DRM could make great use of percpu-rwsems to track active users and wait
for them during hw hotplugging. Export symbols and allow using them in
runtime loadable modules.
Signed-off-by: David Herrmann <dh.herrm...@gmail.com>
---
lib/Makefile | 2 +-
lib/percpu-rwsem.c | 7 +++++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/lib/Makefile b/lib/Makefile
index f3bb2cb..c1572be 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -45,7 +45,7 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) +=
locking-selftest.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
-lib-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
+obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
diff --git a/lib/percpu-rwsem.c b/lib/percpu-rwsem.c
index 652a8ee..893586c 100644
--- a/lib/percpu-rwsem.c
+++ b/lib/percpu-rwsem.c
@@ -7,6 +7,7 @@
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/errno.h>
+#include <linux/export.h>
int __percpu_init_rwsem(struct percpu_rw_semaphore *brw,
const char *name, struct lock_class_key *rwsem_key)
@@ -22,12 +23,14 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *brw,
init_waitqueue_head(&brw->write_waitq);
return 0;
}
+EXPORT_SYMBOL(__percpu_init_rwsem);
void percpu_free_rwsem(struct percpu_rw_semaphore *brw)
{
free_percpu(brw->fast_read_ctr);
brw->fast_read_ctr = NULL; /* catch use after free bugs */
}
+EXPORT_SYMBOL(percpu_free_rwsem);
/*
* This is the fast-path for down_read/up_read, it only needs to ensure
@@ -87,6 +90,7 @@ void percpu_down_read(struct percpu_rw_semaphore *brw)
/* avoid up_read()->rwsem_release() */
__up_read(&brw->rw_sem);
}
+EXPORT_SYMBOL(percpu_down_read);
void percpu_up_read(struct percpu_rw_semaphore *brw)
{
@@ -99,6 +103,7 @@ void percpu_up_read(struct percpu_rw_semaphore *brw)
if (atomic_dec_and_test(&brw->slow_read_ctr))
wake_up_all(&brw->write_waitq);
}
+EXPORT_SYMBOL(percpu_up_read);
static int clear_fast_ctr(struct percpu_rw_semaphore *brw)
{
@@ -150,6 +155,7 @@ void percpu_down_write(struct percpu_rw_semaphore *brw)
/* wait for all readers to complete their percpu_up_read() */
wait_event(brw->write_waitq, !atomic_read(&brw->slow_read_ctr));
}
+EXPORT_SYMBOL(percpu_down_write);
void percpu_up_write(struct percpu_rw_semaphore *brw)
{
@@ -163,3 +169,4 @@ void percpu_up_write(struct percpu_rw_semaphore *brw)
/* the last writer unblocks update_fast_ctr() */
atomic_dec(&brw->write_ctr);
}
+EXPORT_SYMBOL(percpu_up_write);
--
1.8.4.1
--
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