cifs: misc: Use array_size() in if-statement controlling expression

Use array_size() instead of the open-coded version in the controlling
expression of the if statement.

Also, while there, use the preferred form for passing a size of a struct.
The alternative form where struct name is spelled out hurts readability
and introduces an opportunity for a bug when the pointer variable type is
changed but the corresponding sizeof that is passed as argument is not.

This issue was found with the help of Coccinelle and, audited and fixed
manually.

Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 56791a692c8be2a5e2df5799b4055fd528e3ad5c..e44d049142d04054293b749fa55d2a013db03593 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -844,28 +844,26 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
        struct bio_vec *bv = NULL;
 
        if (iov_iter_is_kvec(iter)) {
-               memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
+               memcpy(&ctx->iter, iter, sizeof(*iter));
                ctx->len = count;
                iov_iter_advance(iter, count);
                return 0;
        }
 
-       if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
-               bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
-                                  GFP_KERNEL);
+       if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
+               bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
 
        if (!bv) {
-               bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
+               bv = vmalloc(array_size(max_pages, sizeof(*bv)));
                if (!bv)
                        return -ENOMEM;
        }
 
-       if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
-               pages = kmalloc_array(max_pages, sizeof(struct page *),
-                                     GFP_KERNEL);
+       if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
+               pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
 
        if (!pages) {
-               pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
+               pages = vmalloc(array_size(max_pages, sizeof(*pages)));
                if (!pages) {
                        kvfree(bv);
                        return -ENOMEM;