Hi,

On Fri, Sep 23, 2011 at 1:50 PM, Andrea Gasparini [off-list ref] wrote:

Hi,
I'm having some problem understanding how mmap really works.

I have a (dummy) driver that allocate some memory (4k), and gives it to a
userspace through mmap() - the usual remap_pfn_pages found in every
example.

The userspace can read the memory correctly, but can't write to it. (though
it maps with PROT_WRITE)
As the manpage says: PROT_WRITE - Pages may be written.

Aerhm. If opened with  O_RDRW and mapped with MAP_SHARED it works as expected :)

Sorry for the silly question.
Bye!
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- Andrea Gasparini -
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