Messages in this thread | | | Subject | Re: Re: Re: Re: Re: [PATCH] RDMA/siw: Fix compiler warnings on 32-bit due to u64/pointer abuse | From | "Bernard Metzler" <> | Date | Mon, 19 Aug 2019 16:29:11 +0000 |
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-----"Jason Gunthorpe" <jgg@ziepe.ca> wrote: -----
>To: "Bernard Metzler" <BMT@zurich.ibm.com> >From: "Jason Gunthorpe" <jgg@ziepe.ca> >Date: 08/19/2019 06:05PM >Cc: "Geert Uytterhoeven" <geert@linux-m68k.org>, "Doug Ledford" ><dledford@redhat.com>, linux-rdma@vger.kernel.org, >linux-kernel@vger.kernel.org >Subject: [EXTERNAL] Re: Re: Re: Re: [PATCH] RDMA/siw: Fix compiler >warnings on 32-bit due to u64/pointer abuse > >On Mon, Aug 19, 2019 at 03:54:56PM +0000, Bernard Metzler wrote: > >> Absolutely. But these addresses are conveyed through the >> API as unsigned 64 during post_send(), and land in the siw >> send queue as is. During send queue processing, these addresses >> must be interpreted according to its context and transformed >> (casted) back to the callers intention. I frankly do not >> know what we can do differently... The representation of >> all addresses as unsigned 64 is given. Sorry for the confusion. > >send work does not have pointers in it, so I'm confused what this is >about. Does siw allow userspace to stick an ordinary pointer for the >SG list?
Right a user references a buffer by address and local key it got during reservation of that buffer. The user can provide any VA between start of that buffer and registered length.
> >The code paths here must be totally different, so there should be >different types and functions for each case.
Yes, there is a function to process application memory (siw_rx_umem), to process a kernel PBL (siw_rx_pbl), and one to process kernel addresses (siw_rx_kva). Before running that function, the API representation of the current SGE gets translated into target buffer representation.
Thanks and best regards, Bernard.
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