diff options
author | ken <ken@FreeBSD.org> | 2003-09-03 04:46:28 +0000 |
---|---|---|
committer | ken <ken@FreeBSD.org> | 2003-09-03 04:46:28 +0000 |
commit | 03d0445c1692534218893d0f76a5232a12769935 (patch) | |
tree | 54485ba0616eea8f013a6221f95c3b93a70168ce /sys | |
parent | 96db6adb01216f8a587311123b15f9ae3c246431 (diff) | |
download | FreeBSD-src-03d0445c1692534218893d0f76a5232a12769935.zip FreeBSD-src-03d0445c1692534218893d0f76a5232a12769935.tar.gz |
Move dynamic sysctl(8) variable creation for the cd(4) and da(4) drivers
out of cdregister() and daregister(), which are run from interrupt context.
The sysctl code does blocking mallocs (M_WAITOK), which causes problems
if malloc(9) actually needs to sleep.
The eventual fix for this issue will involve moving the CAM probe process
inside a kernel thread. For now, though, I have fixed the issue by moving
dynamic sysctl variable creation for these two drivers to a task queue
running in a kernel thread.
The existing task queues (taskqueue_swi and taskqueue_swi_giant) run in
software interrupt handlers, which wouldn't fix the problem at hand. So I
have created a new task queue, taskqueue_thread, that runs inside a kernel
thread. (It also runs outside of Giant -- clients must explicitly acquire
and release Giant in their taskqueue functions.)
scsi_cd.c: Remove sysctl variable creation code from cdregister(), and
move it to a new function, cdsysctlinit(). Queue
cdsysctlinit() to the taskqueue_thread taskqueue once we
have fully registered the cd(4) driver instance.
scsi_da.c: Remove sysctl variable creation code from daregister(), and
move it to move it to a new function, dasysctlinit().
Queue dasysctlinit() to the taskqueue_thread taskqueue once
we have fully registered the da(4) instance.
taskqueue.h: Declare the new taskqueue_thread taskqueue, update some
comments.
subr_taskqueue.c:
Create the new kernel thread taskqueue. This taskqueue
runs outside of Giant, so any functions queued to it would
need to explicitly acquire/release Giant if they need it.
cd.4: Update the cd(4) man page to talk about the minimum command
size sysctl/loader tunable. Also note that the changer
variables are available as loader tunables as well.
da.4: Update the da(4) man page to cover the retry_count,
default_timeout and minimum_cmd_size sysctl variables/loader
tunables. Remove references to /dev/r???, they aren't used
any longer.
cd.9: Update the cd(9) man page to describe the CD_Q_10_BYTE_ONLY
quirk.
taskqueue.9: Update the taskqueue(9) man page to describe the new thread
task queue, and the taskqueue_swi_giant queue.
MFC after: 3 days
Diffstat (limited to 'sys')
-rw-r--r-- | sys/cam/scsi/scsi_cd.c | 67 | ||||
-rw-r--r-- | sys/cam/scsi/scsi_da.c | 69 | ||||
-rw-r--r-- | sys/kern/subr_taskqueue.c | 32 | ||||
-rw-r--r-- | sys/sys/taskqueue.h | 11 |
4 files changed, 134 insertions, 45 deletions
