git: e52368365db3 - main - config_intrhook: provide config_intrhook_drain
Warner Losh
imp at FreeBSD.org
Thu Mar 11 16:45:12 UTC 2021
The branch main has been updated by imp:
URL: https://cgit.FreeBSD.org/src/commit/?id=e52368365db3c0a696b37bfc09d08b7093b41b57
commit e52368365db3c0a696b37bfc09d08b7093b41b57
Author: Warner Losh <imp at FreeBSD.org>
AuthorDate: 2021-03-11 15:42:09 +0000
Commit: Warner Losh <imp at FreeBSD.org>
CommitDate: 2021-03-11 16:45:10 +0000
config_intrhook: provide config_intrhook_drain
config_intrhook_drain will remove the hook from the list as
config_intrhook_disestablish does if the hook hasn't been called. If it has,
config_intrhook_drain will wait for the hook to be disestablished in the normal
course (or expedited, it's up to the driver to decide how and when
to call config_intrhook_disestablish).
This is intended for removable devices that use config_intrhook and might be
attached early in boot, but that may be removed before the kernel can call the
config_intrhook or before it ends. To prevent all races, the detach routine will
need to call config_intrhook_train.
Sponsored by: Netflix, Inc
Reviewed by: jhb, mav, gde (in D29006 for man page)
Differential Revision: https://reviews.freebsd.org/D29005
---
share/man/man9/Makefile | 1 +
share/man/man9/config_intrhook.9 | 21 ++++++++++++++++-
sys/kern/subr_autoconf.c | 50 +++++++++++++++++++++++++++++++++++++---
sys/sys/kernel.h | 6 ++++-
4 files changed, 73 insertions(+), 5 deletions(-)
diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index fb010231d710..52a5d373a417 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -859,6 +859,7 @@ 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_drain.9 \
config_intrhook.9 config_intrhook_establish.9 \
config_intrhook.9 config_intrhook_oneshot.9
MLINKS+=contigmalloc.9 contigmalloc_domainset.9 \
diff --git a/share/man/man9/config_intrhook.9 b/share/man/man9/config_intrhook.9
index 0414ad88218a..6892a089b00f 100644
--- a/share/man/man9/config_intrhook.9
+++ b/share/man/man9/config_intrhook.9
@@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd August 10, 2017
+.Dd March 8, 2021
.Dt CONFIG_INTRHOOK 9
.Os
.Sh NAME
@@ -40,6 +40,8 @@ but before root is mounted
.Fn config_intrhook_establish "struct intr_config_hook *hook"
.Ft void
.Fn config_intrhook_disestablish "struct intr_config_hook *hook"
+.Ft int
+.Fn config_intrhook_drain "struct intr_config_hook *hook"
.Ft void
.Fn config_intrhook_oneshot "ich_func_t func" "void *arg"
.Sh DESCRIPTION
@@ -55,6 +57,23 @@ The
function removes the entry from the hook queue.
.Pp
The
+.Fn config_intrhook_drain
+function removes the entry from the hook queue in a safe way.
+If the hook is not currently active it removes
+.Fa hook
+from the hook queue and returns
+.Vt ICHS_QUEUED .
+If the hook is active, it waits for the hook to complete before returning
+.Vt ICHS_RUNNING .
+If the hook has previously completed, it returns
+.Vt ICHS_DONE .
+Because a
+.Vt config_intrhook
+is undefined prior to
+.Fn config_intrhook_establish ,
+this function may only be called after that function has returned.
+.Pp
+The
.Fn config_intrhook_oneshot
function schedules a function to be run as described for
.Fn config_intrhook_establish ;
diff --git a/sys/kern/subr_autoconf.c b/sys/kern/subr_autoconf.c
index 063396a8e139..f6039e34e29f 100644
--- a/sys/kern/subr_autoconf.c
+++ b/sys/kern/subr_autoconf.c
@@ -138,6 +138,7 @@ run_interrupt_driven_config_hooks()
while (next_to_notify != NULL) {
hook_entry = next_to_notify;
next_to_notify = STAILQ_NEXT(hook_entry, ich_links);
+ hook_entry->ich_state = ICHS_RUNNING;
mtx_unlock(&intr_config_hook_lock);
(*hook_entry->ich_func)(hook_entry->ich_arg);
mtx_lock(&intr_config_hook_lock);
@@ -199,6 +200,7 @@ config_intrhook_establish(struct intr_config_hook *hook)
STAILQ_INSERT_TAIL(&intr_config_hook_list, hook, ich_links);
if (next_to_notify == NULL)
next_to_notify = hook;
+ hook->ich_state = ICHS_QUEUED;
mtx_unlock(&intr_config_hook_lock);
if (cold == 0)
/*
@@ -226,12 +228,11 @@ config_intrhook_oneshot(ich_func_t func, void *arg)
config_intrhook_establish(&ohook->och_hook);
}
-void
-config_intrhook_disestablish(struct intr_config_hook *hook)
+static void
+config_intrhook_disestablish_locked(struct intr_config_hook *hook)
{
struct intr_config_hook *hook_entry;
- mtx_lock(&intr_config_hook_lock);
STAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links)
if (hook_entry == hook)
break;
@@ -245,8 +246,51 @@ config_intrhook_disestablish(struct intr_config_hook *hook)
TSRELEASE("config hooks");
/* Wakeup anyone watching the list */
+ hook->ich_state = ICHS_DONE;
wakeup(&intr_config_hook_list);
+}
+
+void
+config_intrhook_disestablish(struct intr_config_hook *hook)
+{
+ mtx_lock(&intr_config_hook_lock);
+ config_intrhook_disestablish_locked(hook);
+ mtx_unlock(&intr_config_hook_lock);
+}
+
+int
+config_intrhook_drain(struct intr_config_hook *hook)
+{
+ mtx_lock(&intr_config_hook_lock);
+
+ /*
+ * The config hook has completed, so just return.
+ */
+ if (hook->ich_state == ICHS_DONE) {
+ mtx_unlock(&intr_config_hook_lock);
+ return (ICHS_DONE);
+ }
+
+ /*
+ * The config hook hasn't started running, just call disestablish.
+ */
+ if (hook->ich_state == ICHS_QUEUED) {
+ config_intrhook_disestablish_locked(hook);
+ mtx_unlock(&intr_config_hook_lock);
+ return (ICHS_QUEUED);
+ }
+
+ /*
+ * The config hook is running, so wait for it to complete and return.
+ */
+ while (hook->ich_state != ICHS_DONE) {
+ if (msleep(&intr_config_hook_list, &intr_config_hook_lock,
+ 0, "confhd", hz) == EWOULDBLOCK) {
+ // XXX do I whine?
+ }
+ }
mtx_unlock(&intr_config_hook_lock);
+ return (ICHS_RUNNING);
}
#ifdef DDB
diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h
index 89582ca5403d..e96eb52b52fd 100644
--- a/sys/sys/kernel.h
+++ b/sys/sys/kernel.h
@@ -467,13 +467,17 @@ typedef void (*ich_func_t)(void *_arg);
struct intr_config_hook {
STAILQ_ENTRY(intr_config_hook) ich_links;
- uintptr_t ich_padding;
+ uintptr_t ich_state;
+#define ICHS_QUEUED 0x1
+#define ICHS_RUNNING 0x2
+#define ICHS_DONE 0x3
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);
+int config_intrhook_drain(struct intr_config_hook *hook);
void config_intrhook_oneshot(ich_func_t _func, void *_arg);
#endif /* !_SYS_KERNEL_H_*/
More information about the dev-commits-src-main
mailing list