PCI: hv: Annotate struct hv_dr_state with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct hv_dr_state.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Link: https://lore.kernel.org/linux-pci/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Reviewed-by: "Gustavo A. R. Silva" <[email protected]>
Acked-by: Wei Liu <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Dexuan Cui <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Krzysztof Wilczyński <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: [email protected]
Cc: [email protected]

Author: kees

drivers/pci/controller/pci-hyperv.c

@@ -545,7 +545,7 @@ struct hv_pcidev_description {
 struct hv_dr_state {
 	struct list_head list_entry;
 	u32 device_count;
-	struct hv_pcidev_description func[];
+	struct hv_pcidev_description func[] __counted_by(device_count);
 };
 
 struct hv_pci_dev {