diff --git a/sys/cam/scsi/scsi_cd.c b/sys/cam/scsi/scsi_cd.c index a887243..39c2562 100644 --- a/sys/cam/scsi/scsi_cd.c +++ b/sys/cam/scsi/scsi_cd.c @@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$"); #include <sys/dvdio.h> #include <sys/devicestat.h> #include <sys/sysctl.h> +#include <sys/taskqueue.h> #include <cam/cam.h> #include <cam/cam_ccb.h> @@ -154,6 +155,7 @@ struct cd_softc { eventhandler_tag clonetag; int minimum_command_size; int outstanding_cmds; + struct task sysctl_task; struct sysctl_ctx_list sysctl_ctx; struct sysctl_oid *sysctl_tree; STAILQ_HEAD(, cd_mode_params) mode_queue; @@ -598,6 +600,43 @@ cdasync(void *callback_arg, u_int32_t code, } } +static void +cdsysctlinit(void *context, int pending) +{ + struct cam_periph *periph; + struct cd_softc *softc; + char tmpstr[80], tmpstr2[80]; + + periph = (struct cam_periph *)context; + softc = (struct cd_softc *)periph->softc; + + snprintf(tmpstr, sizeof(tmpstr), "CAM CD unit %d", periph->unit_number); + snprintf(tmpstr2, sizeof(tmpstr2), "%d", periph->unit_number); + + mtx_lock(&Giant); + + sysctl_ctx_init(&softc->sysctl_ctx); + softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx, + SYSCTL_STATIC_CHILDREN(_kern_cam_cd), OID_AUTO, + tmpstr2, CTLFLAG_RD, 0, tmpstr); + + if (softc->sysctl_tree == NULL) { + printf("cdsysctlinit: unable to allocate sysctl tree\n"); + return; + } + + /* + * Now register the sysctl handler, so the user can the value on + * the fly. + */ + SYSCTL_ADD_PROC(&softc->sysctl_ctx,SYSCTL_CHILDREN(softc->sysctl_tree), + OID_AUTO, "minimum_cmd_size", CTLTYPE_INT | CTLFLAG_RW, + &softc->minimum_command_size, 0, cdcmdsizesysctl, "I", + "Minimum CDB size"); + + mtx_unlock(&Giant); +} + /* * We have a handler function for this so we can check the values when the * user sets them, instead of every time we look at them. @@ -642,7 +681,7 @@ cdregister(struct cam_periph *periph, void *arg) struct ccb_setasync csa; struct ccb_pathinq cpi; struct ccb_getdev *cgd; - char tmpstr[80], tmpstr2[80]; + char tmpstr[80]; caddr_t match; cgd = (struct ccb_getdev *)arg; @@ -696,17 +735,7 @@ cdregister(struct cam_periph *periph, void *arg) if (cpi.ccb_h.status == CAM_REQ_CMP && (cpi.hba_misc & PIM_NO_6_BYTE)) softc->quirks |= CD_Q_10_BYTE_ONLY; - snprintf(tmpstr, sizeof(tmpstr), "CAM CD unit %d", periph->unit_number); - snprintf(tmpstr2, sizeof(tmpstr2), "%d", periph->unit_number); - sysctl_ctx_init(&softc->sysctl_ctx); - softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx, - SYSCTL_STATIC_CHILDREN(_kern_cam_cd), OID_AUTO, - tmpstr2, CTLFLAG_RD, 0, tmpstr); - if (softc->sysctl_tree == NULL) { - printf("cdregister: unable to allocate sysctl tree\n"); - free(softc, M_DEVBUF); - return (CAM_REQ_CMP_ERR); - } + TASK_INIT(&softc->sysctl_task, 0, cdsysctlinit, periph); /* The default is 6 byte commands, unless quirked otherwise */ if (softc->quirks & CD_Q_10_BYTE_ONLY) @@ -728,15 +757,6 @@ cdregister(struct cam_periph *periph, void *arg) softc->minimum_command_size = 10; /* - * Now register the sysctl handler, so the user can the value on - * the fly. - */ - SYSCTL_ADD_PROC(&softc->sysctl_ctx,SYSCTL_CHILDREN(softc->sysctl_tree), - OID_AUTO, "minimum_cmd_size", CTLTYPE_INT | CTLFLAG_RW, - &softc->minimum_command_size, 0, cdcmdsizesysctl, "I", - "Minimum CDB size"); - - /* * We need to register the statistics structure for this device, * but we don't have the blocksize yet for it. So, we register * the structure and indicate that we don't have the blocksize @@ -1847,6 +1867,11 @@ cddone(struct cam_periph *periph, union ccb *done_ccb) xpt_announce_periph(periph, announce_buf); if (softc->flags & CD_FLAG_CHANGER) cdchangerschedule(softc); + /* + * Create our