dm vdo uds-threads: push 'barrier' down to sparse-cache

The sparse-cache is the only user of the 'barrier' data structure,
so just move it private to it.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

drivers/md/dm-vdo/sparse-cache.c

@@ -6,6 +6,7 @@
 #include "sparse-cache.h"
 
 #include <linux/cache.h>
+#include <linux/delay.h>
 #include <linux/dm-bufio.h>
 
 #include "chapter-index.h"
@@ -14,7 +15,6 @@
 #include "logger.h"
 #include "memory-alloc.h"
 #include "permassert.h"
-#include "uds-threads.h"
 
 /*
  * Since the cache is small, it is implemented as a simple array of cache entries. Searching for a
@@ -141,6 +141,17 @@ struct search_list {
 	struct cached_chapter_index *entries[];
 };
 
+struct barrier {
+	/* Lock for this barrier object */
+	struct semaphore lock;
+	/* Semaphore for threads waiting at this barrier */
+	struct semaphore wait;
+	/* Number of threads which have arrived */
+	int arrived;
+	/* Total number of threads using this barrier */
+	int thread_count;
+};
+
 struct sparse_cache {
 	const struct index_geometry *geometry;
 	unsigned int capacity;
@@ -156,6 +167,62 @@ struct sparse_cache {
 	struct cached_chapter_index chapters[];
 };
 
+static int uds_initialize_barrier(struct barrier *barrier, unsigned int thread_count)
+{
+	sema_init(&barrier->lock, 1);
+	barrier->arrived = 0;
+	barrier->thread_count = thread_count;
+	sema_init(&barrier->wait, 0);
+
+	return UDS_SUCCESS;
+}
+
+static int uds_destroy_barrier(struct barrier *barrier)
+{
+	return UDS_SUCCESS;
+}
+
+static inline void __down(struct semaphore *semaphore)
+{
+	/*
+	 * Do not use down(semaphore). Instead use down_interruptible so that
+	 * we do not get 120 second stall messages in kern.log.
+	 */
+	while (down_interruptible(semaphore) != 0) {
+		/*
+		 * If we're called from a user-mode process (e.g., "dmsetup
+		 * remove") while waiting for an operation that may take a
+		 * while (e.g., UDS index save), and a signal is sent (SIGINT,
+		 * SIGUSR2), then down_interruptible will not block. If that
+		 * happens, sleep briefly to avoid keeping the CPU locked up in
+		 * this loop. We could just call cond_resched, but then we'd
+		 * still keep consuming CPU time slices and swamp other threads
+		 * trying to do computational work. [VDO-4980]
+		 */
+		fsleep(1000);
+	}
+}
+
+static int uds_enter_barrier(struct barrier *barrier)
+{
+	__down(&barrier->lock);
+	if (++barrier->arrived == barrier->thread_count) {
+		/* last thread */
+		int i;
+
+		for (i = 1; i < barrier->thread_count; i++)
+			up(&barrier->wait);
+
+		barrier->arrived = 0;
+		up(&barrier->lock);
+	} else {
+		up(&barrier->lock);
+		__down(&barrier->wait);
+	}
+
+	return UDS_SUCCESS;
+}
+
 static int __must_check initialize_cached_chapter_index(struct cached_chapter_index *chapter,
 							const struct index_geometry *geometry)
 {

drivers/md/dm-vdo/uds-threads.c

@@ -135,59 +135,3 @@ int uds_join_threads(struct thread *thread)
 	uds_free(thread);
 	return UDS_SUCCESS;
 }
-
-static inline void __down(struct semaphore *semaphore)
-{
-	/*
-	 * Do not use down(semaphore). Instead use down_interruptible so that
-	 * we do not get 120 second stall messages in kern.log.
-	 */
-	while (down_interruptible(semaphore) != 0) {
-		/*
-		 * If we're called from a user-mode process (e.g., "dmsetup
-		 * remove") while waiting for an operation that may take a
-		 * while (e.g., UDS index save), and a signal is sent (SIGINT,
-		 * SIGUSR2), then down_interruptible will not block. If that
-		 * happens, sleep briefly to avoid keeping the CPU locked up in
-		 * this loop. We could just call cond_resched, but then we'd
-		 * still keep consuming CPU time slices and swamp other threads
-		 * trying to do computational work. [VDO-4980]
-		 */
-		fsleep(1000);
-	}
-}
-
-int uds_initialize_barrier(struct barrier *barrier, unsigned int thread_count)
-{
-	sema_init(&barrier->lock, 1);
-	barrier->arrived = 0;
-	barrier->thread_count = thread_count;
-	sema_init(&barrier->wait, 0);
-
-	return UDS_SUCCESS;
-}
-
-int uds_destroy_barrier(struct barrier *barrier)
-{
-	return UDS_SUCCESS;
-}
-
-int uds_enter_barrier(struct barrier *barrier)
-{
-	__down(&barrier->lock);
-	if (++barrier->arrived == barrier->thread_count) {
-		/* last thread */
-		int i;
-
-		for (i = 1; i < barrier->thread_count; i++)
-			up(&barrier->wait);
-
-		barrier->arrived = 0;
-		up(&barrier->lock);
-	} else {
-		up(&barrier->lock);
-		__down(&barrier->wait);
-	}
-
-	return UDS_SUCCESS;
-}

drivers/md/dm-vdo/uds-threads.h

@@ -24,16 +24,6 @@ struct cond_var {
 
 struct thread;
 
-struct barrier {
-	/* Lock for this barrier object */
-	struct semaphore lock;
-	/* Semaphore for threads waiting at the barrier */
-	struct semaphore wait;
-	/* Number of threads which have arrived */
-	int arrived;
-	/* Total number of threads using this barrier */
-	int thread_count;
-};
 
 int __must_check uds_create_thread(void (*thread_function)(void *), void *thread_data,
 				   const char *name, struct thread **new_thread);
@@ -42,11 +32,6 @@ void uds_perform_once(atomic_t *once_state, void (*function) (void));
 
 int uds_join_threads(struct thread *thread);
 
-int __must_check uds_initialize_barrier(struct barrier *barrier,
-					unsigned int thread_count);
-int uds_destroy_barrier(struct barrier *barrier);
-int uds_enter_barrier(struct barrier *barrier);
-
 int __must_check uds_init_cond(struct cond_var *cond);
 int uds_signal_cond(struct cond_var *cond);
 int uds_broadcast_cond(struct cond_var *cond);