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Code Issues Releases Wiki Activity

erofs: remove tagged pointer helpers

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Just open-code the remaining one to simplify the code.

Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230204093040.97967-3-hsiangkao@linux.alibaba.com
This commit is contained in:
Gao Xiang 2023-02-04 17:30:37 +08:00
parent cdba55067f
commit b1ed220c62
3 changed files with 6 additions and 128 deletions
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107
fs/erofs/tagptr.h
View file

@ -1,107 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* A tagged pointer implementation
*/
#ifndef __EROFS_FS_TAGPTR_H
#define __EROFS_FS_TAGPTR_H
#include <linux/types.h>
#include <linux/build_bug.h>
/*
* the name of tagged pointer types are tagptr{1, 2, 3...}_t
* avoid directly using the internal structs __tagptr{1, 2, 3...}
*/
#define __MAKE_TAGPTR(n) \
typedef struct __tagptr##n { \
uintptr_t v; \
} tagptr##n##_t;
__MAKE_TAGPTR(1)
__MAKE_TAGPTR(2)
__MAKE_TAGPTR(3)
__MAKE_TAGPTR(4)
#undef __MAKE_TAGPTR
extern void __compiletime_error("bad tagptr tags")
__bad_tagptr_tags(void);
extern void __compiletime_error("bad tagptr type")
__bad_tagptr_type(void);
/* fix the broken usage of "#define tagptr2_t tagptr3_t" by users */
#define __tagptr_mask_1(ptr, n) \
__builtin_types_compatible_p(typeof(ptr), struct __tagptr##n) ? \
(1UL << (n)) - 1 :
#define __tagptr_mask(ptr) (\
__tagptr_mask_1(ptr, 1) ( \
__tagptr_mask_1(ptr, 2) ( \
__tagptr_mask_1(ptr, 3) ( \
__tagptr_mask_1(ptr, 4) ( \
__bad_tagptr_type(), 0)))))
/* generate a tagged pointer from a raw value */
#define tagptr_init(type, val) \
((typeof(type)){ .v = (uintptr_t)(val) })
/*
* directly cast a tagged pointer to the native pointer type, which
* could be used for backward compatibility of existing code.
*/
#define tagptr_cast_ptr(tptr) ((void *)(tptr).v)
/* encode tagged pointers */
#define tagptr_fold(type, ptr, _tags) ({ \
const typeof(_tags) tags = (_tags); \
if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(type))) \
__bad_tagptr_tags(); \
tagptr_init(type, (uintptr_t)(ptr) | tags); })
/* decode tagged pointers */
#define tagptr_unfold_ptr(tptr) \
((void *)((tptr).v & ~__tagptr_mask(tptr)))
#define tagptr_unfold_tags(tptr) \
((tptr).v & __tagptr_mask(tptr))
/* operations for the tagger pointer */
#define tagptr_eq(_tptr1, _tptr2) ({ \
typeof(_tptr1) tptr1 = (_tptr1); \
typeof(_tptr2) tptr2 = (_tptr2); \
(void)(&tptr1 == &tptr2); \
(tptr1).v == (tptr2).v; })
/* lock-free CAS operation */
#define tagptr_cmpxchg(_ptptr, _o, _n) ({ \
typeof(_ptptr) ptptr = (_ptptr); \
typeof(_o) o = (_o); \
typeof(_n) n = (_n); \
(void)(&o == &n); \
(void)(&o == ptptr); \
tagptr_init(o, cmpxchg(&ptptr->v, o.v, n.v)); })
/* wrap WRITE_ONCE if atomic update is needed */
#define tagptr_replace_tags(_ptptr, tags) ({ \
typeof(_ptptr) ptptr = (_ptptr); \
*ptptr = tagptr_fold(*ptptr, tagptr_unfold_ptr(*ptptr), tags); \
*ptptr; })
#define tagptr_set_tags(_ptptr, _tags) ({ \
typeof(_ptptr) ptptr = (_ptptr); \
const typeof(_tags) tags = (_tags); \
if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \
__bad_tagptr_tags(); \
ptptr->v |= tags; \
*ptptr; })
#define tagptr_clear_tags(_ptptr, _tags) ({ \
typeof(_ptptr) ptptr = (_ptptr); \
const typeof(_tags) tags = (_tags); \
if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \
__bad_tagptr_tags(); \
ptptr->v &= ~tags; \
*ptptr; })
#endif /* __EROFS_FS_TAGPTR_H */

26
fs/erofs/zdata.c
View file

@ -175,15 +175,6 @@ static void z_erofs_free_pcluster(struct z_erofs_pcluster *pcl)
DBG_BUGON(1);
}
/*
* tagged pointer with 1-bit tag for all compressed pages
* tag 0 - the page is just found with an extra page reference
*/
typedef tagptr1_t compressed_page_t;
#define tag_compressed_page_justfound(page) \
tagptr_fold(compressed_page_t, page, 1)
static struct workqueue_struct *z_erofs_workqueue __read_mostly;
void z_erofs_exit_zip_subsystem(void)
@ -319,7 +310,7 @@ static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
for (i = 0; i < pcl->pclusterpages; ++i) {
struct page *page;
compressed_page_t t;
void *t; /* mark pages just found for debugging */
struct page *newpage = NULL;
/* the compressed page was loaded before */
@ -329,7 +320,7 @@ static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
page = find_get_page(mc, pcl->obj.index + i);
if (page) {
t = tag_compressed_page_justfound(page);
t = (void *)((unsigned long)page | 1);
} else {
/* I/O is needed, no possible to decompress directly */
standalone = false;
@ -345,11 +336,10 @@ static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
if (!newpage)
continue;
set_page_private(newpage, Z_EROFS_PREALLOCATED_PAGE);
t = tag_compressed_page_justfound(newpage);
t = (void *)((unsigned long)newpage | 1);
}
if (!cmpxchg_relaxed(&pcl->compressed_bvecs[i].page, NULL,
tagptr_cast_ptr(t)))
if (!cmpxchg_relaxed(&pcl->compressed_bvecs[i].page, NULL, t))
continue;
if (page)
@ -1192,8 +1182,6 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
struct address_space *mapping;
struct page *oldpage, *page;
compressed_page_t t;
int justfound;
repeat:
@ -1203,10 +1191,8 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
if (!page)
goto out_allocpage;
/* process the target tagged pointer */
t = tagptr_init(compressed_page_t, page);
justfound = tagptr_unfold_tags(t);
page = tagptr_unfold_ptr(t);
justfound = (unsigned long)page & 1UL;
page = (struct page *)((unsigned long)page & ~1UL);
/*
* preallocated cached pages, which is used to avoid direct reclaim

1
fs/erofs/zdata.h
View file

@ -7,7 +7,6 @@
#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