From: David Miller <davem@davemloft.net>
Subject: Re: sk_lock: inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W}
 usage
Date: Thu, 09 Jul 2009 17:13:55 -0700 (PDT)
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From: Wu Fengguang <fengguang.wu@intel.com>
Date: Thu, 9 Jul 2009 21:17:46 +0800

> @@ -2100,7 +2100,8 @@ void tcp_send_fin(struct sock *sk)
>  	} else {
>  		/* Socket is locked, keep trying until memory is available. */
>  		for (;;) {
> -			skb = alloc_skb_fclone(MAX_TCP_HEADER, GFP_KERNEL);
> +			skb = alloc_skb_fclone(MAX_TCP_HEADER,
> +					       sk->sk_allocation);
>  			if (skb)
>  				break;
>  			yield();

I think this specific case needs more thinking.

If the allocation fails, and it's GFP_ATOMIC, we are going to yield()
(which sleeps) and loop endlessly waiting for the allocation to
succeed.