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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2018 HUAWEI, Inc.
* https://www.huawei.com/
*/
#ifndef __EROFS_FS_ZDATA_H
#define __EROFS_FS_ZDATA_H
#include "internal.h"
#include "tagptr.h"
#define Z_EROFS_PCLUSTER_MAX_PAGES (Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
#define Z_EROFS_INLINE_BVECS 2
/*
* let's leave a type here in case of introducing
* another tagged pointer later.
*/
typedef void *z_erofs_next_pcluster_t;
struct z_erofs_bvec {
struct page *page;
int offset;
unsigned int end;
};
#define __Z_EROFS_BVSET(name, total) \
struct name { \
/* point to the next page which contains the following bvecs */ \
struct page *nextpage; \
struct z_erofs_bvec bvec[total]; \
}
__Z_EROFS_BVSET(z_erofs_bvset,);
__Z_EROFS_BVSET(z_erofs_bvset_inline, Z_EROFS_INLINE_BVECS);
/*
* 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 the pcluster lock;
*
* A: Field should be accessed / updated in atomic for parallelized code.
*/
struct z_erofs_pcluster {
struct erofs_workgroup obj;
struct mutex lock;
/* A: point to next chained pcluster or TAILs */
z_erofs_next_pcluster_t next;
/* L: the maximum decompression size of this round */
unsigned int length;
/* L: total number of bvecs */
unsigned int vcnt;
/* I: page offset of start position of decompression */
unsigned short pageofs_out;
/* I: page offset of inline compressed data */
unsigned short pageofs_in;
union {
/* L: inline a certain number of bvec for bootstrap */
struct z_erofs_bvset_inline bvset;
/* I: can be used to free the pcluster by RCU. */
struct rcu_head rcu;
};
union {
/* I: physical cluster size in pages */
unsigned short pclusterpages;
/* I: tailpacking inline compressed size */
unsigned short tailpacking_size;
};
/* I: compression algorithm format */
unsigned char algorithmformat;
/* L: whether partial decompression or not */
bool partial;
/* L: indicate several pageofs_outs or not */
bool multibases;
/* A: compressed bvecs (can be cached or inplaced pages) */
struct z_erofs_bvec compressed_bvecs[];
};
/* 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)
struct z_erofs_decompressqueue {
struct super_block *sb;
atomic_t pending_bios;
z_erofs_next_pcluster_t head;
union {
struct completion done;
struct work_struct work;
} u;
bool eio, sync;
};
static inline bool z_erofs_is_inline_pcluster(struct z_erofs_pcluster *pcl)
{
return !pcl->obj.index;
}
static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
{
if (z_erofs_is_inline_pcluster(pcl))
return 1;
return pcl->pclusterpages;
}
/*
* bit 30: I/O error occurred on this page
* bit 0 - 29: remaining parts to complete this page
*/
#define Z_EROFS_PAGE_EIO (1 << 30)
static inline void z_erofs_onlinepage_init(struct page *page)
{
union {
atomic_t o;
unsigned long v;
} u = { .o = ATOMIC_INIT(1) };
set_page_private(page, u.v);
smp_wmb();
SetPagePrivate(page);
}
static inline void z_erofs_onlinepage_split(struct page *page)
{
atomic_inc((atomic_t *)&page->private);
}
static inline void z_erofs_page_mark_eio(struct page *page)
{
int orig;
do {
orig = atomic_read((atomic_t *)&page->private);
} while (atomic_cmpxchg((atomic_t *)&page->private, orig,
orig | Z_EROFS_PAGE_EIO) != orig);
}
static inline void z_erofs_onlinepage_endio(struct page *page)
{
unsigned int v;
DBG_BUGON(!PagePrivate(page));
v = atomic_dec_return((atomic_t *)&page->private);
if (!(v & ~Z_EROFS_PAGE_EIO)) {
set_page_private(page, 0);
ClearPagePrivate(page);
if (!(v & Z_EROFS_PAGE_EIO))
SetPageUptodate(page);
unlock_page(page);
}
}
#define Z_EROFS_ONSTACK_PAGES 32
#endif
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