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 14/14] fs: don't change the address limit for ->read_iter in __kernel_read
Date: Wed, 24 Jun 2020 18:13:35 +0200 [thread overview]
Message-ID: <20200624161335.1810359-15-hch@lst.de> (raw)
In-Reply-To: <20200624161335.1810359-1-hch@lst.de>
If we read to a file that implements ->read_iter there is no need
to change the address limit if we send a kvec down.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/read_write.c | 40 +++++++++++++++++++++++++---------------
1 file changed, 25 insertions(+), 15 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 1c41c25e548d8c..e7f36b15683049 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -421,7 +421,6 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
- mm_segment_t old_fs = get_fs();
ssize_t ret;
if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))
@@ -431,14 +430,25 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
- set_fs(KERNEL_DS);
- if (file->f_op->read)
+ if (file->f_op->read) {
+ mm_segment_t old_fs = get_fs();
+
+ set_fs(KERNEL_DS);
ret = file->f_op->read(file, (void __user *)buf, count, pos);
- else if (file->f_op->read_iter)
- ret = new_sync_read(file, (void __user *)buf, count, pos);
- else
+ set_fs(old_fs);
+ } else if (file->f_op->read_iter) {
+ struct kvec iov = { .iov_base = buf, .iov_len = count };
+ struct kiocb kiocb;
+ struct iov_iter iter;
+
+ init_sync_kiocb(&kiocb, file);
+ kiocb.ki_pos = *pos;
+ iov_iter_kvec(&iter, READ, &iov, 1, count);
+ ret = file->f_op->read_iter(&kiocb, &iter);
+ *pos = kiocb.ki_pos;
+ } else {
ret = -EINVAL;
- set_fs(old_fs);
+ }
if (ret > 0) {
fsnotify_access(file);
add_rchar(current, ret);
@@ -520,7 +530,14 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count,
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
- if (file->f_op->write_iter) {
+ if (file->f_op->write) {
+ mm_segment_t old_fs = get_fs();
+
+ set_fs(KERNEL_DS);
+ ret = file->f_op->write(file, (__force const char __user *)buf,
+ count, pos);
+ set_fs(old_fs);
+ } else if (file->f_op->write_iter) {
struct kvec iov = { .iov_base = (void *)buf, .iov_len = count };
struct kiocb kiocb;
struct iov_iter iter;
@@ -531,13 +548,6 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count,
ret = file->f_op->write_iter(&kiocb, &iter);
if (ret > 0)
*pos = kiocb.ki_pos;
- } else if (file->f_op->write) {
- mm_segment_t old_fs = get_fs();
-
- set_fs(KERNEL_DS);
- ret = file->f_op->write(file, (__force const char __user *)buf,
- count, pos);
- set_fs(old_fs);
} else {
ret = -EINVAL;
}
--
2.26.2
next prev parent reply other threads:[~2020-06-24 16:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 16:13 clean up kernel_{read,write} & friends v5 Christoph Hellwig
2020-06-24 16:13 ` [PATCH 01/14] cachefiles: switch to kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 02/14] autofs: " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 03/14] bpfilter: " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 04/14] fs: unexport __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 06/14] fs: implement kernel_write using __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 07/14] fs: remove __vfs_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 08/14] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 09/14] fs: add a __kernel_read helper Christoph Hellwig
2020-06-24 16:13 ` [PATCH 10/14] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-06-24 16:13 ` [PATCH 11/14] fs: implement kernel_read " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 12/14] fs: remove __vfs_read Christoph Hellwig
2020-06-24 16:13 ` [PATCH 13/14] fs: implement default_file_splice_read using __kernel_read Christoph Hellwig
[not found] ` <20200701091943.GC3874@shao2-debian>
2020-07-01 12:13 ` [fs] 140402bab8: stress-ng.splice.ops_per_sec -100.0% regression Christoph Hellwig
2020-07-01 20:32 ` Linus Torvalds
2020-06-24 16:13 ` Christoph Hellwig [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-05-28 5:40 clean up kernel_{read,write} & friends v2 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
2020-05-13 6:56 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-13 6:56 ` [PATCH 14/14] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
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