Messages in this thread | | | Date | Thu, 20 Sep 2012 17:09:45 -0700 | From | Kent Overstreet <> | Subject | Re: [PATCH v2 15/26] block: Add bio_copy_data() |
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On Thu, Sep 20, 2012 at 05:06:32PM -0700, Tejun Heo wrote: > Hello, > > On Mon, Sep 10, 2012 at 05:22:26PM -0700, Kent Overstreet wrote: > > +void bio_copy_data(struct bio *dst, struct bio *src) > > +{ > ... > > + src_p = kmap_atomic(src_bv->bv_page); > > + dst_p = kmap_atomic(dst_bv->bv_page); > > + > > + memcpy(dst_p + dst_bv->bv_offset, > > + src_p + src_bv->bv_offset, > > + bytes); > > + > > + kunmap_atomic(dst_p); > > + kunmap_atomic(src_p); > > Wrap these in preempt_disable/enable() to allow the function to be > called from any context?
I checked the implementation of kmap_atomic(), it already does preempt_disable() so it's safe in process context - if I understand correctly it needs local_irq_save()/restore() to be safe in any context and I figured calling this from irq context is not the norm so that should be the caller's responsibility.
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