On Sat, Mar 28, 2020 at 09:16:55AM -0700, Bart Van Assche wrote: > 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. No, it is not at all. The RNBD case submits normal read/write bios, for which bio_map_kerl is the wrong interfac given that it uses bio_add_pc_page. Read, write and other non-passthrough requests must use bio_add_page instead.
