erofs: fold in z_erofs_decompress()

No need this helper since it's just a simple wrapper for decompress
method and only one caller.  So, let's fold in directly instead.
Signed-off-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230426084449.12781-1-zbestahu@gmail.comSigned-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

fs/erofs/compress.h

@@ -89,8 +89,7 @@ static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
 
 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 			 unsigned int padbufsize);
-int z_erofs_decompress(struct z_erofs_decompress_req *rq,
-		       struct page **pagepool);
+extern const struct z_erofs_decompressor erofs_decompressors[];
 
 /* prototypes for specific algorithms */
 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,

fs/erofs/decompressor.c

@@ -363,7 +363,7 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
 	return 0;
 }
 
-static struct z_erofs_decompressor decompressors[] = {
+const struct z_erofs_decompressor erofs_decompressors[] = {
 	[Z_EROFS_COMPRESSION_SHIFTED] = {
 		.decompress = z_erofs_transform_plain,
 		.name = "shifted"
@@ -383,9 +383,3 @@ static struct z_erofs_decompressor decompressors[] = {
 	},
 #endif
 };
-
-int z_erofs_decompress(struct z_erofs_decompress_req *rq,
-		       struct page **pagepool)
-{
-	return decompressors[rq->alg].decompress(rq, pagepool);
-}

fs/erofs/zdata.c

@@ -1283,6 +1283,8 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
 	struct erofs_sb_info *const sbi = EROFS_SB(be->sb);
 	struct z_erofs_pcluster *pcl = be->pcl;
 	unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+	const struct z_erofs_decompressor *decompressor =
+				&erofs_decompressors[pcl->algorithmformat];
 	unsigned int i, inputsize;
 	int err2;
 	struct page *page;
@@ -1326,7 +1328,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
 	else
 		inputsize = pclusterpages * PAGE_SIZE;
 
-	err = z_erofs_decompress(&(struct z_erofs_decompress_req) {
+	err = decompressor->decompress(&(struct z_erofs_decompress_req) {
 					.sb = be->sb,
 					.in = be->compressed_pages,
 					.out = be->decompressed_pages,