netlink: use vzalloc()

PATCH In review Stephen Hemminger 3 participants 3 messages Dec 21, 2011

Subsystems (2)

Networking Network drivers

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Stephen Hemminger

author

2011-12-21 21:49 UTC #0 lore raw

PATCH 2/3 netlink: use vzalloc()

The netlink pid hash can be allocated using vzalloc() rather than direct access to get_free_pages. It is also safe for nl_pid_hash_zalloc to use GFP_KERNEL since it is only called from netlink_proto_init and nl_pid_hash_rehash. The former is already allocating table with GFP_KERNEL, and the latter is called from netlink_insert() which already could sleep in netlink_table_grab()

Signed-off-by Stephen Hemminger <[email protected]>

net/netlink/af_netlink.c +3 -5

@@ -251,11 +251,9 @@ found:
 static struct hlist_head *nl_pid_hash_zalloc(size_t size)
 {
 	if (size <= PAGE_SIZE)
-		return kzalloc(size, GFP_ATOMIC);
+		return kzalloc(size, GFP_KERNEL);
 	else
-		return (struct hlist_head *)
-			__get_free_pages(GFP_ATOMIC | __GFP_ZERO,
-					 get_order(size));
+		return vzalloc(size);
 }
 
 static void nl_pid_hash_free(struct hlist_head *table, size_t size)

@@ -263,7 +261,7 @@ static void nl_pid_hash_free(struct hlis
 	if (size <= PAGE_SIZE)
 		kfree(table);
 	else
-		free_pages((unsigned long)table, get_order(size));
+		vfree(table);
 }
 
 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)

Eric Dumazet

2011-12-21 22:12 UTC #1 lore raw

Quoted 7 lines · Stephen Hemminger

The netlink pid hash can be allocated using vzalloc() rather than direct access to get_free_pages. It is also safe for nl_pid_hash_zalloc to use GFP_KERNEL since it is only called from netlink_proto_init and nl_pid_hash_rehash. The former is already allocating table with GFP_KERNEL, and the latter is called from netlink_insert() which already could sleep in netlink_table_grab()

But netlink_table_grab() returns with write_lock_irq(&nl_table_lock);

So we are not allowed to sleep in a netlink_table_grab()/netlink_table_ungrab() section .

David Miller

maintainer

2011-12-21 23:00 UTC #2 lore raw

From: Eric Dumazet <[email protected]>
Date: Wed, 21 Dec 2011 23:12:31 +0100

Quoted 10 lines · Stephen Hemminger

Quoted 7 lines
The netlink pid hash can be allocated using vzalloc() rather than direct access to get_free_pages. It is also safe for nl_pid_hash_zalloc to use GFP_KERNEL since it is only called from netlink_proto_init and nl_pid_hash_rehash. The former is already allocating table with GFP_KERNEL, and the latter is called from netlink_insert() which already could sleep in netlink_table_grab()

Quoted 4 lines

But netlink_table_grab() returns with write_lock_irq(&nl_table_lock);
So we are not allowed to sleep in a netlink_table_grab()/netlink_table_ungrab() section .

Right.