fs: implement kernel_read using __kernel_read (6209dd91) · Commits · 戴 / test

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

+5 −8

Original line number	Diff line number	Diff line
		@@ -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);

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