diff options
Diffstat (limited to 'drivers/s390')
| -rw-r--r-- | drivers/s390/scsi/zfcp_fsf.c | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index c4eb62b32a3..bec912547fb 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -1010,6 +1010,23 @@ skip_fsfstatus: send_ct->handler(send_ct->handler_data); } +static void zfcp_fsf_setup_ct_els_unchained(struct qdio_buffer_element *sbale, + struct scatterlist *sg_req, + struct scatterlist *sg_resp) +{ + sbale[0].flags |= SBAL_FLAGS0_TYPE_WRITE_READ; + sbale[2].addr = sg_virt(sg_req); + sbale[2].length = sg_req->length; + sbale[3].addr = sg_virt(sg_resp); + sbale[3].length = sg_resp->length; + sbale[3].flags |= SBAL_FLAGS_LAST_ENTRY; +} + +static int zfcp_fsf_one_sbal(struct scatterlist *sg) +{ + return sg_is_last(sg) && sg->length <= PAGE_SIZE; +} + static int zfcp_fsf_setup_ct_els_sbals(struct zfcp_fsf_req *req, struct scatterlist *sg_req, struct scatterlist *sg_resp, @@ -1020,16 +1037,16 @@ static int zfcp_fsf_setup_ct_els_sbals(struct zfcp_fsf_req *req, int bytes; if (!(feat & FSF_FEATURE_ELS_CT_CHAINED_SBALS)) { - if (sg_req->length > PAGE_SIZE || sg_resp->length > PAGE_SIZE || - !sg_is_last(sg_req) || !sg_is_last(sg_resp)) + if (!zfcp_fsf_one_sbal(sg_req) || !zfcp_fsf_one_sbal(sg_resp)) return -EOPNOTSUPP; - sbale[0].flags |= SBAL_FLAGS0_TYPE_WRITE_READ; - sbale[2].addr = sg_virt(sg_req); - sbale[2].length = sg_req->length; - sbale[3].addr = sg_virt(sg_resp); - sbale[3].length = sg_resp->length; - sbale[3].flags |= SBAL_FLAGS_LAST_ENTRY; + zfcp_fsf_setup_ct_els_unchained(sbale, sg_req, sg_resp); + return 0; + } + + /* use single, unchained SBAL if it can hold the request */ + if (zfcp_fsf_one_sbal(sg_req) && zfcp_fsf_one_sbal(sg_resp)) { + zfcp_fsf_setup_ct_els_unchained(sbale, sg_req, sg_resp); return 0; } |