This is a note to let you know that I've just added the patch titled

Drivers: hv: vmbus: Use cpumask_var_t for on-stack cpu mask

to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the char-misc-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From 25355252607ca288f329ee033f387764883393f6 Mon Sep 17 00:00:00 2001

From: Dexuan Cui decui@microsoft.com Date: Sun, 23 Sep 2018 21:10:44 +0000 Subject: Drivers: hv: vmbus: Use cpumask_var_t for on-stack cpu mask MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

A cpumask structure on the stack can cause a warning with CONFIG_NR_CPUS=8192 (e.g. Ubuntu 16.04 and 18.04 use this):

drivers/hv//channel_mgmt.c: In function ‘init_vp_index’: drivers/hv//channel_mgmt.c:702:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Nowadays it looks most distros enable CONFIG_CPUMASK_OFFSTACK=y, and hence we can work around the warning by using cpumask_var_t.

Signed-off-by: Dexuan Cui decui@microsoft.com Cc: K. Y. Srinivasan kys@microsoft.com Cc: Haiyang Zhang haiyangz@microsoft.com Cc: Stephen Hemminger sthemmin@microsoft.com Cc: Stable@vger.kernel.org Signed-off-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hv/channel_mgmt.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 6f3e6af5e891..6277597d3d58 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -594,16 +594,18 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) bool perf_chn = vmbus_devs[dev_type].perf_device; struct vmbus_channel *primary = channel->primary_channel; int next_node; - struct cpumask available_mask; + cpumask_var_t available_mask; struct cpumask *alloced_mask;

if ((vmbus_proto_version == VERSION_WS2008) || - (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) { + (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) || + !alloc_cpumask_var(&available_mask, GFP_KERNEL)) { /* * Prior to win8, all channel interrupts are * delivered on cpu 0. * Also if the channel is not a performance critical * channel, bind it to cpu 0. + * In case alloc_cpumask_var() fails, bind it to cpu 0. */ channel->numa_node = 0; channel->target_cpu = 0; @@ -641,7 +643,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) cpumask_clear(alloced_mask); }

- cpumask_xor(&available_mask, alloced_mask, + cpumask_xor(available_mask, alloced_mask, cpumask_of_node(primary->numa_node));

cur_cpu = -1; @@ -659,10 +661,10 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) }

while (true) { - cur_cpu = cpumask_next(cur_cpu, &available_mask); + cur_cpu = cpumask_next(cur_cpu, available_mask); if (cur_cpu >= nr_cpu_ids) { cur_cpu = -1; - cpumask_copy(&available_mask, + cpumask_copy(available_mask, cpumask_of_node(primary->numa_node)); continue; } @@ -692,6 +694,8 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)

channel->target_cpu = cur_cpu; channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu); + + free_cpumask_var(available_mask); }

static void vmbus_wait_for_unload(void)