Consolidate the two in-kernel read helpers to make upcoming changes
easier.  The only difference are the missing call to rw_verify_area
in kernel_read, and an access_ok check that doesn't make sense for
kernel buffers to start with.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 fs/read_write.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index cc8e0b4f3cd697..a0a0b5d1d9249c 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -455,15 +455,12 @@ ssize_t __kernel_read(struct file *file, void *buf, 
size_t count, loff_t *pos)
 
 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 {
-       mm_segment_t old_fs;
-       ssize_t result;
+       ssize_t ret;
 
-       old_fs = get_fs();
-       set_fs(KERNEL_DS);
-       /* The cast to a user pointer is valid due to the set_fs() */
-       result = vfs_read(file, (void __user *)buf, count, pos);
-       set_fs(old_fs);
-       return result;
+       ret = rw_verify_area(READ, file, pos, count);
+       if (ret)
+               return ret;
+       return __kernel_read(file, buf, count, pos);
 }
 EXPORT_SYMBOL(kernel_read);
 
-- 
2.26.2

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