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Add config_intrhook_oneshot(): schedule an intrhook function and unregister

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it automatically after it runs.

The config_intrhook mechanism allows a driver to stall the boot process
until device(s) required for booting are available, by not allowing system
inits to proceed until all intrhook functions have been unregistered.
Virtually all existing code simply unregisters from within the hook function
when it gets called.

This new function makes that common usage more convenient. Instead of
allocating and filling in a struct, passing it to a function that might (in
theory) fail, and checking the return code, now a driver can simply call
this cannot-fail routine, passing just the intrhook function and its arg.

Differential Revision:	https://reviews.freebsd.org/D11963
This commit is contained in:
Ian Lepore 2017-08-13 18:10:24 +00:00
parent 037331ddbd
commit 2db14f97de
4 changed files with 63 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
share/man/man9/Makefile
View File

@ -669,7 +669,8 @@ MLINKS+=condvar.9 cv_broadcast.9 \
condvar.9 cv_wait_unlock.9 \
condvar.9 cv_wmesg.9
MLINKS+=config_intrhook.9 config_intrhook_disestablish.9 \
config_intrhook.9 config_intrhook_establish.9
config_intrhook.9 config_intrhook_establish.9 \
config_intrhook.9 config_intrhook_oneshot.9
MLINKS+=contigmalloc.9 contigfree.9
MLINKS+=casuword.9 casueword.9 \
casuword.9 casueword32.9 \

21
share/man/man9/config_intrhook.9
View File

@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd September 24, 2006
.Dd August 10, 2017
.Dt CONFIG_INTRHOOK 9
.Os
.Sh NAME
@ -35,10 +35,13 @@
but before root is mounted
.Sh SYNOPSIS
.In sys/kernel.h
.Vt typedef void (*ich_func_t)(void *arg);
.Ft int
.Fn config_intrhook_establish "struct intr_config_hook *hook"
.Ft void
.Fn config_intrhook_disestablish "struct intr_config_hook *hook"
.Ft void
.Fn config_intrhook_oneshot "ich_func_t func" "void *arg"
.Sh DESCRIPTION
The
.Fn config_intrhook_establish
@ -51,6 +54,18 @@ The
.Fn config_intrhook_disestablish
function removes the entry from the hook queue.
.Pp
The
.Fn config_intrhook_oneshot
function schedules a function to be run as described for
.Fn config_intrhook_establish ;
the entry is automatically removed from the hook queue
after that function runs.
This is appropriate when additional device configuration must be done
after interrupts are enabled, but there is no need to stall the
boot process after that.
This function allocates memory using M_WAITOK; do not call this while
holding any non-sleepable locks.
.Pp
Before root is mounted, all the previously established hooks are
run.
The boot process is then stalled until all handlers remove their hook
@ -71,8 +86,8 @@ This structure is defined as follows:
.Bd -literal
struct intr_config_hook {
TAILQ_ENTRY(intr_config_hook) ich_links;/* Private */
void (*ich_func)(void *arg); /* function to call */
void *ich_arg; /* Argument to call */
ich_func_t ich_func; /* function to call */
void *ich_arg; /* Argument to call */
};
.Ed
.Pp

38
sys/kern/subr_autoconf.c
View File

@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/systm.h>
@ -62,6 +63,27 @@ MTX_SYSINIT(intr_config_hook, &intr_config_hook_lock, "intr config", MTX_DEF);
/* ARGSUSED */
static void run_interrupt_driven_config_hooks(void);
/*
* Private data and a shim function for implementing config_interhook_oneshot().
*/
struct oneshot_config_hook {
struct intr_config_hook
och_hook; /* Must be first */
ich_func_t och_func;
void *och_arg;
};
static void
config_intrhook_oneshot_func(void *arg)
{
struct oneshot_config_hook *ohook;
ohook = arg;
ohook->och_func(ohook->och_arg);
config_intrhook_disestablish(&ohook->och_hook);
free(ohook, M_DEVBUF);
}
/*
* If we wait too long for an interrupt-driven config hook to return, print
* a diagnostic.
@ -183,6 +205,22 @@ config_intrhook_establish(struct intr_config_hook *hook)
return (0);
}
/*
* Register a hook function that is automatically unregistered after it runs.
*/
void
config_intrhook_oneshot(ich_func_t func, void *arg)
{
struct oneshot_config_hook *ohook;
ohook = malloc(sizeof(*ohook), M_DEVBUF, M_WAITOK);
ohook->och_func = func;
ohook->och_arg = arg;
ohook->och_hook.ich_func = config_intrhook_oneshot_func;
ohook->och_hook.ich_arg = ohook;
config_intrhook_establish(&ohook->och_hook);
}
void
config_intrhook_disestablish(struct intr_config_hook *hook)
{

7
sys/sys/kernel.h
View File

@ -400,13 +400,16 @@ struct tunable_str {
#define TUNABLE_STR_FETCH(path, var, size) \
getenv_string((path), (var), (size))
typedef void (*ich_func_t)(void *_arg);
struct intr_config_hook {
TAILQ_ENTRY(intr_config_hook) ich_links;
void (*ich_func)(void *arg);
void *ich_arg;
ich_func_t ich_func;
void *ich_arg;
};
int config_intrhook_establish(struct intr_config_hook *hook);
void config_intrhook_disestablish(struct intr_config_hook *hook);
void config_intrhook_oneshot(ich_func_t _func, void *_arg);
#endif /* !_SYS_KERNEL_H_*/