From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ian Kent <raven@themaw.net>, David Howells <dhowells@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org,
netfilter-devel@vger.kernel.org
Subject: [PATCH 07/14] fs: implement kernel_write using __kernel_write
Date: Thu, 28 May 2020 07:40:36 +0200 [thread overview]
Message-ID: <20200528054043.621510-8-hch@lst.de> (raw)
In-Reply-To: <20200528054043.621510-1-hch@lst.de>
Consolidate the two in-kernel write helpers to make upcoming changes
easier. The only difference are the missing call to rw_verify_area
in kernel_write, and an access_ok check that doesn't make sense for
kernel buffers to start with.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/read_write.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index f0768313ea010..abb84391cfbc5 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -499,6 +499,7 @@ static ssize_t __vfs_write(struct file *file, const char __user *p,
return -EINVAL;
}
+/* caller is responsible for file_start_write/file_end_write */
ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
{
mm_segment_t old_fs;
@@ -528,16 +529,16 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
ssize_t kernel_write(struct file *file, const void *buf, size_t count,
loff_t *pos)
{
- mm_segment_t old_fs;
- ssize_t res;
+ ssize_t ret;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- /* The cast to a user pointer is valid due to the set_fs() */
- res = vfs_write(file, (__force const char __user *)buf, count, pos);
- set_fs(old_fs);
+ ret = rw_verify_area(WRITE, file, pos, count);
+ if (ret)
+ return ret;
- return res;
+ file_start_write(file);
+ ret = __kernel_write(file, buf, count, pos);
+ file_end_write(file);
+ return ret;
}
EXPORT_SYMBOL(kernel_write);
--
2.26.2
next prev parent reply other threads:[~2020-05-28 5:41 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 5:40 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-28 5:40 ` [PATCH 01/14] cachefiles: switch to kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 02/14] autofs: " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 03/14] bpfilter: " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 04/14] fs: unexport __kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 06/14] fs: remove the call_{read,write}_iter functions Christoph Hellwig
2020-05-28 18:56 ` Al Viro
2020-05-29 5:51 ` Christoph Hellwig
2020-05-28 5:40 ` Christoph Hellwig [this message]
2020-05-28 5:40 ` [PATCH 08/14] fs: remove __vfs_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 09/14] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-05-28 18:43 ` Linus Torvalds
2020-05-29 12:32 ` Christoph Hellwig
2020-05-31 23:59 ` Logan Gunthorpe
2020-05-28 19:00 ` Al Viro
2020-05-29 5:57 ` Christoph Hellwig
2020-05-29 13:37 ` Christoph Hellwig
2020-05-28 5:40 ` [PATCH 10/14] fs: add a __kernel_read helper Christoph Hellwig
2020-05-28 5:40 ` [PATCH 11/14] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-05-28 5:40 ` [PATCH 12/14] fs: implement kernel_read " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 13/14] fs: remove __vfs_read Christoph Hellwig
2020-05-28 5:40 ` [PATCH 14/14] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
2020-05-28 19:03 ` Al Viro
2020-05-28 18:51 ` clean up kernel_{read,write} & friends v2 Linus Torvalds
2020-05-28 18:57 ` Sedat Dilek
2020-05-28 19:22 ` Joe Perches
2020-05-28 19:33 ` Al Viro
2020-05-28 19:44 ` Matthew Wilcox
2020-05-28 20:06 ` Al Viro
2020-05-28 20:14 ` Deucher, Alexander
2020-05-28 20:18 ` Joe Perches
2020-05-28 20:29 ` Dave Airlie
2020-05-28 21:03 ` Joe Perches
2020-05-28 20:17 ` David Howells
2020-05-28 21:20 ` Casey Schaufler
2020-05-29 13:08 ` David Laight
2020-05-29 19:19 ` Linus Torvalds
2020-05-29 22:02 ` Casey Schaufler
2020-05-29 23:12 ` [PATCH] checkpatch/coding-style: Allow 100 column lines Joe Perches
2020-05-30 22:14 ` Andreas Dilger
2020-05-30 23:15 ` Joe Perches
2020-06-05 6:36 ` clean up kernel_{read,write} & friends v2 Philippe Mathieu-Daudé
2020-06-05 15:00 ` Nicolas Pitre
-- strict thread matches above, loose matches on Subject: below --
2020-05-13 6:56 Christoph Hellwig
2020-05-13 6:56 ` [PATCH 07/14] fs: implement kernel_write using __kernel_write Christoph Hellwig
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