RE: [PATCH 1/3] PCI: hv: use the correct buffer size in new_pcichild_device()

From: KY Srinivasan
Date: Mon Nov 14 2016 - 18:32:02 EST




> -----Original Message-----
> From: Dexuan Cui
> Sent: Wednesday, November 9, 2016 11:18 PM
> To: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; linux-pci@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>;
> Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; Jake Oshins <jakeo@xxxxxxxxxxxxx>; Hadden
> Hoppert <haddenh@xxxxxxxxxxxxx>; Vitaly Kuznetsov
> <vkuznets@xxxxxxxxxx>; jasowang@xxxxxxxxxx; apw@xxxxxxxxxxxxx;
> olaf@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH 1/3] PCI: hv: use the correct buffer size in
> new_pcichild_device()
>
> We don't really need such a big on-stack buffer.
> vmbus_sendpacket() here only uses sizeof(struct pci_child_message).
>
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> CC: Jake Oshins <jakeo@xxxxxxxxxxxxx>
> Cc: KY Srinivasan <kys@xxxxxxxxxxxxx>
> CC: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> CC: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

Thanks Dexuan.

Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

> ---
> drivers/pci/host/pci-hyperv.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index 763ff87..93ed64a 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -1271,9 +1271,9 @@ static struct hv_pci_dev
> *new_pcichild_device(struct hv_pcibus_device *hbus,
> struct hv_pci_dev *hpdev;
> struct pci_child_message *res_req;
> struct q_res_req_compl comp_pkt;
> - union {
> - struct pci_packet init_packet;
> - u8 buffer[0x100];
> + struct {
> + struct pci_packet init_packet;
> + u8 buffer[sizeof(struct pci_child_message)];
> } pkt;
> unsigned long flags;
> int ret;
> --
> 2.7.4