Re: [PATCH 0/6] enable writing to /proc/pid/mem

[Al Viro]

On Tue, Mar 08, 2011 at 09:15:25PM -0500, Stephen Wilson wrote:

> I think we could also remove the intermediate copy in both mem_read() and
> mem_write() as well, but I think such optimizations could be left for
> follow on patches.

How?  We do copy_.._user() in there; it can trigger page faults and
that's not something you want while holding mmap_sem on some mm.
Looks like a deadlock country...  So we can't do that from inside
access_process_vm() or its analogs, which means buffering in caller.
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