sysctl variables, now that we know + * we have successfully attached. + */ + taskqueue_enqueue(taskqueue_thread,&softc->sysctl_task); } softc->state = CD_STATE_NORMAL; /* diff --git a/sys/cam/scsi/scsi_da.c b/sys/cam/scsi/scsi_da.c index e2edbcf..ce2bfff 100644 --- a/sys/cam/scsi/scsi_da.c +++ b/sys/cam/scsi/scsi_da.c @@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$"); #include <sys/eventhandler.h> #include <sys/malloc.h> #include <sys/cons.h> +#include <sys/taskqueue.h> #include <machine/md_var.h> @@ -133,6 +134,7 @@ struct da_softc { struct disk_params params; struct disk disk; union ccb saved_ccb; + struct task sysctl_task; struct sysctl_ctx_list sysctl_ctx; struct sysctl_oid *sysctl_tree; }; @@ -388,6 +390,7 @@ static dumper_t dadump; static periph_init_t dainit; static void daasync(void *callback_arg, u_int32_t code, struct cam_path *path, void *arg); +static void dasysctlinit(void *context, int pending); static int dacmdsizesysctl(SYSCTL_HANDLER_ARGS); static periph_ctor_t daregister; static periph_dtor_t dacleanup; @@ -915,6 +918,41 @@ daasync(void *callback_arg, u_int32_t code, } } +static void +dasysctlinit(void *context, int pending) +{ + struct cam_periph *periph; + struct da_softc *softc; + char tmpstr[80], tmpstr2[80]; + + periph = (struct cam_periph *)context; + softc = (struct da_softc *)periph->softc; + + snprintf(tmpstr, sizeof(tmpstr), "CAM DA unit %d", periph->unit_number); + snprintf(tmpstr2, sizeof(tmpstr2), "%d", periph->unit_number); + + mtx_lock(&Giant); + sysctl_ctx_init(&softc->sysctl_ctx); + softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx, + SYSCTL_STATIC_CHILDREN(_kern_cam_da), OID_AUTO, tmpstr2, + CTLFLAG_RD, 0, tmpstr); + if (softc->sysctl_tree == NULL) { + printf("dasysctlinit: unable to allocate sysctl tree\n"); + return; + } + + /* + * Now register the sysctl handler, so the user can the value on + * the fly. + */ + SYSCTL_ADD_PROC(&softc->sysctl_ctx,SYSCTL_CHILDREN(softc->sysctl_tree), + OID_AUTO, "minimum_cmd_size", CTLTYPE_INT | CTLFLAG_RW, + &softc->minimum_cmd_size, 0, dacmdsizesysctl, "I", + "Minimum CDB size"); + + mtx_unlock(&Giant); +} + static int dacmdsizesysctl(SYSCTL_HANDLER_ARGS) { @@ -955,7 +993,7 @@ daregister(struct cam_periph *periph, void *arg) struct ccb_setasync csa; struct ccb_pathinq cpi; struct ccb_getdev *cgd; - char tmpstr[80], tmpstr2[80]; + char tmpstr[80]; caddr_t match; cgd = (struct ccb_getdev *)arg; @@ -1008,17 +1046,7 @@ daregister(struct cam_periph *periph, void *arg) if (cpi.ccb_h.status == CAM_REQ_CMP && (cpi.hba_misc & PIM_NO_6_BYTE)) softc->quirks |= DA_Q_NO_6_BYTE; - snprintf(tmpstr, sizeof(tmpstr), "CAM DA unit %d", periph->unit_number); - snprintf(tmpstr2, sizeof(tmpstr2), "%d", periph->unit_number); - sysctl_ctx_init(&softc->sysctl_ctx); - softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx, - SYSCTL_STATIC_CHILDREN(_kern_cam_da), OID_AUTO, tmpstr2, - CTLFLAG_RD, 0, tmpstr); - if (softc->sysctl_tree == NULL) { - printf("daregister: unable to allocate sysctl tree\n"); - free(softc, M_DEVBUF); - return (CAM_REQ_CMP_ERR); - } + TASK_INIT(&softc->sysctl_task, 0, dasysctlinit, periph); /* * RBC devices don't have to support READ(6), only READ(10). @@ -1050,15 +1078,6 @@ daregister(struct cam_periph *periph, void *arg) softc->minimum_cmd_size = 16; /* - * Now register the sysctl handler, so the user can the value on - * the fly. - */ - SYSCTL_ADD_PROC(&softc->sysctl_ctx,SYSCTL_CHILDREN(softc->sysctl_tree), - OID_AUTO, "minimum_cmd_size", CTLTYPE_INT | CTLFLAG_RW, - &softc->minimum_cmd_size, 0, dacmdsizesysctl, "I", - "Minimum CDB size"); - - /* * Block our timeout handler while we * add this softc to the dev list. */ @@ -1539,8 +1558,14 @@ dadone(struct cam_periph *periph, union ccb *done_ccb) } } free(csio->data_ptr, M_TEMP); - if (announce_buf[0] != '\0') + if (announce_buf[0] != '\0') { xpt_announce_periph(periph, announce_buf); + /* + * Create our sysctl variables, now that we know + * we have successfully attached. + */ + taskqueue_enqueue(taskqueue_thread,&softc->sysctl_task); + } softc->state = DA_STATE_NORMAL; /* * Since our peripheral may be invalidated by an error diff --git a/sys/kern/subr_taskqueue.c b/sys/kern/subr_taskqueue.c index fa32be6..bb1f1b6 100644 --- a/sys/kern/subr_taskqueue.c +++ b/sys/kern/subr_taskqueue.c @@ -36,6 +36,8 @@ __FBSDID("$FreeBSD$"); #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/taskqueue.h> +#include <sys/kthread.h> +#include <sys/unistd.h> static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); @@ -44,6 +46,7 @@ static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; static void *taskqueue_ih; static void *taskqueue_giant_ih; static struct mtx taskqueue_queues_mutex; +static struct proc *taskqueue_thread_proc; struct taskqueue { STAILQ_ENTRY(taskqueue) tq_link; @@ -233,6 +236,31 @@ taskqueue_swi_giant_run(void *dummy) taskqueue_run(taskqueue_swi_giant); } +static void +taskqueue_kthread(void *arg) +{ + struct mtx kthread_mutex; + + bzero(&kthread_mutex, sizeof(kthread_mutex)); + + mtx_init(&kthread_mutex, "taskqueue kthread", NULL, MTX_DEF); + + mtx_lock(&kthread_mutex); + + for (;;) { + mtx_unlock(&kthread_mutex); + taskqueue_run(taskqueue_thread); + mtx_lock(&kthread_mutex); + msleep(&taskqueue_thread, &kthread_mutex, PWAIT, "tqthr", 0); + } +} + +static void +taskqueue_thread_enqueue(void *context) +{ + wakeup(&taskqueue_thread); +} + TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, INTR_MPSAFE, &taskqueue_ih)); @@ -240,3 +268,7 @@ TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run, NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); + +TASKQUEUE_DEFINE(thread, taskqueue_thread_enqueue, 0, + kthread_create(taskqueue_kthread, NULL, + &taskqueue_thread_proc, RFNOWAIT, 0, "taskqueue")); diff --git a/sys/sys/taskqueue.h b/sys/sys/taskqueue.h index 953bc28..d0cac11 100644 --- a/sys/sys/taskqueue.h +++ b/sys/sys/taskqueue.h @@ -107,10 +107,17 @@ SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND, \ struct __hack /* - * This queue is serviced by a software interrupt handler. To enqueue - * a task, call taskqueue_enqueue(taskqueue_swi, &task). + * These queues are serviced by software interrupt handlers. To enqueue + * a task, call taskqueue_enqueue(taskqueue_swi, &task) or + * taskqueue_enqueue(taskqueue_swi_giant, &task). */ TASKQUEUE_DECLARE(swi_giant); TASKQUEUE_DECLARE(swi); +/* + * This queue is serviced by a kernel thread. To enqueue a task, call + * taskqueue_enqueue(taskqueue_thread, &task). + */ +TASKQUEUE_DECLARE(thread); + #endif /* !_SYS_TASKQUEUE_H_ */ |