Messages in this thread | | | Subject | Re: m(un)map kmalloc buffers to userspace | From | Marc Gonzalez <> | Date | Wed, 9 Dec 2015 15:07:50 +0100 |
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On 09/12/2015 14:55, Michal Hocko wrote: > On Tue 08-12-15 18:25:31, Sebastian Frias wrote: >> Hi, >> >> We are porting a driver from Linux 3.4.39+ to 4.1.13+, CPU is Cortex-A9. >> >> The driver maps kmalloc'ed memory to user space. > > This sounds like a terrible idea to me. Why don't you simply use the > page allocator directly? Try to imagine what would happen if you mmaped > a kmalloc with a size which is not page aligned? mmaped memory uses > whole page granularity.
According to the source code, this kernel module calls
kmalloc(1 << 17, GFP_KERNEL | __GFP_REPEAT);
I suppose kmalloc() would return page-aligned memory?
(Note: the kernel module was originally written for 2.4 and was updated inconsistently over the years.)
Regards.
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