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: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/pcmcia/ipwireless/hardware.c

@@ -567,7 +567,8 @@ static struct ipw_rx_packet *pool_allocate(struct ipw_hardware *hw,
 			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

@@ -499,3 +499,8 @@ int ipwireless_ppp_unit_number(struct ipw_network *network)
 
 	return ret;
 }
+
+int ipwireless_ppp_mru(const struct ipw_network *network)
+{
+	return network->mru;
+}

drivers/char/pcmcia/ipwireless/network.h

@@ -48,5 +48,6 @@ void ipwireless_ppp_open(struct ipw_network *net);
 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