case the scheduler is still running. This leads to
an assertion panic that we're sleeping when we shouldn't. Instead, use
the proper test for dumping or not. This brings us in line with other
places that do special things while we're doing polled I/O like this.

Noticed by: pho@
Differential Revision: https://reviews.freebsd.org/D13531
This commit is contained in:
imp 2017-12-19 04:13:22 +00:00
parent cbf912d7da
commit 2a0d42981b
1 changed files with 14 additions and 7 deletions
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21
sys/cam/cam_periph.c
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@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h> #include <sys/malloc.h>
#include <sys/kernel.h> #include <sys/kernel.h>
#include <sys/bio.h> #include <sys/bio.h>
#include <sys/conf.h>
#include <sys/lock.h> #include <sys/lock.h>
#include <sys/mutex.h> #include <sys/mutex.h>
#include <sys/buf.h> #include <sys/buf.h>
@ -1158,7 +1159,7 @@ cam_periph_runccb(union ccb *ccb,
struct bintime *starttime; struct bintime *starttime;
struct bintime ltime; struct bintime ltime;
int error; int error;
bool sched_stopped; bool must_poll;
struct mtx *periph_mtx; struct mtx *periph_mtx;
struct cam_periph *periph; struct cam_periph *periph;
uint32_t timeout = 1; uint32_t timeout = 1;
@ -1182,7 +1183,13 @@ cam_periph_runccb(union ccb *ccb,
devstat_start_transaction(ds, starttime); devstat_start_transaction(ds, starttime);
} }
sched_stopped = SCHEDULER_STOPPED(); /*
* We must poll the I/O while we're dumping. The scheduler is normally
* stopped for dumping, except when we call doadump from ddb. While the
* scheduler is running in this case, we still need to poll the I/O to
* avoid sleeping waiting for the ccb to complete.
*/
must_poll = dumping;
ccb->ccb_h.cbfcnp = cam_periph_done; ccb->ccb_h.cbfcnp = cam_periph_done;
periph = xpt_path_periph(ccb->ccb_h.path); periph = xpt_path_periph(ccb->ccb_h.path);
periph_mtx = cam_periph_mtx(periph); periph_mtx = cam_periph_mtx(periph);
@ -1193,7 +1200,7 @@ cam_periph_runccb(union ccb *ccb,
* cam_periph_error can reschedule the ccb by calling xpt_action and returning * 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. * ERESTART, so we have to effect the polling in the do loop below.
*/ */
if (sched_stopped) { if (must_poll) {
mtx_unlock(periph_mtx); mtx_unlock(periph_mtx);
timeout = xpt_poll_setup(ccb); timeout = xpt_poll_setup(ccb);
} }
@ -1204,11 +1211,11 @@ cam_periph_runccb(union ccb *ccb,
} else { } else {
xpt_action(ccb); xpt_action(ccb);
do { do {
if (!sched_stopped) if (must_poll) {
cam_periph_ccbwait(ccb);
else {
xpt_pollwait(ccb, timeout); xpt_pollwait(ccb, timeout);
timeout = ccb->ccb_h.timeout * 10; timeout = ccb->ccb_h.timeout * 10;
} else {
cam_periph_ccbwait(ccb);
} }
if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP)
error = 0; error = 0;
@ -1220,7 +1227,7 @@ cam_periph_runccb(union ccb *ccb,
} while (error == ERESTART); } while (error == ERESTART);
} }
if (sched_stopped) if (must_poll)
mtx_lock(periph_mtx); mtx_lock(periph_mtx);
if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) { if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {