Re: [PATCH 10 of 20] ipath - support for userspace apps using core driver

From: Roland Dreier
Date: Thu Mar 16 2006 - 00:52:11 EST


Andrew> Someone left PG_private set on this page (!)

How does PG_private get set? Could doing a > 1 page kmalloc set it
(because we end up with a compound page)?

Andrew> You need to decide who "owns" these pages. Once that's
Andrew> decided, it tells you who should release them.

[... really good guide to mapping pages into userspace snipped ...]

How about the case where one wants to map pages from
dma_alloc_coherent() into userspace? It seems one should do
get_page() in .nopage, and then the driver can do dma_free_coherent()
when the vma is released.

Or maybe it's just simpler to use vm_insert_page() in the .mmap method
and not try to be fancy with .nopage?

- R.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/