From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds a special case for RAMDISK_DR using the TFO->task_sg_chaining
presented in commit a552ae31039ca8, which is required as RAMDISK_DR is used in
READ-ONLY mode for our virtual LUN0. This is done in order to setup
struct se_task->task_sg[] for the RAMDISK_DR struct se_task I/O descriptor,
and map internal ramdisk memory into SGLs used by transport_do_task_sg_chain().
Also note this patch currently prevents SCF_SCSI_DATA_SG_IO_CDB WRITE to
RAMDISK_DR backstores to prevent potentially multiple pci_map_sg() WRITE
calls to the same internally mapped RAMDISK_DR struct scatterlist memory.
This limitiation only effects RAMDISK_DR, and does not effect RAMDISK_MCP.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_rd.c | 45 +++++++++++++++++++++++++++++++++++---
1 files changed, 41 insertions(+), 4 deletions(-)
diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index c66fb77..dbf3b4c 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -40,6 +40,7 @@
#include <target/target_core_base.h>
#include <target/target_core_device.h>
#include <target/target_core_transport.h>
+#include <target/target_core_fabric_ops.h>
#include "target_core_rd.h"
@@ -1007,9 +1008,11 @@ static int rd_DIRECT_do_se_mem_map(
struct se_mem *in_se_mem,
struct se_mem **out_se_mem,
u32 *se_mem_cnt,
- u32 *task_offset)
+ u32 *task_offset_in)
{
+ struct se_cmd *cmd = task->task_se_cmd;
struct rd_request *req = (struct rd_request *) task->transport_req;
+ u32 task_offset = *task_offset_in;
int ret;
req->rd_lba = task->task_lba;
@@ -1023,12 +1026,46 @@ static int rd_DIRECT_do_se_mem_map(
if (req->rd_offset)
ret = rd_DIRECT_with_offset(task, se_mem_list, se_mem_cnt,
- task_offset);
+ task_offset_in);
else
ret = rd_DIRECT_without_offset(task, se_mem_list, se_mem_cnt,
- task_offset);
+ task_offset_in);
+
+ if (ret < 0)
+ return ret;
- return ret;
+ if (CMD_TFO(cmd)->task_sg_chaining == 0)
+ return 0;
+ /*
+ * Currently prevent writers from multiple HW fabrics doing
+ * pci_map_sg() to RD_DR's internal scatterlist memory.
+ */
+ if (cmd->data_direction == SE_DIRECTION_WRITE) {
+ printk(KERN_ERR "SE_DIRECTION_WRITE not supported for"
+ " RAMDISK_DR with task_sg_chaining=1\n");
+ return -1;
+ }
+ /*
+ * Special case for if task_sg_chaining is enabled, then
+ * we setup struct se_task->task_sg[], as it will be used by
+ * transport_do_task_sg_chain() for creating chainged SGLs
+ * across multiple struct se_task->task_sg[].
+ *
+ * Note that kfree(task->task_sg); does not need to be called
+ * in rd_DIRECT_free_DMA(), because transport_free_dev_tasks()
+ * will already be taking care of this for all TCM subsystem
+ * plugins.
+ */
+ if (!(transport_calc_sg_num(task,
+ list_entry(T_TASK(cmd)->t_mem_list->next,
+ struct se_mem, se_list),
+ task_offset)))
+ return -1;
+
+ return transport_map_mem_to_sg(task, se_mem_list, task->task_sg,
+ list_entry(T_TASK(cmd)->t_mem_list->next,
+ struct se_mem, se_list),
+ out_se_mem, se_mem_cnt, task_offset_in);
}
/* rd_DIRECT_free_DMA():
--
1.5.6.5
--
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