f2fs: compress: add .{init,destroy}_decompress_ctx callback

Add below two callback interfaces in struct f2fs_compress_ops:

	int (*init_decompress_ctx)(struct decompress_io_ctx *dic);
	void (*destroy_decompress_ctx)(struct decompress_io_ctx *dic);

Which will be used by zstd compress algorithm later.

In addition, this patch adds callback function pointer check, so that
specified algorithm can avoid defining unneeded functions.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 1e5bbb9c1d3ed801f66a0abb7580fb0a8435e03a..13666735f56757c06cfd431ab0fa3bc0d8b62fc7 100644 (file)
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -20,6 +20,8 @@ struct f2fs_compress_ops {
        int (*init_compress_ctx)(struct compress_ctx *cc);
        void (*destroy_compress_ctx)(struct compress_ctx *cc);
        int (*compress_pages)(struct compress_ctx *cc);
+       int (*init_decompress_ctx)(struct decompress_io_ctx *dic);
+       void (*destroy_decompress_ctx)(struct decompress_io_ctx *dic);
        int (*decompress_pages)(struct decompress_io_ctx *dic);
 };
 
@@ -332,9 +334,11 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
        trace_f2fs_compress_pages_start(cc->inode, cc->cluster_idx,
                                cc->cluster_size, fi->i_compress_algorithm);
 
-       ret = cops->init_compress_ctx(cc);
-       if (ret)
-               goto out;
+       if (cops->init_compress_ctx) {
+               ret = cops->init_compress_ctx(cc);
+               if (ret)
+                       goto out;
+       }
 
        max_len = COMPRESS_HEADER_SIZE + cc->clen;
        cc->nr_cpages = DIV_ROUND_UP(max_len, PAGE_SIZE);
@@ -396,7 +400,8 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
                cc->cpages[i] = NULL;
        }
 
-       cops->destroy_compress_ctx(cc);
+       if (cops->destroy_compress_ctx)
+               cops->destroy_compress_ctx(cc);
 
        cc->nr_cpages = nr_cpages;
 
@@ -416,7 +421,8 @@ out_free_cpages:
        kfree(cc->cpages);
        cc->cpages = NULL;
 destroy_compress_ctx:
-       cops->destroy_compress_ctx(cc);
+       if (cops->destroy_compress_ctx)
+               cops->destroy_compress_ctx(cc);
 out:
        trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
                                                        cc->clen, ret);
@@ -450,10 +456,16 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
                goto out_free_dic;
        }
 
+       if (cops->init_decompress_ctx) {
+               ret = cops->init_decompress_ctx(dic);
+               if (ret)
+                       goto out_free_dic;
+       }
+
        dic->rbuf = vmap(dic->tpages, dic->cluster_size, VM_MAP, PAGE_KERNEL);
        if (!dic->rbuf) {
                ret = -ENOMEM;
-               goto out_free_dic;
+               goto destroy_decompress_ctx;
        }
 
        dic->cbuf = vmap(dic->cpages, dic->nr_cpages, VM_MAP, PAGE_KERNEL_RO);
@@ -476,6 +488,9 @@ out_vunmap_cbuf:
        vunmap(dic->cbuf);
 out_vunmap_rbuf:
        vunmap(dic->rbuf);
+destroy_decompress_ctx:
+       if (cops->destroy_decompress_ctx)
+               cops->destroy_decompress_ctx(dic);
 out_free_dic:
        if (verity)
                refcount_set(&dic->ref, dic->nr_cpages);