btrfs: add compression interface in (get/put)_workspace
[sfrench/cifs-2.6.git] / fs / btrfs / compression.c
index 548057630b69e9735d75eb1426869c85c0e521e9..0240649fb3ac4846b9f8fdc8490cbd32b712f962 100644 (file)
@@ -769,7 +769,13 @@ fail:
        return ERR_PTR(-ENOMEM);
 }
 
-struct workspaces_list {
+const struct btrfs_compress_op btrfs_heuristic_compress = {
+       .alloc_workspace = alloc_heuristic_ws,
+       .free_workspace = free_heuristic_ws,
+};
+
+struct workspace_manager {
+       const struct btrfs_compress_op *ops;
        struct list_head idle_ws;
        spinlock_t ws_lock;
        /* Number of free workspaces */
@@ -780,54 +786,52 @@ struct workspaces_list {
        wait_queue_head_t ws_wait;
 };
 
-static struct workspaces_list btrfs_comp_ws[BTRFS_COMPRESS_TYPES];
-
-static struct workspaces_list btrfs_heuristic_ws;
+static struct workspace_manager wsm[BTRFS_NR_WORKSPACE_MANAGERS];
 
 static const struct btrfs_compress_op * const btrfs_compress_op[] = {
+       /* The heuristic is represented as compression type 0 */
+       &btrfs_heuristic_compress,
        &btrfs_zlib_compress,
        &btrfs_lzo_compress,
        &btrfs_zstd_compress,
 };
 
-void __init btrfs_init_compress(void)
+static void btrfs_init_workspace_manager(int type)
 {
+       struct workspace_manager *wsman = &wsm[type];
        struct list_head *workspace;
-       int i;
 
-       INIT_LIST_HEAD(&btrfs_heuristic_ws.idle_ws);
-       spin_lock_init(&btrfs_heuristic_ws.ws_lock);
-       atomic_set(&btrfs_heuristic_ws.total_ws, 0);
-       init_waitqueue_head(&btrfs_heuristic_ws.ws_wait);
+       wsman->ops = btrfs_compress_op[type];
 
-       workspace = alloc_heuristic_ws();
+       INIT_LIST_HEAD(&wsman->idle_ws);
+       spin_lock_init(&wsman->ws_lock);
+       atomic_set(&wsman->total_ws, 0);
+       init_waitqueue_head(&wsman->ws_wait);
+
+       /*
+        * Preallocate one workspace for each compression type so we can
+        * guarantee forward progress in the worst case
+        */
+       workspace = wsman->ops->alloc_workspace();
        if (IS_ERR(workspace)) {
                pr_warn(
-       "BTRFS: cannot preallocate heuristic workspace, will try later\n");
+       "BTRFS: cannot preallocate compression workspace, will try later\n");
        } else {
-               atomic_set(&btrfs_heuristic_ws.total_ws, 1);
-               btrfs_heuristic_ws.free_ws = 1;
-               list_add(workspace, &btrfs_heuristic_ws.idle_ws);
+               atomic_set(&wsman->total_ws, 1);
+               wsman->free_ws = 1;
+               list_add(workspace, &wsman->idle_ws);
        }
+}
 
-       for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
-               INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws);
-               spin_lock_init(&btrfs_comp_ws[i].ws_lock);
-               atomic_set(&btrfs_comp_ws[i].total_ws, 0);
-               init_waitqueue_head(&btrfs_comp_ws[i].ws_wait);
+static void btrfs_cleanup_workspace_manager(struct workspace_manager *wsman)
+{
+       struct list_head *ws;
 
-               /*
-                * Preallocate one workspace for each compression type so
-                * we can guarantee forward progress in the worst case
-                */
-               workspace = btrfs_compress_op[i]->alloc_workspace();
-               if (IS_ERR(workspace)) {
-                       pr_warn("BTRFS: cannot preallocate compression workspace, will try later\n");
-               } else {
-                       atomic_set(&btrfs_comp_ws[i].total_ws, 1);
-                       btrfs_comp_ws[i].free_ws = 1;
-                       list_add(workspace, &btrfs_comp_ws[i].idle_ws);
-               }
+       while (!list_empty(&wsman->idle_ws)) {
+               ws = wsman->idle_ws.next;
+               list_del(ws);
+               wsman->ops->free_workspace(ws);
+               atomic_dec(&wsman->total_ws);
        }
 }
 
