staging: vc04_services: shut up out-of-range warning

The comparison against SIZE_MAX produces a harmless warning on 64-bit
architectures:

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:185:16: error: result of comparison of constant 419244183493398898 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        if (num_pages > (SIZE_MAX - sizeof(struct pagelist) -
            ~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Shut up that warning by adding a cast to a longer type.

Fixes: ca641bae6da9 ("staging: vc04_services: prevent integer overflow in create_pagelist()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210927113702.3866843-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index b25369a134525e0c1bf03c45a00fe3b82f964824..967f10b9582a826c8d0101e273f710a1e46bba71 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -182,7 +182,7 @@ create_pagelist(char *buf, char __user *ubuf,
                offset = (uintptr_t)ubuf & (PAGE_SIZE - 1);
        num_pages = DIV_ROUND_UP(count + offset, PAGE_SIZE);
 
-       if (num_pages > (SIZE_MAX - sizeof(struct pagelist) -
+       if ((size_t)num_pages > (SIZE_MAX - sizeof(struct pagelist) -
                         sizeof(struct vchiq_pagelist_info)) /
                        (sizeof(u32) + sizeof(pages[0]) +
                         sizeof(struct scatterlist)))