On Tue, 2019-01-22 at 15:47 -0500, Douglas Gilbert wrote: +AD4 On 2019-01-22 1:25 p.m., Bart Van Assche wrote: +AD4 +AD4 The default behavior of the SCSI core is to set the block layer request +AD4 +AD4 queue parameter max+AF8-segment+AF8-size to 64 KB. That means that elements of +AD4 +AD4 scatterlists are limited to 64 KB. Since RDMA adapters support larger +AD4 +AD4 sizes, increase max+AF8-segment+AF8-size for the SRP initiator. +AD4 +AD4 +AD4 +AD4 Notes: +AD4 +AD4 - The SCSI max+AF8-segment+AF8-size parameter was introduced in kernel v5.0. See +AD4 +AD4 also commit 50c2e9107f17 (+ACI-scsi: introduce a max+AF8-segment+AF8-size +AD4 +AD4 host+AF8-template parameters+ACI). +AD4 +AD4 - Some other block drivers already set max+AF8-segment+AF8-size to UINT+AF8-MAX, +AD4 +AD4 e.g. nbd and rbd. +AD4 +AD4 In my sg v4 driver rewrite one of options within the SG+AF8-SET+AF8-GET+AF8-EXTENDED +AD4 ioctl is to allow the user to modify this value. It is a +ACM-define to +AD4 32 KB in the production sg v3 driver. Hi Doug, This functionality seems useful to me. But it is not clear to me how it will be guaranteed that the value set by the user won't exceed the largest max+AF8-segment+AF8-size value supported by the driver? Thanks, Bart.