@@ -837,11 +841,10 @@ void __init btrfs_init_compress(void)
  * Preallocation makes a forward progress guarantees and we do not return
  * errors.
  */
-static struct list_head *__find_workspace(int type, bool heuristic)
+static struct list_head *btrfs_get_workspace(struct workspace_manager *wsman)
 {
        struct list_head *workspace;
        int cpus = num_online_cpus();
-       int idx = type - 1;
        unsigned nofs_flag;
        struct list_head *idle_ws;
        spinlock_t *ws_lock;
@@ -849,19 +852,11 @@ static struct list_head *__find_workspace(int type, bool heuristic)
        wait_queue_head_t *ws_wait;
        int *free_ws;
 
-       if (heuristic) {
-               idle_ws  = &btrfs_heuristic_ws.idle_ws;
-               ws_lock  = &btrfs_heuristic_ws.ws_lock;
-               total_ws = &btrfs_heuristic_ws.total_ws;
-               ws_wait  = &btrfs_heuristic_ws.ws_wait;
-               free_ws  = &btrfs_heuristic_ws.free_ws;
-       } else {
-               idle_ws  = &btrfs_comp_ws[idx].idle_ws;
-               ws_lock  = &btrfs_comp_ws[idx].ws_lock;
-               total_ws = &btrfs_comp_ws[idx].total_ws;
-               ws_wait  = &btrfs_comp_ws[idx].ws_wait;
-               free_ws  = &btrfs_comp_ws[idx].free_ws;
-       }
+       idle_ws  = &wsman->idle_ws;
+       ws_lock  = &wsman->ws_lock;
+       total_ws = &wsman->total_ws;
+       ws_wait  = &wsman->ws_wait;
+       free_ws  = &wsman->free_ws;
 
 again:
        spin_lock(ws_lock);
@@ -892,10 +887,7 @@ again:
         * context of btrfs_compress_bio/btrfs_compress_pages
         */
        nofs_flag = memalloc_nofs_save();
-       if (heuristic)
-               workspace = alloc_heuristic_ws();
-       else
-               workspace = btrfs_compress_op[idx]->alloc_workspace();
+       workspace = wsman->ops->alloc_workspace();
        memalloc_nofs_restore(nofs_flag);
 
        if (IS_ERR(workspace)) {
@@ -926,85 +918,48 @@ again:
        return workspace;
 }
 
-static struct list_head *find_workspace(int type)
+static struct list_head *get_workspace(int type)
 {
-       return __find_workspace(type, false);
+       return btrfs_get_workspace(&wsm[type]);
 }
 
 /*
  * put a workspace struct back on the list or free it if we have enough
  * idle ones sitting around
  */
-static void __free_workspace(int type, struct list_head *workspace,
-                            bool heuristic)
+static void btrfs_put_workspace(struct workspace_manager *wsman,
+                               struct list_head *ws)
 {
-       int idx = type - 1;
        struct list_head *idle_ws;
        spinlock_t *ws_lock;
        atomic_t *total_ws;
        wait_queue_head_t *ws_wait;
        int *free_ws;
 
-       if (heuristic) {
-               idle_ws  = &btrfs_heuristic_ws.idle_ws;
-               ws_lock  = &btrfs_heuristic_ws.ws_lock;
-               total_ws = &btrfs_heuristic_ws.total_ws;
-               ws_wait  = &btrfs_heuristic_ws.ws_wait;
-               free_ws  = &btrfs_heuristic_ws.free_ws;
-       } else {
-               idle_ws  = &btrfs_comp_ws[idx].idle_ws;
-               ws_lock  = &btrfs_comp_ws[idx].ws_lock;
-               total_ws = &btrfs_comp_ws[idx].total_ws;
-               ws_wait  = &btrfs_comp_ws[idx].ws_wait;
-               free_ws  = &btrfs_comp_ws[idx].free_ws;
-       }
+       idle_ws  = &wsman->idle_ws;
+       ws_lock  = &wsman->ws_lock;
+       total_ws = &wsman->total_ws;
+       ws_wait  = &wsman->ws_wait;
+       free_ws  = &wsman->free_ws;
 
        spin_lock(ws_lock);
        if (*free_ws <= num_online_cpus()) {
-               list_add(workspace, idle_ws);
+               list_add(ws, idle_ws);
                (*free_ws)++;
                spin_unlock(ws_lock);
                goto wake;
        }
        spin_unlock(ws_lock);
 
