erofs: introduce physical cluster slab pools

Since multiple pcluster sizes could be used at once, the number of
compressed pages will become a variable factor. It's necessary to
introduce slab pools rather than a single slab cache now.

This limits the pclustersize to 1M (Z_EROFS_PCLUSTER_MAX_SIZE), and
get rid of the obsolete EROFS_FS_CLUSTER_PAGE_LIMIT, which has no
use now.

Link: https://lore.kernel.org/r/20210407043927.10623-4-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index b503b353d4ab..942ee69dff6a 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -10,6 +10,7 @@
 #include "internal.h"
 #include "zpvec.h"
 
+#define Z_EROFS_PCLUSTER_MAX_PAGES	(Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
 #define Z_EROFS_NR_INLINE_PAGEVECS      3
 
 /*
@@ -59,16 +60,17 @@ struct z_erofs_pcluster {
 	/* A: point to next chained pcluster or TAILs */
 	z_erofs_next_pcluster_t next;
 
-	/* A: compressed pages (including multi-usage pages) */
-	struct page *compressed_pages[Z_EROFS_CLUSTER_MAX_PAGES];
-
 	/* A: lower limit of decompressed length and if full length or not */
 	unsigned int length;
 
+	/* I: physical cluster size in pages */
+	unsigned short pclusterpages;
+
 	/* I: compression algorithm format */
 	unsigned char algorithmformat;
-	/* I: bit shift of physical cluster size */
-	unsigned char clusterbits;
+
+	/* A: compressed pages (can be cached or inplaced pages) */
+	struct page *compressed_pages[];
 };
 
 #define z_erofs_primarycollection(pcluster) (&(pcluster)->primary_collection)
@@ -82,8 +84,6 @@ struct z_erofs_pcluster {
 
 #define Z_EROFS_PCLUSTER_NIL            (NULL)
 
-#define Z_EROFS_WORKGROUP_SIZE  sizeof(struct z_erofs_pcluster)
-
 struct z_erofs_decompressqueue {
 	struct super_block *sb;
 	atomic_t pending_bios;