diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2013-03-20 13:19:30 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-03-21 13:11:11 -0400 |
| commit | 06ae43f34bcc07a0b6be8bf78a1c895bcd12c839 (patch) | |
| tree | b74fe0c7e9370dfed956a1607dd10282c9ba1096 | |
| parent | f6161aa153581da4a3867a2d1a7caf4be19b6ec9 (diff) | |
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>
| -rw-r--r-- | fs/internal.h | 5 | ||||
| -rw-r--r-- | fs/read_write.c | 25 | ||||
| -rw-r--r-- | fs/splice.c | 4 |
3 files changed, 33 insertions, 1 deletions
diff --git a/fs/internal.h b/fs/internal.h index 507141fceb9..4be78237d89 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -125,3 +125,8 @@ extern int invalidate_inodes(struct super_block *, bool); * dcache.c */ extern struct dentry *__d_alloc(struct super_block *, const struct qstr *); + +/* + * read_write.c + */ +extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *); 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; diff --git a/fs/splice.c b/fs/splice.c index 718bd005638..29e394e49dd 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -31,6 +31,7 @@ #include <linux/security.h> #include <linux/gfp.h> #include <linux/socket.h> +#include "internal.h" /* * Attempt to steal a page from a pipe buffer. This should perhaps go into @@ -1048,9 +1049,10 @@ static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf, { int ret; void *data; + loff_t tmp = sd->pos; data = buf->ops->map(pipe, buf, 0); - ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos); + ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp); buf->ops->unmap(pipe, buf, data); return ret; |