From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Kees Cook <keescook@chromium.org>,
Iurii Zaikin <yzaikin@google.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 06/23] fs: implement kernel_write using __kernel_write
Date: Tue, 7 Jul 2020 19:47:44 +0200 [thread overview]
Message-ID: <20200707174801.4162712-7-hch@lst.de> (raw)
In-Reply-To: <20200707174801.4162712-1-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 8f9fc05990ae8b..5110cd1e6e2771 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:[~2020-07-07 17:49 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 17:47 stop using ->read and ->write for kernel access v3 Christoph Hellwig
2020-07-07 17:47 ` [PATCH 01/23] cachefiles: switch to kernel_write Christoph Hellwig
2020-07-07 17:47 ` [PATCH 02/23] autofs: " Christoph Hellwig
2020-07-07 17:47 ` [PATCH 03/23] bpfilter: " Christoph Hellwig
2020-07-07 17:47 ` [PATCH 04/23] fs: unexport __kernel_write Christoph Hellwig
2020-07-07 17:47 ` [PATCH 05/23] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-07-07 17:47 ` Christoph Hellwig [this message]
2020-07-07 17:47 ` [PATCH 07/23] fs: remove __vfs_write Christoph Hellwig
2020-07-07 17:47 ` [PATCH 08/23] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-07-29 20:50 ` Al Viro
2020-07-30 7:02 ` Christoph Hellwig
2020-07-07 17:47 ` [PATCH 09/23] fs: add a __kernel_read helper Christoph Hellwig
2020-07-07 17:47 ` [PATCH 10/23] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-07-07 17:47 ` [PATCH 11/23] fs: implement kernel_read " Christoph Hellwig
2020-07-07 17:47 ` [PATCH 12/23] fs: remove __vfs_read Christoph Hellwig
2020-07-07 17:47 ` [PATCH 13/23] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
2020-07-07 17:47 ` [PATCH 14/23] seq_file: add seq_read_iter Christoph Hellwig
2020-07-07 17:47 ` [PATCH 16/23] proc: remove a level of indentation in proc_get_inode Christoph Hellwig
2020-07-07 17:47 ` [PATCH 17/23] proc: cleanup the compat vs no compat file ops Christoph Hellwig
2020-07-07 17:47 ` [PATCH 18/23] proc: add a read_iter method to proc proc_ops Christoph Hellwig
2020-07-07 17:47 ` [PATCH 19/23] proc: switch over direct seq_read method calls to seq_read_iter Christoph Hellwig
2020-07-07 17:47 ` [PATCH 20/23] sysctl: Convert to iter interfaces Christoph Hellwig
2020-07-07 17:47 ` [PATCH 21/23] fs: don't allow kernel reads and writes without iter ops Christoph Hellwig
2020-07-07 17:48 ` [PATCH 22/23] fs: default to generic_file_splice_read for files having ->read_iter Christoph Hellwig
2020-07-30 0:05 ` Al Viro
2020-07-30 7:03 ` Christoph Hellwig
2020-07-30 15:08 ` Al Viro
2020-07-30 15:20 ` Christoph Hellwig
2020-07-30 16:17 ` Al Viro
2020-07-30 16:22 ` Al Viro
2020-07-30 16:31 ` Christoph Hellwig
2020-07-07 17:48 ` [PATCH 23/23] fs: don't allow splice read/write without explicit ops Christoph Hellwig
2020-07-07 20:24 ` stop using ->read and ->write for kernel access v3 Linus Torvalds
2020-07-08 6:07 ` Christoph Hellwig
2020-07-07 23:03 ` Stephen Rothwell
[not found] ` <20200707174801.4162712-16-hch@lst.de>
2020-07-10 12:55 ` [PATCH 15/23] seq_file: switch over direct seq_read method calls to seq_read_iter Jon Hunter
2020-07-10 12:58 ` Christoph Hellwig
2020-07-11 6:48 ` Christoph Hellwig
2020-07-11 11:47 ` Jon Hunter
2020-07-17 21:09 ` Thomas Gleixner
2020-07-20 9:33 ` Christoph Hellwig
2020-07-29 20:59 ` Al Viro
2020-07-30 7:10 ` Thomas Gleixner
-- strict thread matches above, loose matches on Subject: below --
2020-07-01 20:09 [RFC] stop using ->read and ->write for kernel access v3 Christoph Hellwig
2020-07-01 20:09 ` [PATCH 06/23] fs: implement kernel_write using __kernel_write Christoph Hellwig
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