From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 05/13] mm: simplify generic_file_buffered_read_no_cached_page
Date: Sat, 31 Oct 2020 09:59:56 +0100 [thread overview]
Message-ID: <20201031090004.452516-6-hch@lst.de> (raw)
In-Reply-To: <20201031090004.452516-1-hch@lst.de>
Return an errno and add a new by reference argument for the allocated
page, which allows to cleanup the error unwindining in the function
and the caller. Also rename the function to filemap_new_page which is
both shorter and more descriptive.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
mm/filemap.c | 53 ++++++++++++++++------------------------------------
1 file changed, 16 insertions(+), 37 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 5cdf8090d4e12c..9e1cc18afe1134 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2300,41 +2300,27 @@ static int filemap_make_page_uptodate(struct kiocb *iocb, struct iov_iter *iter,
return error;
}
-static struct page *
-generic_file_buffered_read_no_cached_page(struct kiocb *iocb,
- struct iov_iter *iter)
+static int filemap_new_page(struct kiocb *iocb, struct iov_iter *iter,
+ struct page **page)
{
- struct file *filp = iocb->ki_filp;
- struct address_space *mapping = filp->f_mapping;
+ struct address_space *mapping = iocb->ki_filp->f_mapping;
+ gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;
- struct page *page;
int error;
if (iocb->ki_flags & IOCB_NOIO)
- return ERR_PTR(-EAGAIN);
+ return -EAGAIN;
- /*
- * Ok, it wasn't cached, so we need to create a new
- * page..
- */
- page = page_cache_alloc(mapping);
+ *page = page_cache_alloc(mapping);
if (!page)
- return ERR_PTR(-ENOMEM);
-
- error = add_to_page_cache_lru(page, mapping, index,
- mapping_gfp_constraint(mapping, GFP_KERNEL));
+ return -ENOMEM;
+ error = add_to_page_cache_lru(*page, mapping, index, gfp);
if (error) {
- put_page(page);
- return error != -EEXIST ? ERR_PTR(error) : NULL;
+ put_page(*page);
+ return error;
}
- error = filemap_readpage(iocb, page);
- if (error) {
- if (error == AOP_TRUNCATED_PAGE)
- return NULL;
- return ERR_PTR(error);
- }
- return page;
+ return filemap_readpage(iocb, *page);
}
static int generic_file_buffered_read_get_pages(struct kiocb *iocb,
@@ -2366,18 +2352,14 @@ static int generic_file_buffered_read_get_pages(struct kiocb *iocb,
nr_got = find_get_pages_contig(mapping, index, nr, pages);
if (nr_got)
goto got_pages;
-
- pages[0] = generic_file_buffered_read_no_cached_page(iocb, iter);
- err = PTR_ERR_OR_ZERO(pages[0]);
- if (!IS_ERR_OR_NULL(pages[0]))
+ err = filemap_new_page(iocb, iter, &pages[0]);
+ if (!err)
nr_got = 1;
got_pages:
for (i = 0; i < nr_got; i++) {
err = filemap_make_page_uptodate(iocb, iter, pages[i],
index + i, i == 0);
if (err) {
- if (err == AOP_TRUNCATED_PAGE)
- err = 0;
for (j = i + 1; j < nr_got; j++)
put_page(pages[j]);
nr_got = i;
@@ -2387,12 +2369,9 @@ static int generic_file_buffered_read_get_pages(struct kiocb *iocb,
if (likely(nr_got))
return nr_got;
- if (err)
- return err;
- /*
- * No pages and no error means we raced and should retry:
- */
- goto find_page;
+ if (err == -EEXIST || err == AOP_TRUNCATED_PAGE)
+ goto find_page;
+ return err;
}
/**
--
2.28.0
next prev parent reply other threads:[~2020-10-31 9:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-31 8:59 clean up the generic pagecache read helpers Christoph Hellwig
2020-10-31 8:59 ` [PATCH 01/13] mm: simplify generic_file_buffered_read_readpage Christoph Hellwig
2020-10-31 8:59 ` [PATCH 02/13] mm: simplify generic_file_buffered_read_pagenotuptodate Christoph Hellwig
2020-10-31 8:59 ` [PATCH 03/13] mm: lift the nowait checks into generic_file_buffered_read_pagenotuptodate Christoph Hellwig
2020-10-31 8:59 ` [PATCH 04/13] mm: handle readahead in generic_file_buffered_read_pagenotuptodate Christoph Hellwig
2020-10-31 17:06 ` Matthew Wilcox
2020-11-01 10:31 ` Christoph Hellwig
2020-11-01 10:49 ` Matthew Wilcox
2020-11-01 10:51 ` Christoph Hellwig
2020-11-01 10:51 ` Christoph Hellwig
2020-11-01 11:04 ` Matthew Wilcox
2020-11-01 11:52 ` Christoph Hellwig
2020-11-01 14:55 ` Matthew Wilcox
2020-11-02 8:18 ` Christoph Hellwig
2020-10-31 8:59 ` Christoph Hellwig [this message]
2020-10-31 16:20 ` [PATCH 05/13] mm: simplify generic_file_buffered_read_no_cached_page Matthew Wilcox
2020-10-31 16:28 ` Matthew Wilcox
2020-11-01 10:29 ` Christoph Hellwig
2020-10-31 8:59 ` [PATCH 06/13] mm: factor out a filemap_find_get_pages helper Christoph Hellwig
2020-10-31 8:59 ` [PATCH 07/13] mm: refactor generic_file_buffered_read_get_pages Christoph Hellwig
2020-11-01 11:18 ` Matthew Wilcox
2020-10-31 8:59 ` [PATCH 08/13] mm: move putting the page on error out of filemap_readpage Christoph Hellwig
2020-10-31 9:00 ` [PATCH 09/13] mm: move putting the page on error out of filemap_make_page_uptodate Christoph Hellwig
2020-10-31 9:00 ` [PATCH 10/13] mm: open code readahead in filemap_new_page Christoph Hellwig
2020-11-01 11:20 ` Matthew Wilcox
2020-10-31 9:00 ` [PATCH 11/13] mm: streamline the partially uptodate checks in filemap_make_page_uptodate Christoph Hellwig
2020-11-01 11:23 ` Matthew Wilcox
2020-10-31 9:00 ` [PATCH 12/13] mm: rename generic_file_buffered_read to filemap_read Christoph Hellwig
2020-10-31 9:00 ` [PATCH 13/13] mm: simplify generic_file_read_iter Christoph Hellwig
2020-10-31 15:42 ` clean up the generic pagecache read helpers Matthew Wilcox
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