unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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erofs: insert to managed cache after adding to pcl

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Previously, it could be some concern to call add_to_page_cache_lru()
with page->mapping == Z_EROFS_MAPPING_STAGING (!= NULL).

In contrast, page->private is used instead now, so partially revert
commit 5ddcee1f3a ("erofs: get rid of __stagingpage_alloc helper")
with some adaption for simplicity.

Link: https://lore.kernel.org/r/20201208095834.3133565-2-hsiangkao@redhat.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
This commit is contained in:
Gao Xiang 2020-12-08 17:58:33 +08:00
parent 6aaa7b0664
commit bf225074ff
1 changed files with 9 additions and 17 deletions
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26
fs/erofs/zdata.c
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@ -1065,29 +1065,21 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
put_page(page);
out_allocpage:
page = erofs_allocpage(pagepool, gfp | __GFP_NOFAIL);
if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
/* turn into temporary page if fails */
set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
tocache = false;
}
if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {
if (tocache) {
/* since it added to managed cache successfully */
unlock_page(page);
put_page(page);
} else {
list_add(&page->lru, pagepool);
}
list_add(&page->lru, pagepool);
cond_resched();
goto repeat;
}
if (tocache) {
attach_page_private(page, pcl);
/* drop a ref added by allocpage (then we have 2 refs here) */
put_page(page);
if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
/* turn into temporary page if fails (1 ref) */
set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
goto out;
}
attach_page_private(page, pcl);
/* drop a refcount added by allocpage (then we have 2 refs here) */
put_page(page);
out: /* the only exit (for tracing and debugging) */
return page;
}