Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
new file mode 100644
index 0000000..faf9501
--- /dev/null
+++ b/fs/erofs/zdata.h
@@ -0,0 +1,193 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2018 HUAWEI, Inc.
+ * http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_ZDATA_H
+#define __EROFS_FS_ZDATA_H
+
+#include "internal.h"
+#include "zpvec.h"
+
+#define Z_EROFS_NR_INLINE_PAGEVECS 3
+
+/*
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Modifiable by initialization/destruction paths and read-only
+ * for everyone else;
+ *
+ * L: Field should be protected by pageset lock;
+ *
+ * A: Field should be accessed / updated in atomic for parallelized code.
+ */
+struct z_erofs_collection {
+ struct mutex lock;
+
+ /* I: page offset of start position of decompression */
+ unsigned short pageofs;
+
+ /* L: maximum relative page index in pagevec[] */
+ unsigned short nr_pages;
+
+ /* L: total number of pages in pagevec[] */
+ unsigned int vcnt;
+
+ union {
+ /* L: inline a certain number of pagevecs for bootstrap */
+ erofs_vtptr_t pagevec[Z_EROFS_NR_INLINE_PAGEVECS];
+
+ /* I: can be used to free the pcluster by RCU. */
+ struct rcu_head rcu;
+ };
+};
+
+#define Z_EROFS_PCLUSTER_FULL_LENGTH 0x00000001
+#define Z_EROFS_PCLUSTER_LENGTH_BIT 1
+
+/*
+ * let's leave a type here in case of introducing
+ * another tagged pointer later.
+ */
+typedef void *z_erofs_next_pcluster_t;
+
+struct z_erofs_pcluster {
+ struct erofs_workgroup obj;
+ struct z_erofs_collection primary_collection;
+
+ /* 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: compression algorithm format */
+ unsigned char algorithmformat;
+ /* I: bit shift of physical cluster size */
+ unsigned char clusterbits;
+};
+
+#define z_erofs_primarycollection(pcluster) (&(pcluster)->primary_collection)
+
+/* let's avoid the valid 32-bit kernel addresses */
+
+/* the chained workgroup has't submitted io (still open) */
+#define Z_EROFS_PCLUSTER_TAIL ((void *)0x5F0ECAFE)
+/* the chained workgroup has already submitted io */
+#define Z_EROFS_PCLUSTER_TAIL_CLOSED ((void *)0x5F0EDEAD)
+
+#define Z_EROFS_PCLUSTER_NIL (NULL)
+
+#define Z_EROFS_WORKGROUP_SIZE sizeof(struct z_erofs_pcluster)
+
+struct z_erofs_unzip_io {
+ atomic_t pending_bios;
+ z_erofs_next_pcluster_t head;
+
+ union {
+ wait_queue_head_t wait;
+ struct work_struct work;
+ } u;
+};
+
+struct z_erofs_unzip_io_sb {
+ struct z_erofs_unzip_io io;
+ struct super_block *sb;
+};
+
+#define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping)
+static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
+ struct page *page)
+{
+ return page->mapping == MNGD_MAPPING(sbi);
+}
+
+#define Z_EROFS_ONLINEPAGE_COUNT_BITS 2
+#define Z_EROFS_ONLINEPAGE_COUNT_MASK ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
+#define Z_EROFS_ONLINEPAGE_INDEX_SHIFT (Z_EROFS_ONLINEPAGE_COUNT_BITS)
+
+/*
+ * waiters (aka. ongoing_packs): # to unlock the page
+ * sub-index: 0 - for partial page, >= 1 full page sub-index
+ */
+typedef atomic_t z_erofs_onlinepage_t;
+
+/* type punning */
+union z_erofs_onlinepage_converter {
+ z_erofs_onlinepage_t *o;
+ unsigned long *v;
+};
+
+static inline unsigned int z_erofs_onlinepage_index(struct page *page)
+{
+ union z_erofs_onlinepage_converter u;
+
+ DBG_BUGON(!PagePrivate(page));
+ u.v = &page_private(page);
+
+ return atomic_read(u.o) >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
+}
+
+static inline void z_erofs_onlinepage_init(struct page *page)
+{
+ union {
+ z_erofs_onlinepage_t o;
+ unsigned long v;
+ /* keep from being unlocked in advance */
+ } u = { .o = ATOMIC_INIT(1) };
+
+ set_page_private(page, u.v);
+ smp_wmb();
+ SetPagePrivate(page);
+}
+
+static inline void z_erofs_onlinepage_fixup(struct page *page,
+ uintptr_t index, bool down)
+{
+ unsigned long *p, o, v, id;
+repeat:
+ p = &page_private(page);
+ o = READ_ONCE(*p);
+
+ id = o >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
+ if (id) {
+ if (!index)
+ return;
+
+ DBG_BUGON(id != index);
+ }
+
+ v = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) |
+ ((o & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down);
+ if (cmpxchg(p, o, v) != o)
+ goto repeat;
+}
+
+static inline void z_erofs_onlinepage_endio(struct page *page)
+{
+ union z_erofs_onlinepage_converter u;
+ unsigned int v;
+
+ DBG_BUGON(!PagePrivate(page));
+ u.v = &page_private(page);
+
+ v = atomic_dec_return(u.o);
+ if (!(v & Z_EROFS_ONLINEPAGE_COUNT_MASK)) {
+ ClearPagePrivate(page);
+ if (!PageError(page))
+ SetPageUptodate(page);
+ unlock_page(page);
+ }
+ erofs_dbg("%s, page %p value %x", __func__, page, atomic_read(u.o));
+}
+
+#define Z_EROFS_VMAP_ONSTACK_PAGES \
+ min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
+#define Z_EROFS_VMAP_GLOBAL_PAGES 2048
+
+#endif
+