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jffs2: Use a folio in jffs2_garbage_collect_dnode()

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Call read_cache_folio() instead of read_cache_page() to get the folio
containing the page.  No attempt is made here to support large folios
as I assume that will never be interesting for jffs2.  Includes a switch
from kmap to kmap_local which looks safe.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240814195915.249871-3-willy@infradead.org
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2024-08-14 20:59:13 +01:00 committed by Christian Brauner
parent bcc7d11e6c
commit 2da4c51a66
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 12 additions and 13 deletions
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25
fs/jffs2/gc.c
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@ -1171,7 +1171,7 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
uint32_t alloclen, offset, orig_end, orig_start;
int ret = 0;
unsigned char *comprbuf = NULL, *writebuf;
struct page *page;
struct folio *folio;
unsigned char *pg_ptr;
memset(&ri, 0, sizeof(ri));
@ -1317,25 +1317,25 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
BUG_ON(start > orig_start);
}
/* The rules state that we must obtain the page lock *before* f->sem, so
/* The rules state that we must obtain the folio lock *before* f->sem, so
* drop f->sem temporarily. Since we also hold c->alloc_sem, nothing's
* actually going to *change* so we're safe; we only allow reading.
*
* It is important to note that jffs2_write_begin() will ensure that its
* page is marked Uptodate before allocating space. That means that if we
* end up here trying to GC the *same* page that jffs2_write_begin() is
* trying to write out, read_cache_page() will not deadlock. */
* folio is marked uptodate before allocating space. That means that if we
* end up here trying to GC the *same* folio that jffs2_write_begin() is
* trying to write out, read_cache_folio() will not deadlock. */
mutex_unlock(&f->sem);
page = read_cache_page(inode->i_mapping, start >> PAGE_SHIFT,
folio = read_cache_folio(inode->i_mapping, start >> PAGE_SHIFT,
__jffs2_read_folio, NULL);
if (IS_ERR(page)) {
pr_warn("read_cache_page() returned error: %ld\n",
PTR_ERR(page));
if (IS_ERR(folio)) {
pr_warn("read_cache_folio() returned error: %ld\n",
PTR_ERR(folio));
mutex_lock(&f->sem);
return PTR_ERR(page);
return PTR_ERR(folio);
}
pg_ptr = kmap(page);
pg_ptr = kmap_local_folio(folio, 0);
mutex_lock(&f->sem);
offset = start;
@ -1400,7 +1400,6 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
}
}
kunmap(page);
put_page(page);
folio_release_kmap(folio, pg_ptr);
return ret;
}