linux-kernel - [PATCH 02/11] fs: factor out a set_fmode_can_read

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Date:   Wed, 24 Jun 2020 18:28:52 +0200
From:   Christoph Hellwig <hch@....de>
To:     Al Viro <viro@...iv.linux.org.uk>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Luis Chamberlain <mcgrof@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Iurii Zaikin <yzaikin@...gle.com>,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 02/11] fs: factor out a set_fmode_can_read_write helper

Add a helper to set the FMODE_CAN_READ and FMODE_CAN_WRITE logic
instead of duplicating it in two places.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/file_table.c |  7 +------
 fs/internal.h   | 10 ++++++++++
 fs/open.c       |  8 +-------
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 656647f9575a7c..646b83f07a9589 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -199,16 +199,11 @@ static struct file *alloc_file(const struct path *path, int flags,
 	file->f_mapping = path->dentry->d_inode->i_mapping;
 	file->f_wb_err = filemap_sample_wb_err(file->f_mapping);
 	file->f_sb_err = file_sample_sb_err(file);
-	if ((file->f_mode & FMODE_READ) &&
-	     likely(fop->read || fop->read_iter))
-		file->f_mode |= FMODE_CAN_READ;
-	if ((file->f_mode & FMODE_WRITE) &&
-	     likely(fop->write || fop->write_iter))
-		file->f_mode |= FMODE_CAN_WRITE;
 	file->f_mode |= FMODE_OPENED;
 	file->f_op = fop;
 	if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
 		i_readcount_inc(path->dentry->d_inode);
+	set_fmode_can_read_write(file);
 	return file;
 }
 
diff --git a/fs/internal.h b/fs/internal.h
index 9b863a7bd70892..242f2845b3428b 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -185,3 +185,13 @@ int sb_init_dio_done_wq(struct super_block *sb);
  */
 int do_statx(int dfd, const char __user *filename, unsigned flags,
 	     unsigned int mask, struct statx __user *buffer);
+
+static inline void set_fmode_can_read_write(struct file *f)
+{
+	if ((f->f_mode & FMODE_READ) &&
+	    (f->f_op->read || f->f_op->read_iter))
+		f->f_mode |= FMODE_CAN_READ;
+	if ((f->f_mode & FMODE_WRITE) &&
+	    (f->f_op->write || f->f_op->write_iter))
+		f->f_mode |= FMODE_CAN_WRITE;
+}
diff --git a/fs/open.c b/fs/open.c
index 6cd48a61cda3b9..01f2de93c91710 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -832,13 +832,7 @@ static int do_dentry_open(struct file *f,
 	f->f_mode |= FMODE_OPENED;
 	if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
 		i_readcount_inc(inode);
-	if ((f->f_mode & FMODE_READ) &&
-	     likely(f->f_op->read || f->f_op->read_iter))
-		f->f_mode |= FMODE_CAN_READ;
-	if ((f->f_mode & FMODE_WRITE) &&
-	     likely(f->f_op->write || f->f_op->write_iter))
-		f->f_mode |= FMODE_CAN_WRITE;
-
+	set_fmode_can_read_write(f);
 	f->f_write_hint = WRITE_LIFE_NOT_SET;
 	f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
-- 
2.26.2