scsi: smartpqi: change aio sg processing

Take advantage of controller improvements.

Reviewed-by: Scott Teel <scott.teel@microsemi.com>
Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index 906f1aa..418f636 100644 (file)
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -4263,48 +4263,58 @@ static int pqi_build_aio_sg_list(struct pqi_ctrl_info *ctrl_info,
        int i;
        u16 iu_length;
        int sg_count;
-       unsigned int num_sg_in_iu = 0;
+       bool chained;
+       unsigned int num_sg_in_iu;
+       unsigned int max_sg_per_iu;
        struct scatterlist *sg;
        struct pqi_sg_descriptor *sg_descriptor;
 
        sg_count = scsi_dma_map(scmd);
        if (sg_count < 0)
                return sg_count;
+
+       iu_length = offsetof(struct pqi_aio_path_request, sg_descriptors) -
+               PQI_REQUEST_HEADER_LENGTH;
+       num_sg_in_iu = 0;
+
        if (sg_count == 0)
                goto out;
 
-       if (sg_count <= ctrl_info->max_sg_per_iu) {
-               sg_descriptor = &request->sg_descriptors[0];
-               scsi_for_each_sg(scmd, sg, sg_count, i) {
-                       pqi_set_sg_descriptor(sg_descriptor, sg);
-                       sg_descriptor++;
-               }
-               put_unaligned_le32(CISS_SG_LAST,
-                       &request->sg_descriptors[sg_count - 1].flags);
-               num_sg_in_iu = sg_count;
-       } else {
-               sg_descriptor = &request->sg_descriptors[0];
-               put_unaligned_le64((u64)io_request->sg_chain_buffer_dma_handle,
-                       &sg_descriptor->address);
-               put_unaligned_le32(sg_count * sizeof(*sg_descriptor),
-                       &sg_descriptor->length);
-               put_unaligned_le32(CISS_SG_CHAIN, &sg_descriptor->flags);
-
-               sg_descriptor = io_request->sg_chain_buffer;
-               scsi_for_each_sg(scmd, sg, sg_count, i) {
-                       pqi_set_sg_descriptor(sg_descriptor, sg);
-                       sg_descriptor++;
+       sg = scsi_sglist(scmd);
+       sg_descriptor = request->sg_descriptors;
+       max_sg_per_iu = ctrl_info->max_sg_per_iu - 1;
+       chained = false;
+       i = 0;
+
+       while (1) {
+               pqi_set_sg_descriptor(sg_descriptor, sg);
+               if (!chained)
+                       num_sg_in_iu++;
+               i++;
+               if (i == sg_count)
+                       break;
+               sg_descriptor++;
+               if (i == max_sg_per_iu) {
+                       put_unaligned_le64(
+                               (u64)io_request->sg_chain_buffer_dma_handle,
+                               &sg_descriptor->address);
+                       put_unaligned_le32((sg_count - num_sg_in_iu)
+                               * sizeof(*sg_descriptor),
+                               &sg_descriptor->length);
+                       put_unaligned_le32(CISS_SG_CHAIN,
+                               &sg_descriptor->flags);
+                       chained = true;
+                       num_sg_in_iu++;
+                       sg_descriptor = io_request->sg_chain_buffer;
                }
-               put_unaligned_le32(CISS_SG_LAST,
-                       &io_request->sg_chain_buffer[sg_count - 1].flags);
-               num_sg_in_iu = 1;
-               request->partial = 1;
+               sg = sg_next(sg);
        }
 
-out:
-       iu_length = offsetof(struct pqi_aio_path_request, sg_descriptors) -
-               PQI_REQUEST_HEADER_LENGTH;
+       put_unaligned_le32(CISS_SG_LAST, &sg_descriptor->flags);
+       request->partial = chained;
        iu_length += num_sg_in_iu * sizeof(*sg_descriptor);
+
+out:
        put_unaligned_le16(iu_length, &request->header.iu_length);
        request->num_sg_descriptors = num_sg_in_iu;