From: Matthew Wilcox (Oracle) Date: Fri, 30 Apr 2021 05:55:29 +0000 (-0700) Subject: mm/filemap: drop check for truncated page after I/O X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=79e3094c53c56d0d4da23f578de271e7602ba5ed;p=linux.git mm/filemap: drop check for truncated page after I/O If the I/O completed successfully, the page will remain Uptodate, even if it is subsequently truncated. If the I/O completed with an error, this check would cause us to retry the I/O if the page were truncated before we woke up. There is no need to retry the I/O; the I/O to fill the page failed, so we can legitimately just return -EIO. This code was originally added by commit 56f0d5fe6851 ("[PATCH] readpage-vs-invalidate fix") in 2005 (this commit ID is from the linux-fullhistory tree; it is also commit ba1f08f14b52 in tglx-history). At the time, truncate_complete_page() called ClearPageUptodate(), and so this was fixing a real bug. In 2008, commit 84209e02de48 ("mm: dont clear PG_uptodate on truncate/invalidate") removed the call to ClearPageUptodate, and this check has been unnecessary ever since. It doesn't do any real harm, but there's no need to keep it. Link: https://lkml.kernel.org/r/20210303222547.1056428-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: William Kucharski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/filemap.c b/mm/filemap.c index 84e7f3c7d6675..9620696f880cd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2348,8 +2348,6 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, return error; if (PageUptodate(page)) return 0; - if (!page->mapping) /* page truncated */ - return AOP_TRUNCATED_PAGE; shrink_readahead_size_eio(&file->f_ra); return -EIO; }