IRQ masking and unmasking

code for the network device drivers and at base environment interrupt management (OSKit version 990722), I have noticed (I can be wrong) that the source IRQ is still masked in the PIC when do_bottom_half code is executed. Is this intentional? May it cause some problem when burst of messages are received? This is important for me, as I must make the assumption that packet loss is a rare event (in a very small LAN, of course). If I have misanderstood your code, please excuse me :-)