[ofa-general] when to use get_dma_mr, which doesn't take physical buffer list size argument

[Bill N]

Hi,

When to use get_dma_mr() instead of reg_phys_mr()?

Looking at the current implementation of get_dma_mr() for Chelsio and NetEffect driver's, they seem to register all the possible system memory to the device. 4GB for Chelsio & 64GB for Neteffect.

Isn't this a hole in case where system has less memory then the capability of the address bus? (Say - 2GB of physical memory & we register 4GB??)

Is get_dma_mr() used for kernel space ULPs with only SGEs(stag=0) instead of stag based send(), recv()?

Can user get_dma_mr() can reregister lesser size memory? If yes, how?

get_dma_mr() is not equivalent to 
9.2.6.1 Allocate Non-Shared Memory Region STag of iWarp-RDMAC specification?

Regards,
Bill