[openib-general] question: ib_umem page_size

[Roland Dreier]

 > > It gives the page size for the user memory described by the struct.
 > > The idea was that if/when someone tries to optimize for huge pages,
 > > then the low-level driver can know that a region is using huge pages
 > > without having to walk through the page list and search for the
 > > minimum physically contiguous size.
 > 
 > Hmm, mthca_reg_user_mr seems to do:
 > 
 > len = sg_dma_len(&chunk->page_list[j]) >> shift
 > 
 > which means that dma_len must be a multiple of page size.
 > 
 > Is this intentional?

Yes, it's intentional I think.  I'm probably missing something, but
the upper layer has just told mthca_reg_user_mr() that the page size
for this region is (1<<shift) -- why shouldn't mthca assume that the
region is made up of chunks that are a multiple of the page size?

 - R.