From: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Sent: Monday, February 1, 2021 9:44 AM > > There is a regular need in the kernel to provide a way to declare having > a dynamically sized set of trailing elements in a structure. Kernel code > should always use "flexible array members"[1] for these cases. The older > style of one-element or zero-length arrays should no longer be used[2]. > > Refactor the code according to the use of a flexible-array member in > struct icmsg_negotiate, instead of a one-element array. > > Also, this helps the ongoing efforts to enable -Warray-bounds and fix the > following warnings: > > drivers/hv/channel_mgmt.c:315:23: warning: array subscript 1 is above array bounds of 'struct ic_version[1]' [-Warray-bounds] > drivers/hv/channel_mgmt.c:316:23: warning: array subscript 1 is above array bounds of 'struct ic_version[1]' [-Warray-bounds] > > [1] https://en.wikipedia.org/wiki/Flexible_array_member > [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays > > Link: https://github.com/KSPP/linux/issues/79 > Link: https://github.com/KSPP/linux/issues/109 > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > --- > include/linux/hyperv.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > index f0d48a368f13..7877746f1077 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -1528,14 +1528,14 @@ struct icmsg_hdr { > #define IC_VERSION_NEGOTIATION_MAX_VER_COUNT 100 > #define ICMSG_HDR (sizeof(struct vmbuspipe_hdr) + sizeof(struct icmsg_hdr)) > #define ICMSG_NEGOTIATE_PKT_SIZE(icframe_vercnt, icmsg_vercnt) \ > - (ICMSG_HDR + offsetof(struct icmsg_negotiate, icversion_data) + \ > + (ICMSG_HDR + sizeof(struct icmsg_negotiate) + \ > (((icframe_vercnt) + (icmsg_vercnt)) * sizeof(struct ic_version))) > > struct icmsg_negotiate { > u16 icframe_vercnt; > u16 icmsg_vercnt; > u32 reserved; > - struct ic_version icversion_data[1]; /* any size array */ > + struct ic_version icversion_data[]; /* any size array */ > } __packed; > > struct shutdown_msg_data { > -- > 2.27.0 Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
