> On Mon, May 12, 2014 at 3:51 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Monday 12 May 2014 10:19:55 Richard Lee wrote: >> For the IO mapping, for the same physical address space maybe >> mapped more than one time, for example, in some SoCs: >> 0x20000000 ~ 0x20001000: are global control IO physical map, >> and this range space will be used by many drivers. >> And then if each driver will do the same ioremap operation, we >> will waste to much malloc virtual spaces. >> >> This patch add IO mapping space reused support. >> >> Signed-off-by: Richard Lee <superlibj@xxxxxxxxx> > > What happens if the first driver then unmaps the area? > If the first driver will unmap the area, it shouldn't do any thing except decreasing the 'used' counter. Thanks, BRs Richard Lee > Arnd -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>