Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
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
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


  parent reply index

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

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git