From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: Christoph Hellwig <hch@lst.de>,
kent.overstreet@gmail.com, Matthew Wilcox <willy@infradead.org>
Subject: [PATCH v4 17/18] mm/filemap: Rename generic_file_buffered_read to filemap_read
Date: Thu, 21 Jan 2021 04:16:15 +0000 [thread overview]
Message-ID: <20210121041616.3955703-18-willy@infradead.org> (raw)
In-Reply-To: <20210121041616.3955703-1-willy@infradead.org>
From: Christoph Hellwig <hch@lst.de>
Rename generic_file_buffered_read to match the naming of filemap_fault,
also update the written parameter to a more descriptive name and
improve the kerneldoc comment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
---
fs/btrfs/file.c | 2 +-
include/linux/fs.h | 4 ++--
mm/filemap.c | 35 ++++++++++++++++-------------------
3 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 87355a38a6547..1a4913e1fd128 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3633,7 +3633,7 @@ static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return ret;
}
- return generic_file_buffered_read(iocb, to, ret);
+ return filemap_read(iocb, to, ret);
}
const struct file_operations btrfs_file_operations = {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d559d43f2af9..a79f65607236a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2948,8 +2948,8 @@ extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
extern int generic_write_check_limits(struct file *file, loff_t pos,
loff_t *count);
extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
-extern ssize_t generic_file_buffered_read(struct kiocb *iocb,
- struct iov_iter *to, ssize_t already_read);
+ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *to,
+ ssize_t already_read);
extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
diff --git a/mm/filemap.c b/mm/filemap.c
index 5563bfe5e544b..50d87aff0ef86 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2383,23 +2383,20 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
}
/**
- * generic_file_buffered_read - generic file read routine
- * @iocb: the iocb to read
- * @iter: data destination
- * @written: already copied
+ * filemap_read - Read data from the page cache.
+ * @iocb: The iocb to read.
+ * @iter: Destination for the data.
+ * @already_read: Number of bytes already read by the caller.
*
- * This is a generic file read routine, and uses the
- * mapping->a_ops->readpage() function for the actual low-level stuff.
+ * Copies data from the page cache. If the data is not currently present,
+ * uses the readahead and readpage address_space operations to fetch it.
*
- * This is really ugly. But the goto's actually try to clarify some
- * of the logic when it comes to error handling etc.
- *
- * Return:
- * * total number of bytes copied, including those the were already @written
- * * negative error code if nothing was copied
+ * Return: Total number of bytes copied, including those already read by
+ * the caller. If an error happens before any bytes are copied, returns
+ * a negative error number.
*/
-ssize_t generic_file_buffered_read(struct kiocb *iocb,
- struct iov_iter *iter, ssize_t written)
+ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
+ ssize_t already_read)
{
struct file *filp = iocb->ki_filp;
struct file_ra_state *ra = &filp->f_ra;
@@ -2423,7 +2420,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
* can no longer safely return -EIOCBQUEUED. Hence mark
* an async read NOWAIT at that point.
*/
- if ((iocb->ki_flags & IOCB_WAITQ) && written)
+ if ((iocb->ki_flags & IOCB_WAITQ) && already_read)
iocb->ki_flags |= IOCB_NOWAIT;
error = filemap_get_pages(iocb, iter, &pvec);
@@ -2483,7 +2480,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
copied = copy_page_to_iter(page, offset, bytes, iter);
- written += copied;
+ already_read += copied;
iocb->ki_pos += copied;
ra->prev_pos = iocb->ki_pos;
@@ -2500,9 +2497,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
file_accessed(filp);
- return written ? written : error;
+ return already_read ? already_read : error;
}
-EXPORT_SYMBOL_GPL(generic_file_buffered_read);
+EXPORT_SYMBOL_GPL(filemap_read);
/**
* generic_file_read_iter - generic filesystem read routine
@@ -2576,7 +2573,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
goto out;
}
- retval = generic_file_buffered_read(iocb, iter, retval);
+ retval = filemap_read(iocb, iter, retval);
out:
return retval;
}
--
2.29.2
next prev parent reply other threads:[~2021-01-21 4:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 4:15 [PATCH v4 00/18] Refactor generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-21 4:15 ` [PATCH v4 01/18] mm/filemap: Rename generic_file_buffered_read subfunctions Matthew Wilcox (Oracle)
2021-01-21 7:30 ` Christoph Hellwig
2021-01-21 8:23 ` Miaohe Lin
2021-01-21 4:16 ` [PATCH v4 02/18] mm/filemap: Remove dynamically allocated array from filemap_read Matthew Wilcox (Oracle)
2021-01-21 7:31 ` Christoph Hellwig
2021-01-22 6:59 ` Miaohe Lin
2021-01-21 4:16 ` [PATCH v4 03/18] mm/filemap: Convert filemap_get_pages to take a pagevec Matthew Wilcox (Oracle)
2021-01-21 7:31 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 04/18] mm/filemap: Use head pages in generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 05/18] mm/filemap: Pass a sleep state to put_and_wait_on_page_locked Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 06/18] mm/filemap: Support readpage splitting a page Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 07/18] mm/filemap: Inline __wait_on_page_locked_async into caller Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 08/18] mm/filemap: Don't call ->readpage if IOCB_WAITQ is set Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 09/18] mm/filemap: Change filemap_read_page calling conventions Matthew Wilcox (Oracle)
2021-01-21 7:31 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 10/18] mm/filemap: Change filemap_create_page " Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 11/18] mm/filemap: Convert filemap_update_page to return an errno Matthew Wilcox (Oracle)
2021-01-21 7:32 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 12/18] mm/filemap: Move the iocb checks into filemap_update_page Matthew Wilcox (Oracle)
2021-01-21 4:16 ` [PATCH v4 13/18] mm/filemap: Add filemap_range_uptodate Matthew Wilcox (Oracle)
2021-01-21 7:32 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 14/18] mm/filemap: Split filemap_readahead out of filemap_get_pages Matthew Wilcox (Oracle)
2021-01-21 7:33 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 15/18] mm/filemap: Restructure filemap_get_pages Matthew Wilcox (Oracle)
2021-01-21 7:33 ` Christoph Hellwig
2021-01-21 4:16 ` [PATCH v4 16/18] mm/filemap: Don't relock the page after calling readpage Matthew Wilcox (Oracle)
2021-01-21 7:34 ` Christoph Hellwig
2021-01-21 4:16 ` Matthew Wilcox (Oracle) [this message]
2021-01-21 4:16 ` [PATCH v4 18/18] mm/filemap: Simplify generic_file_read_iter Matthew Wilcox (Oracle)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210121041616.3955703-18-willy@infradead.org \
--to=willy@infradead.org \
--cc=hch@lst.de \
--cc=kent.overstreet@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).