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>

1 files changed, 39 insertions, 29 deletions

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index 906f1aaf7cd2..418f63670d71 100644
--- 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;