[PATCH 12/14] fs: implement kernel_read using __kernel_read
From: Christoph Hellwig <hch@lst.de>
Date: 2020-05-28 05:41:23
Also in:
linux-fsdevel, lkml, netfilter-devel
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
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 <hch@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 bd12af8a895c8..4e19152a7efe0 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c@@ -453,15 +453,12 @@ 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