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authorAl Viro <viro@zeniv.linux.org.uk>2013-03-20 13:19:30 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2013-03-21 13:11:11 -0400
commit06ae43f34bcc07a0b6be8bf78a1c895bcd12c839 (patch)
treeb74fe0c7e9370dfed956a1607dd10282c9ba1096 /fs/read_write.c
parentf6161aa153581da4a3867a2d1a7caf4be19b6ec9 (diff)
downloadlinux-06ae43f34bcc07a0b6be8bf78a1c895bcd12c839.tar.gz
Don't bother with redoing rw_verify_area() from default_file_splice_from()
default_file_splice_from() ends up calling vfs_write() (via very convoluted callchain). It's an overkill, since we already have done rw_verify_area() in the caller by the time we call vfs_write() we are under set_fs(KERNEL_DS), so access_ok() is also pointless. Add a new helper (__kernel_write()), use it instead of kernel_write() in there. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index a698eff457f..f7b5a23b804 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -17,6 +17,7 @@
#include <linux/splice.h>
#include <linux/compat.h>
#include "read_write.h"
+#include "internal.h"
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -417,6 +418,30 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
EXPORT_SYMBOL(do_sync_write);
+ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
+{
+ mm_segment_t old_fs;
+ const char __user *p;
+ ssize_t ret;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ p = (__force const char __user *)buf;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ if (file->f_op->write)
+ ret = file->f_op->write(file, p, count, pos);
+ else
+ ret = do_sync_write(file, p, count, pos);
+ set_fs(old_fs);
+ if (ret > 0) {
+ fsnotify_modify(file);
+ add_wchar(current, ret);
+ }
+ inc_syscw(current);
+ return ret;
+}
+
ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;