linux/mm/folio-compat.c
Baolin Wang be2d575638 mm: change to return bool for folio_isolate_lru()
Patch series "Change the return value for page isolation functions", v3.

Now the page isolation functions did not return a boolean to indicate
success or not, instead it will return a negative error when failed
to isolate a page. So below code used in most places seem a boolean
success/failure thing, which can confuse people whether the isolation
is successful.

if (folio_isolate_lru(folio))
        continue;

Moreover the page isolation functions only return 0 or -EBUSY, and
most users did not care about the negative error except for few users,
thus we can convert all page isolation functions to return a boolean
value, which can remove the confusion to make code more clear.

No functional changes intended in this patch series.


This patch (of 4):

Now the folio_isolate_lru() did not return a boolean value to indicate
isolation success or not, however below code checking the return value can
make people think that it was a boolean success/failure thing, which makes
people easy to make mistakes (see the fix patch[1]).

if (folio_isolate_lru(folio))
	continue;

Thus it's better to check the negative error value expilictly returned by
folio_isolate_lru(), which makes code more clear per Linus's
suggestion[2].  Moreover Matthew suggested we can convert the isolation
functions to return a boolean[3], since most users did not care about the
negative error value, and can also remove the confusing of checking return
value.

So this patch converts the folio_isolate_lru() to return a boolean value,
which means return 'true' to indicate the folio isolation is successful,
and 'false' means a failure to isolation.  Meanwhile changing all users'
logic of checking the isolation state.

No functional changes intended.

[1] https://lore.kernel.org/all/20230131063206.28820-1-Kuan-Ying.Lee@mediatek.com/T/#u
[2] https://lore.kernel.org/all/CAHk-=wiBrY+O-4=2mrbVyxR+hOqfdJ=Do6xoucfJ9_5az01L4Q@mail.gmail.com/
[3] https://lore.kernel.org/all/Y+sTFqwMNAjDvxw3@casper.infradead.org/

Link: https://lkml.kernel.org/r/cover.1676424378.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/8a4e3679ed4196168efadf7ea36c038f2f7d5aa9.1676424378.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-02-20 12:46:17 -08:00

143 lines
3.3 KiB
C

/*
* Compatibility functions which bloat the callers too much to make inline.
* All of the callers of these functions should be converted to use folios
* eventually.
*/
#include <linux/migrate.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include "internal.h"
struct address_space *page_mapping(struct page *page)
{
return folio_mapping(page_folio(page));
}
EXPORT_SYMBOL(page_mapping);
void unlock_page(struct page *page)
{
return folio_unlock(page_folio(page));
}
EXPORT_SYMBOL(unlock_page);
void end_page_writeback(struct page *page)
{
return folio_end_writeback(page_folio(page));
}
EXPORT_SYMBOL(end_page_writeback);
void wait_on_page_writeback(struct page *page)
{
return folio_wait_writeback(page_folio(page));
}
EXPORT_SYMBOL_GPL(wait_on_page_writeback);
void wait_for_stable_page(struct page *page)
{
return folio_wait_stable(page_folio(page));
}
EXPORT_SYMBOL_GPL(wait_for_stable_page);
void mark_page_accessed(struct page *page)
{
folio_mark_accessed(page_folio(page));
}
EXPORT_SYMBOL(mark_page_accessed);
bool set_page_writeback(struct page *page)
{
return folio_start_writeback(page_folio(page));
}
EXPORT_SYMBOL(set_page_writeback);
bool set_page_dirty(struct page *page)
{
return folio_mark_dirty(page_folio(page));
}
EXPORT_SYMBOL(set_page_dirty);
int __set_page_dirty_nobuffers(struct page *page)
{
return filemap_dirty_folio(page_mapping(page), page_folio(page));
}
EXPORT_SYMBOL(__set_page_dirty_nobuffers);
bool clear_page_dirty_for_io(struct page *page)
{
return folio_clear_dirty_for_io(page_folio(page));
}
EXPORT_SYMBOL(clear_page_dirty_for_io);
bool redirty_page_for_writepage(struct writeback_control *wbc,
struct page *page)
{
return folio_redirty_for_writepage(wbc, page_folio(page));
}
EXPORT_SYMBOL(redirty_page_for_writepage);
void lru_cache_add_inactive_or_unevictable(struct page *page,
struct vm_area_struct *vma)
{
folio_add_lru_vma(page_folio(page), vma);
}
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t index, gfp_t gfp)
{
return filemap_add_folio(mapping, page_folio(page), index, gfp);
}
EXPORT_SYMBOL(add_to_page_cache_lru);
noinline
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
int fgp_flags, gfp_t gfp)
{
struct folio *folio;
folio = __filemap_get_folio(mapping, index, fgp_flags, gfp);
if (!folio || xa_is_value(folio))
return &folio->page;
return folio_file_page(folio, index);
}
EXPORT_SYMBOL(pagecache_get_page);
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index)
{
unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
return pagecache_get_page(mapping, index, fgp_flags,
mapping_gfp_mask(mapping));
}
EXPORT_SYMBOL(grab_cache_page_write_begin);
int isolate_lru_page(struct page *page)
{
bool ret;
if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page"))
return -EBUSY;
ret = folio_isolate_lru((struct folio *)page);
if (ret)
return 0;
return -EBUSY;
}
void putback_lru_page(struct page *page)
{
folio_putback_lru(page_folio(page));
}
#ifdef CONFIG_MMU
void page_add_new_anon_rmap(struct page *page, struct vm_area_struct *vma,
unsigned long address)
{
VM_BUG_ON_PAGE(PageTail(page), page);
return folio_add_new_anon_rmap((struct folio *)page, vma, address);
}
#endif