netdevsim: Avoid allocation warnings triggered from user space

We need to suppress warnings from sily map sizes. Also switch
from GFP_USER to GFP_KERNEL_ACCOUNT, I'm pretty sure I misunderstood
the flags when writing this code.

Fixes: 395cacb5 ("netdevsim: bpf: support fake map offload")
Reported-by: syzbot+ad24705d3fd6463b18c6@syzkaller.appspotmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220726213605.154204-1-kuba@kernel.org

drivers/net/netdevsim/bpf.c

@@ -351,10 +351,12 @@ nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
 {
 	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
 
-	nmap->entry[idx].key = kmalloc(offmap->map.key_size, GFP_USER);
+	nmap->entry[idx].key = kmalloc(offmap->map.key_size,
+				       GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
 	if (!nmap->entry[idx].key)
 		return -ENOMEM;
-	nmap->entry[idx].value = kmalloc(offmap->map.value_size, GFP_USER);
+	nmap->entry[idx].value = kmalloc(offmap->map.value_size,
+					 GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
 	if (!nmap->entry[idx].value) {
 		kfree(nmap->entry[idx].key);
 		nmap->entry[idx].key = NULL;
@@ -496,7 +498,7 @@ nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
 	if (offmap->map.map_flags)
 		return -EINVAL;
 
-	nmap = kzalloc(sizeof(*nmap), GFP_USER);
+	nmap = kzalloc(sizeof(*nmap), GFP_KERNEL_ACCOUNT);
 	if (!nmap)
 		return -ENOMEM;