-       if (heuristic)
-               free_heuristic_ws(workspace);
-       else
-               btrfs_compress_op[idx]->free_workspace(workspace);
+       wsman->ops->free_workspace(ws);
        atomic_dec(total_ws);
 wake:
        cond_wake_up(ws_wait);
 }
 
-static void free_workspace(int type, struct list_head *ws)
+static void put_workspace(int type, struct list_head *ws)
 {
-       return __free_workspace(type, ws, false);
-}
-
-/*
- * cleanup function for module exit
- */
-static void free_workspaces(void)
-{
-       struct list_head *workspace;
-       int i;
-
-       while (!list_empty(&btrfs_heuristic_ws.idle_ws)) {
-               workspace = btrfs_heuristic_ws.idle_ws.next;
-               list_del(workspace);
-               free_heuristic_ws(workspace);
-               atomic_dec(&btrfs_heuristic_ws.total_ws);
-       }
-
-       for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
-               while (!list_empty(&btrfs_comp_ws[i].idle_ws)) {
-                       workspace = btrfs_comp_ws[i].idle_ws.next;
-                       list_del(workspace);
-                       btrfs_compress_op[i]->free_workspace(workspace);
-                       atomic_dec(&btrfs_comp_ws[i].total_ws);
-               }
-       }
+       return btrfs_put_workspace(&wsm[type], ws);
 }
 
 /*
@@ -1036,18 +991,18 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
                         unsigned long *total_in,
                         unsigned long *total_out)
 {
+       int type = btrfs_compress_type(type_level);
        struct list_head *workspace;
        int ret;
-       int type = type_level & 0xF;
 
-       workspace = find_workspace(type);
+       workspace = get_workspace(type);
 
-       btrfs_compress_op[type - 1]->set_level(workspace, type_level);
-       ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
+       btrfs_compress_op[type]->set_level(workspace, type_level);
+       ret = btrfs_compress_op[type]->compress_pages(workspace, mapping,
                                                      start, pages,
                                                      out_pages,
                                                      total_in, total_out);
-       free_workspace(type, workspace);
+       put_workspace(type, workspace);
        return ret;
 }
 
@@ -1071,9 +1026,9 @@ static int btrfs_decompress_bio(struct compressed_bio *cb)
        int ret;
        int type = cb->compress_type;
 
-       workspace = find_workspace(type);
-       ret = btrfs_compress_op[type - 1]->decompress_bio(workspace, cb);
-       free_workspace(type, workspace);
+       workspace = get_workspace(type);
+       ret = btrfs_compress_op[type]->decompress_bio(workspace, cb);
+       put_workspace(type, workspace);
 
        return ret;
 }
@@ -1089,19 +1044,30 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
        struct list_head *workspace;
        int ret;
 
-       workspace = find_workspace(type);
+       workspace = get_workspace(type);
 
-       ret = btrfs_compress_op[type-1]->decompress(workspace, data_in,
+       ret = btrfs_compress_op[type]->decompress(workspace, data_in,
                                                  dest_page, start_byte,
                                                  srclen, destlen);
 
-       free_workspace(type, workspace);
+       put_workspace(type, workspace);
        return ret;
 }
 
+void __init btrfs_init_compress(void)
+{
+       int i;
+
+       for (i = 0; i < BTRFS_NR_WORKSPACE_MANAGERS; i++)
+               btrfs_init_workspace_manager(i);
+}
+
 void __cold btrfs_exit_compress(void)
 {
-       free_workspaces();
+       int i;
+
+       for (i = 0; i < BTRFS_NR_WORKSPACE_MANAGERS; i++)
+               btrfs_cleanup_workspace_manager(&wsm[i]);
 }
 
 /*
@@ -1512,7 +1478,7 @@ static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end,
  */
 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
 {
-       struct list_head *ws_list = __find_workspace(0, true);
+       struct list_head *ws_list = get_workspace(0);
        struct heuristic_ws *ws;
        u32 i;
        u8 byte;
@@ -1581,7 +1547,7 @@ int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
        }
 
 out:
-       __free_workspace(0, ws_list, true);
+       put_workspace(0, ws_list);
        return ret;
 }