ipwireless: Preallocate received packet buffers with MRU size

ipwireless: Preallocate received packet buffers with MRU size

Packets are assembled from link size (~300 bytes) up to PPP MRU
(1500 by default). Try to preallocate full size rather than
repeatedly advance buffer size by 256 bytes.

Signed-off-by: David Sterba <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/pcmcia/ipwireless/hardware.c

···
 			spin_unlock_irqrestore(&hw->lock, flags);
 			list_del(&packet->queue);
 		} else {
-			static int min_capacity = 256;
+			const int min_capacity =
+				ipwireless_ppp_mru(hw->network + 2);
 			int new_capacity;
 
 			spin_unlock_irqrestore(&hw->lock, flags);

drivers/char/pcmcia/ipwireless/network.c

···
 
 	return ret;
 }
+
+int ipwireless_ppp_mru(const struct ipw_network *network)
+{
+	return network->mru;
+}

drivers/char/pcmcia/ipwireless/network.h

···
 void ipwireless_ppp_close(struct ipw_network *net);
 int ipwireless_ppp_channel_index(struct ipw_network *net);
 int ipwireless_ppp_unit_number(struct ipw_network *net);
+int ipwireless_ppp_mru(const struct ipw_network *net);
 
 #endif