configfs: fix memleak in configfs_release_bin_file

mainline inclusion
from mainline-5.14
commit 3c252b08
category: bugfix
bugzilla: 171902 https://gitee.com/openeuler/kernel/issues/I4DDEL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3c252b087de08d3cb32468b54a158bd7ad0ae2f7

-------------------------------------------------

When reading binary attributes in progress, buffer->bin_buffer is setup in
configfs_read_bin_file() but never freed.

Fixes: 03607ace ("configfs: implement binary attributes")
Signed-off-by: NChung-Chiang Cheng <cccheng@synology.com>
[hch: move the vfree rather than duplicating it]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBaokun Li <libaokun1@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/configfs/file.c

@@ -482,12 +482,12 @@ static int configfs_release_bin_file(struct inode *inode, struct file *file)
 					buffer->bin_buffer_size);
 		}
 		up_read(&frag->frag_sem);
-		/* vfree on NULL is safe */
+	}
+
 	vfree(buffer->bin_buffer);
 	buffer->bin_buffer = NULL;
 	buffer->bin_buffer_size = 0;
 	buffer->needs_read_fill = 1;
-	}
 
 	configfs_release(inode, file);
 	return 0;