target: Make all control CDBs scatter-gather

Previously, some control CDBs did not allocate memory in pages for their
data buffer, but just did a kmalloc. This patch makes all cdbs allocate
pages.

This has the benefit of streamlining some paths that had to behave
differently when we used two allocation methods. The downside is that
all accesses to the data buffer need to kmap it before use, and need to
handle data in page-sized chunks if more than a page is needed for a given
command's data buffer.

Finally, note that cdbs with no data buffers are handled a little
differently. Before, SCSI_NON_DATA_CDBs would not call get_mem at all
(they'd be in the final else in transport_allocate_resources) but now
these will make it into generic_get_mem, but just not allocate any
buffers.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 3 insertions, 29 deletions

diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 3574c520a5f4..d9569242e3dc 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -695,7 +695,7 @@ static int pscsi_transport_complete(struct se_task *task)
 
                 if (task->task_se_cmd->se_deve->lun_flags &
                                 TRANSPORT_LUNFLAGS_READ_ONLY) {
-                        unsigned char *buf = task->task_se_cmd->t_task_buf;
+                        unsigned char *buf = transport_kmap_first_data_page(task->task_se_cmd);
 
                         if (cdb[0] == MODE_SENSE_10) {
                                 if (!(buf[3] & 0x80))
@@ -704,6 +704,8 @@ static int pscsi_transport_complete(struct se_task *task)
                                 if (!(buf[2] & 0x80))
                                         buf[2] |= 0x80;
                         }
+
+                        transport_kunmap_first_data_page(task->task_se_cmd);
                 }
         }
 after_mode_sense:
@@ -1246,33 +1248,6 @@ static int pscsi_map_task_SG(struct se_task *task)
         return 0;
 }
 
-/*      pscsi_map_task_non_SG():
- *
- *
- */
-static int pscsi_map_task_non_SG(struct se_task *task)
-{
-        struct se_cmd *cmd = task->task_se_cmd;
-        struct pscsi_plugin_task *pt = PSCSI_TASK(task);
-        struct pscsi_dev_virt *pdv = task->se_dev->dev_ptr;
-        int ret = 0;
-
-        if (pscsi_blk_get_request(task) < 0)
-                return PYX_TRANSPORT_LU_COMM_FAILURE;
-
-        if (!task->task_size)
-                return 0;
-
-        ret = blk_rq_map_kern(pdv->pdv_sd->request_queue,
-                        pt->pscsi_req, cmd->t_task_buf,
-                        task->task_size, GFP_KERNEL);
-        if (ret < 0) {
-                printk(KERN_ERR "PSCSI: blk_rq_map_kern() failed: %d\n", ret);
-                return PYX_TRANSPORT_LU_COMM_FAILURE;
-        }
-        return 0;
-}
-
 static int pscsi_CDB_none(struct se_task *task)
 {
         return pscsi_blk_get_request(task);
@@ -1392,7 +1367,6 @@ static struct se_subsystem_api pscsi_template = {
         .owner                  = THIS_MODULE,
         .transport_type         = TRANSPORT_PLUGIN_PHBA_PDEV,
         .cdb_none               = pscsi_CDB_none,
-        .map_task_non_SG        = pscsi_map_task_non_SG,
         .map_task_SG            = pscsi_map_task_SG,
         .attach_hba             = pscsi_attach_hba,
         .detach_hba             = pscsi_detach_hba,