On 2020-03-28 01:29, Christoph Hellwig wrote: > On Fri, Mar 27, 2020 at 08:58:09PM -0700, Bart Van Assche wrote: >> On 2020-03-20 05:16, Jack Wang wrote: >>> To avoid duplicate code in rnbd-srv, we need to reexport >>> bio_map_kern. > > NAK. If you need this helper you are doing something wrong. What is > the use case where a simple bio_add_page loop won't work? Hi Christoph, There are more users in the Linux kernel of bio_add_pc_page() than only bio_map_kern(), e.g. the SCSI target pass-through code (drivers/target/target_core_pscsi.c). The code that uses bio_map_kern() is in patch 22/26: "block/rnbd: server: functionality for IO submission to file or block dev". Isn't that use case similar to the SCSI pass-through code? I think the RNBD server code also implements storage target functionality. Thanks, Bart.
