[PATCH v2 14/14] hv: netvsc: use kvzalloc for device state

[Emerson Busson]

alloc_net_device() allocates the fixed-channel netvsc_device with
kzalloc_obj(). The runtime fragmentation drill reaches this allocation
from netvsc_device_add(): windows-2025 reports an order-7 allocation
failure with about 99 MiB free, while windows-latest stalls at channel
open until the guest timeout.

This object is guest-private control-plane metadata, not DMA backing.
Use kvzalloc_obj() so the allocation can fall back to vmalloc when a
high-order kmalloc cannot be satisfied. Zero initialization is preserved.
The RCU workqueue cleanup uses kvfree() to release either backing.

Rollback trigger: revert if channel setup fails with vmalloc capacity
available or teardown leaves netvsc_device allocations outstanding.

Signed-off-by: Emerson Busson <emersonbusson@xxxxxxxxx>
---
 drivers/net/hyperv/netvsc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0d017f836b9e..8ea7c993baac 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -144,7 +144,7 @@ static void __free_netvsc_device(struct netvsc_device *nvdev)
 		vfree(nvdev->chan_table[i].mrc.slots);
 	}
 
-	kfree(nvdev);
+	kvfree(nvdev);
 }
 
 static void free_netvsc_device(struct work_struct *w)
@@ -171,7 +171,7 @@ static struct netvsc_device *alloc_net_device(void)
 {
 	struct netvsc_device *net_device;
 
-	net_device = kzalloc_obj(struct netvsc_device);
+	net_device = kvzalloc_obj(struct netvsc_device);
 	if (!net_device)
 		return NULL;
 
-- 
2.43.0