From: Matthew Wilcox <willy@infradead.org>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: gfs2@lists.linux.dev
Subject: Re: [bug report] gfs2: Convert gfs2_jhead_process_page() to use a folio
Date: Thu, 12 Oct 2023 16:27:55 +0100 [thread overview]
Message-ID: <ZSgQe27OCfUpmsbS@casper.infradead.org> (raw)
In-Reply-To: <fb027038-46ee-49fa-be1f-28926e7e2387@moroto.mountain>
On Thu, Oct 12, 2023 at 12:43:34PM +0300, Dan Carpenter wrote:
> Hello Matthew Wilcox (Oracle),
>
> The patch 240159077d00: "gfs2: Convert gfs2_jhead_process_page() to
> use a folio" from May 13, 2022 (linux-next), leads to the following
> Smatch static checker warning:
>
> fs/gfs2/lops.c:485 gfs2_jhead_process_page()
> error: 'folio' dereferencing possible ERR_PTR()
>
> fs/gfs2/lops.c
> 469 static void gfs2_jhead_process_page(struct gfs2_jdesc *jd, unsigned long index,
> 470 struct gfs2_log_header_host *head,
> 471 bool *done)
> 472 {
> 473 struct folio *folio;
> 474
> 475 folio = filemap_get_folio(jd->jd_inode->i_mapping, index);
>
> Does filemap_get_folio() need to be checked for errors?
In this specific case, we know that the folio is there and will always
be returned. See the comment on line 484. Can I annotate this call so
that the tool knows this is a special case and doesn't warn about it?
> 476
> 477 folio_wait_locked(folio);
> 478 if (folio_test_error(folio))
> 479 *done = true;
> 480
> 481 if (!*done)
> 482 *done = gfs2_jhead_pg_srch(jd, head, &folio->page);
> 483
> 484 /* filemap_get_folio() and the earlier grab_cache_page() */
> --> 485 folio_put_refs(folio, 2);
> 486 }
>
> regards,
> dan carpenter
next prev parent reply other threads:[~2023-10-12 15:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-12 9:43 [bug report] gfs2: Convert gfs2_jhead_process_page() to use a folio Dan Carpenter
2023-10-12 15:27 ` Matthew Wilcox [this message]
2023-10-13 6:28 ` Dan Carpenter
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