btrfs: move to function pointers for get/put workspaces

The previous patch added generic helpers for get_workspace() and
put_workspace(). Now, we can migrate ownership of the workspace_manager
to be in the compression type code as the compression code itself
doesn't care beyond being able to get a workspace. The init/cleanup and
get/put methods are abstracted so each compression algorithm can decide
how they want to manage their workspaces.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 9a0e73c65b87..e298aa9e6b33 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -107,7 +107,33 @@ enum btrfs_compression_type {
 	BTRFS_COMPRESS_TYPES = 3,
 };
 
+struct workspace_manager {
+	const struct btrfs_compress_op *ops;
+	struct list_head idle_ws;
+	spinlock_t ws_lock;
+	/* Number of free workspaces */
+	int free_ws;
+	/* Total number of allocated workspaces */
+	atomic_t total_ws;
+	/* Waiters for a free workspace */
+	wait_queue_head_t ws_wait;
+};
+
+void btrfs_init_workspace_manager(struct workspace_manager *wsm,
+				  const struct btrfs_compress_op *ops);
+struct list_head *btrfs_get_workspace(struct workspace_manager *wsm);
+void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws);
+void btrfs_cleanup_workspace_manager(struct workspace_manager *wsm);
+
 struct btrfs_compress_op {
+	void (*init_workspace_manager)(void);
+
+	void (*cleanup_workspace_manager)(void);
+
+	struct list_head *(*get_workspace)(void);
+
+	void (*put_workspace)(struct list_head *ws);
+
 	struct list_head *(*alloc_workspace)(void);
 
 	void (*free_workspace)(struct list_head *workspace);