staging: erofs: cleanup `z_erofs_vle_normalaccess_readpages'

This patch introduces `__should_decompress_synchronously' to
cleanup `z_erofs_vle_normalaccess_readpages'.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/erofs/internal.h

@@ -95,6 +95,9 @@ struct erofs_sb_info {
 	/* the dedicated workstation for compression */
 	struct radix_tree_root workstn_tree;
 
+	/* threshold for decompression synchronously */
+	unsigned int max_sync_decompress_pages;
+
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
 	struct inode *managed_cache;
 #endif
@@ -273,6 +276,14 @@ extern int erofs_try_to_free_cached_page(struct address_space *mapping,
 	struct page *page);
 #endif
 
+#define DEFAULT_MAX_SYNC_DECOMPRESS_PAGES	3
+
+static inline bool __should_decompress_synchronously(struct erofs_sb_info *sbi,
+						     unsigned int nr)
+{
+	return nr <= sbi->max_sync_decompress_pages;
+}
+
 #endif
 
 /* we strictly follow PAGE_SIZE and no buffer head yet */

drivers/staging/erofs/super.c

@@ -162,6 +162,11 @@ static void erofs_build_fault_attr(struct erofs_sb_info *sbi,
 
 static void default_options(struct erofs_sb_info *sbi)
 {
+	/* set up some FS parameters */
+#ifdef CONFIG_EROFS_FS_ZIP
+	sbi->max_sync_decompress_pages = DEFAULT_MAX_SYNC_DECOMPRESS_PAGES;
+#endif
+
 #ifdef CONFIG_EROFS_FS_XATTR
 	set_opt(sbi, XATTR_USER);
 #endif

drivers/staging/erofs/unzip_vle.c

@@ -1308,12 +1308,14 @@ out:
 	return 0;
 }
 
-static inline int __z_erofs_vle_normalaccess_readpages(
-	struct file *filp,
-	struct address_space *mapping,
-	struct list_head *pages, unsigned int nr_pages, bool sync)
+static int z_erofs_vle_normalaccess_readpages(struct file *filp,
+					      struct address_space *mapping,
+					      struct list_head *pages,
+					      unsigned int nr_pages)
 {
 	struct inode *const inode = mapping->host;
+	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
+	const bool sync = __should_decompress_synchronously(sbi, nr_pages);
 
 	struct z_erofs_vle_frontend f = VLE_FRONTEND_INIT(inode);
 	gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
@@ -1372,16 +1374,6 @@ static inline int __z_erofs_vle_normalaccess_readpages(
 	return 0;
 }
 
-static int z_erofs_vle_normalaccess_readpages(
-	struct file *filp,
-	struct address_space *mapping,
-	struct list_head *pages, unsigned int nr_pages)
-{
-	return __z_erofs_vle_normalaccess_readpages(filp,
-		mapping, pages, nr_pages,
-		nr_pages < 4 /* sync */);
-}
-
 const struct address_space_operations z_erofs_vle_normalaccess_aops = {
 	.readpage = z_erofs_vle_normalaccess_readpage,
 	.readpages = z_erofs_vle_normalaccess_readpages,