erofs: rename some generic methods in decompressor

Previously, some LZ4 methods were named with `generic'. However, while
evaluating the effective LZMA approach, it seems they aren't quite
generic at all (e.g. no need preparing dstpages for most LZMA cases.)

Avoid such naming instead.

Link: https://lore.kernel.org/r/20211010213145.17462-7-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index dce06ac61893350fbbd0ccfb479d86742b4b1628..8fd7af9d6b38023c47c224e9c77db36fe7484a8d 100644 (file)
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -17,13 +17,8 @@
 #endif
 
 struct z_erofs_decompressor {
-       /*
-        * if destpages have sparsed pages, fill them with bounce pages.
-        * it also check whether destpages indicate continuous physical memory.
-        */
-       int (*prepare_destpages)(struct z_erofs_decompress_req *rq,
-                                struct list_head *pagepool);
-       int (*decompress)(struct z_erofs_decompress_req *rq, u8 *out);
+       int (*decompress)(struct z_erofs_decompress_req *rq,
+                         struct list_head *pagepool);
        char *name;
 };
 
@@ -63,8 +58,12 @@ int z_erofs_load_lz4_config(struct super_block *sb,
        return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
 }
 
-static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
-                                        struct list_head *pagepool)
+/*
+ * Fill all gaps with bounce pages if it's a sparse page list. Also check if
+ * all physical pages are consecutive, which can be seen for moderate CR.
+ */
+static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
+                                       struct list_head *pagepool)
 {
        const unsigned int nr =
                PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -119,7 +118,7 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
        return kaddr ? 1 : 0;
 }
 
-static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
+static void *z_erofs_lz4_handle_inplace_io(struct z_erofs_decompress_req *rq,
                        void *inpage, unsigned int *inputmargin, int *maptype,
                        bool support_0padding)
 {
@@ -189,7 +188,8 @@ docopy:
        return src;
 }
 
-static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
+                                     u8 *out)
 {
        unsigned int inputmargin;
        u8 *headpage, *src;
@@ -216,8 +216,8 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
        }
 
        rq->inputsize -= inputmargin;
-       src = z_erofs_handle_inplace_io(rq, headpage, &inputmargin, &maptype,
-                                       support_0padding);
+       src = z_erofs_lz4_handle_inplace_io(rq, headpage, &inputmargin,
+                                           &maptype, support_0padding);
        if (IS_ERR(src))
                return PTR_ERR(src);
 
@@ -259,23 +259,11 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
        return ret;
 }
 
-static struct z_erofs_decompressor decompressors[] = {
-       [Z_EROFS_COMPRESSION_SHIFTED] = {
-               .name = "shifted"
-       },
-       [Z_EROFS_COMPRESSION_LZ4] = {
-               .prepare_destpages = z_erofs_lz4_prepare_destpages,
-               .decompress = z_erofs_lz4_decompress,
-               .name = "lz4"
-       },
-};
-
-static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
-                                     struct list_head *pagepool)
+static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
+                                 struct list_head *pagepool)
 {
        const unsigned int nrpages_out =
                PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
-       const struct z_erofs_decompressor *alg = decompressors + rq->alg;
        unsigned int dst_maptype;
        void *dst;
        int ret;
@@ -289,7 +277,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
        }
 
        /* general decoding path which can be used for all cases */
-       ret = alg->prepare_destpages(rq, pagepool);
+       ret = z_erofs_lz4_prepare_dstpages(rq, pagepool);
        if (ret < 0)
                return ret;
        if (ret) {
@@ -304,7 +292,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
        dst_maptype = 2;
 
 dstmap_out:
-       ret = alg->decompress(rq, dst + rq->pageofs_out);
+       ret = z_erofs_lz4_decompress_mem(rq, dst + rq->pageofs_out);
 
        if (!dst_maptype)
                kunmap_atomic(dst);
@@ -313,7 +301,7 @@ dstmap_out:
        return ret;
 }
 
-static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
+static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
                                     struct list_head *pagepool)
 {
        const unsigned int nrpages_out =
@@ -352,10 +340,19 @@ static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
        return 0;
 }
 
+static struct z_erofs_decompressor decompressors[] = {
+       [Z_EROFS_COMPRESSION_SHIFTED] = {
+               .decompress = z_erofs_shifted_transform,
+               .name = "shifted"
+       },
+       [Z_EROFS_COMPRESSION_LZ4] = {
+               .decompress = z_erofs_lz4_decompress,
+               .name = "lz4"
+       },
+};
+
 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
                       struct list_head *pagepool)
 {
-       if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
-               return z_erofs_shifted_transform(rq, pagepool);
-       return z_erofs_decompress_generic(rq, pagepool);
+       return decompressors[rq->alg].decompress(rq, pagepool);
 }