diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-05-08 08:54:16 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-07-08 08:27:56 +0200 |
| commit | 61a707c543e2afe3aa7e88f87267c5dafa4b5afa (patch) | |
| tree | 0890bd5d37503f57d3dca76d90a320eda56a802a /fs | |
| parent | 53ad86266bda973b526078227997ca3fcb92c9be (diff) | |
fs: add a __kernel_read helper
This is the counterpart to __kernel_write, and skip the rw_verify_area
call compared to kernel_read.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/read_write.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index 96e8e354f99b..21c9d90a257e 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -430,6 +430,29 @@ ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, return -EINVAL; } +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))) + return -EINVAL; + if (!(file->f_mode & FMODE_CAN_READ)) + return -EINVAL; + + if (count > MAX_RW_COUNT) + count = MAX_RW_COUNT; + set_fs(KERNEL_DS); + ret = __vfs_read(file, (void __user *)buf, count, pos); + set_fs(old_fs); + if (ret > 0) { + fsnotify_access(file); + add_rchar(current, ret); + } + inc_syscr(current); + return ret; +} + ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; |