diff options
Diffstat (limited to 'fs/erofs/zdata.h')
| -rw-r--r-- | fs/erofs/zdata.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h new file mode 100644 index 000000000000..4fc547bc01f9 --- /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); + } + debugln("%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 + |