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author | imp <imp@FreeBSD.org> | 2009-08-25 06:25:59 +0000 |
---|---|---|
committer | imp <imp@FreeBSD.org> | 2009-08-25 06:25:59 +0000 |
commit | 649ad6d51f08e63f9c3680d76330f22f77410a01 (patch) | |
tree | 6060468c3c32db0466952bfc225ed35c3ea4b489 | |
parent | a0be63d7cbe8dfa27db870ab82ac49f1341f40f9 (diff) | |
download | FreeBSD-src-649ad6d51f08e63f9c3680d76330f22f77410a01.zip FreeBSD-src-649ad6d51f08e63f9c3680d76330f22f77410a01.tar.gz |
Rather than havnig enabled/disabled, implement a max queue depth.
While usually not an issue, this firewalls bugs in the code that may
run us out of memory.
Fix a memory exhaustion in the case where devctl was disabled, but the
link was bouncing. The check to queue was in the wrong place.
Implement a new sysctl hw.bus.devctl_queue to control the depth. Make
compatibility hacks for hw.bus.devctl_disable to ease transition.
Reviewed by: emaste@
Approved by: re@ (kib)
MFC after: asap
-rw-r--r-- | sys/kern/subr_bus.c | 75 |
1 files changed, 62 insertions, 13 deletions
diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c index 2964b8c..f202631 100644 --- a/sys/kern/subr_bus.c +++ b/sys/kern/subr_bus.c @@ -350,11 +350,18 @@ device_sysctl_fini(device_t dev) * tested since 3.4 or 2.2.8! */ +/* Deprecated way to adjust queue length */ static int sysctl_devctl_disable(SYSCTL_HANDLER_ARGS); -static int devctl_disable = 0; -TUNABLE_INT("hw.bus.devctl_disable", &devctl_disable); +/* XXX Need to support old-style tunable hw.bus.devctl_disable" */ SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_disable, CTLTYPE_INT | CTLFLAG_RW, NULL, - 0, sysctl_devctl_disable, "I", "devctl disable"); + 0, sysctl_devctl_disable, "I", "devctl disable -- deprecated"); + +#define DEVCTL_DEFAULT_QUEUE_LEN 1000 +static int sysctl_devctl_queue(SYSCTL_HANDLER_ARGS); +static int devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN; +TUNABLE_INT("hw.bus.devctl_queue", &devctl_queue_length); +SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_queue, CTLTYPE_INT | CTLFLAG_RW, NULL, + 0, sysctl_devctl_queue, "I", "devctl queue length"); static d_open_t devopen; static d_close_t devclose; @@ -385,6 +392,7 @@ static struct dev_softc { int inuse; int nonblock; + int queued; struct mtx mtx; struct cv cv; struct selinfo sel; @@ -423,7 +431,7 @@ devclose(struct cdev *dev, int fflag, int devtype, struct thread *td) mtx_lock(&devsoftc.mtx); cv_broadcast(&devsoftc.cv); mtx_unlock(&devsoftc.mtx); - + devsoftc.async_proc = NULL; return (0); } @@ -458,6 +466,7 @@ devread(struct cdev *dev, struct uio *uio, int ioflag) } n1 = TAILQ_FIRST(&devsoftc.devq); TAILQ_REMOVE(&devsoftc.devq, n1, dei_link); + devsoftc.queued--; mtx_unlock(&devsoftc.mtx); rv = uiomove(n1->dei_data, strlen(n1->dei_data), uio); free(n1->dei_data, M_BUS); @@ -531,21 +540,33 @@ devctl_process_running(void) void devctl_queue_data(char *data) { - struct dev_event_info *n1 = NULL; + struct dev_event_info *n1 = NULL, *n2 = NULL; struct proc *p; - /* - * Do not allow empty strings to be queued, as they - * cause devd to exit prematurely. - */ if (strlen(data) == 0) return; + if (devctl_queue_length == 0) + return; n1 = malloc(sizeof(*n1), M_BUS, M_NOWAIT); if (n1 == NULL) return; n1->dei_data = data; mtx_lock(&devsoftc.mtx); + if (devctl_queue_length == 0) { + free(n1->dei_data, M_BUS); + free(n1, M_BUS); + return; + } + /* Leave at least one spot in the queue... */ + while (devsoftc.queued > devctl_queue_length - 1) { + n2 = TAILQ_FIRST(&devsoftc.devq); + TAILQ_REMOVE(&devsoftc.devq, n2, dei_link); + free(n2->dei_data, M_BUS); + free(n2, M_BUS); + devsoftc.queued--; + } TAILQ_INSERT_TAIL(&devsoftc.devq, n1, dei_link); + devsoftc.queued++; cv_broadcast(&devsoftc.cv); mtx_unlock(&devsoftc.mtx); selwakeup(&devsoftc.sel); @@ -614,7 +635,7 @@ devaddq(const char *type, const char *what, device_t dev) char *pnp = NULL; const char *parstr; - if (devctl_disable) + if (!devctl_queue_length)/* Rare race, but lost races safely discard */ return; data = malloc(1024, M_BUS, M_NOWAIT); if (data == NULL) @@ -731,12 +752,11 @@ sysctl_devctl_disable(SYSCTL_HANDLER_ARGS) struct dev_event_info *n1; int dis, error; - dis = devctl_disable; + dis = devctl_queue_length == 0; error = sysctl_handle_int(oidp, &dis, 0, req); if (error || !req->newptr) return (error); mtx_lock(&devsoftc.mtx); - devctl_disable = dis; if (dis) { while (!TAILQ_EMPTY(&devsoftc.devq)) { n1 = TAILQ_FIRST(&devsoftc.devq); @@ -744,6 +764,35 @@ sysctl_devctl_disable(SYSCTL_HANDLER_ARGS) free(n1->dei_data, M_BUS); free(n1, M_BUS); } + devsoftc.queued = 0; + devctl_queue_length = 0; + } else { + devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN; + } + mtx_unlock(&devsoftc.mtx); + return (0); +} + +static int +sysctl_devctl_queue(SYSCTL_HANDLER_ARGS) +{ + struct dev_event_info *n1; + int q, error; + + q = devctl_queue_length; + error = sysctl_handle_int(oidp, &q, 0, req); + if (error || !req->newptr) + return (error); + if (q < 0) + return (EINVAL); + mtx_lock(&devsoftc.mtx); + devctl_queue_length = q; + while (devsoftc.queued > devctl_queue_length) { + n1 = TAILQ_FIRST(&devsoftc.devq); + TAILQ_REMOVE(&devsoftc.devq, n1, dei_link); + free(n1->dei_data, M_BUS); + free(n1, M_BUS); + devsoftc.queued--; } mtx_unlock(&devsoftc.mtx); return (0); @@ -886,7 +935,7 @@ devclass_find_internal(const char *classname, const char *parentname, if (create && !dc) { PDEBUG(("creating %s", classname)); dc = malloc(sizeof(struct devclass) + strlen(classname) + 1, - M_BUS, M_NOWAIT|M_ZERO); + M_BUS, M_NOWAIT | M_ZERO); if (!dc) return (NULL); dc->parent = NULL; |