On Mon, May 25, 2020 at 11:43:19AM -0500, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct hv_dr_state {
> ...
> struct hv_pcidev_description func[];
> };
>
> struct pci_bus_relations {
> ...
> struct pci_function_description func[];
> } __packed;
>
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
>
> So, replace the following forms:
>
> offsetof(struct hv_dr_state, func) +
> (sizeof(struct hv_pcidev_description) *
> (relations->device_count))
>
> offsetof(struct pci_bus_relations, func) +
> (sizeof(struct pci_function_description) *
> (bus_rel->device_count))
>
> with:
>
> struct_size(dr, func, relations->device_count)
>
> and
>
> struct_size(bus_rel, func, bus_rel->device_count)
>
> respectively.
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> drivers/pci/controller/pci-hyperv.c | 22 ++++++++--------------
> 1 file changed, 8 insertions(+), 14 deletions(-)
Applied to pci/hv, thanks.
Lorenzo
> diff --git a/drivers/pci/controller/pci-hyperv.c
> b/drivers/pci/controller/pci-hyperv.c
> index 892f3a742117a..bf40ff09c99d6 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -2213,10 +2213,8 @@ static void hv_pci_devices_present(struct
> hv_pcibus_device *hbus,
> struct hv_dr_state *dr;
> int i;
>
> - dr = kzalloc(offsetof(struct hv_dr_state, func) +
> - (sizeof(struct hv_pcidev_description) *
> - (relations->device_count)), GFP_NOWAIT);
> -
> + dr = kzalloc(struct_size(dr, func, relations->device_count),
> + GFP_NOWAIT);
> if (!dr)
> return;
>
> @@ -2250,10 +2248,8 @@ static void hv_pci_devices_present2(struct
> hv_pcibus_device *hbus,
> struct hv_dr_state *dr;
> int i;
>
> - dr = kzalloc(offsetof(struct hv_dr_state, func) +
> - (sizeof(struct hv_pcidev_description) *
> - (relations->device_count)), GFP_NOWAIT);
> -
> + dr = kzalloc(struct_size(dr, func, relations->device_count),
> + GFP_NOWAIT);
> if (!dr)
> return;
>
> @@ -2447,9 +2443,8 @@ static void hv_pci_onchannelcallback(void *context)
>
> bus_rel = (struct pci_bus_relations *)buffer;
> if (bytes_recvd <
> - offsetof(struct pci_bus_relations, func) +
> - (sizeof(struct pci_function_description) *
> - (bus_rel->device_count))) {
> + struct_size(bus_rel, func,
> + bus_rel->device_count)) {
> dev_err(&hbus->hdev->device,
> "bus relations too small\n");
> break;
> @@ -2462,9 +2457,8 @@ static void hv_pci_onchannelcallback(void *context)
>
> bus_rel2 = (struct pci_bus_relations2 *)buffer;
> if (bytes_recvd <
> - offsetof(struct pci_bus_relations2, func) +
> - (sizeof(struct pci_function_description2) *
> - (bus_rel2->device_count))) {
> + struct_size(bus_rel2, func,
> + bus_rel2->device_count)) {
> dev_err(&hbus->hdev->device,
> "bus relations v2 too small\n");
> break;
> --
> 2.26.2
>
