From: Kiran Patil <[email protected]>
Fix: Added support in TCM/LIO target to offload large FC receives.
Technical Details:
1. Modified TCM/LIO files (tfc*) to add support for receive offload.
2. Setup target to support task_sg_chaining by setting bit during
registration with TCM fabric.
3. Fix the panic (NULL pointer access) in function transport_calc_sg_num.
Signed-off-by: Kiran Patil <[email protected]>
---
drivers/target/target_core_transport.c | 8 ++++
drivers/target/tcm_fc/tcm_fc.h | 3 ++
drivers/target/tcm_fc/tfc_cmd.c | 33 ++++++++++++++++-
drivers/target/tcm_fc/tfc_conf.c | 4 ++
drivers/target/tcm_fc/tfc_io.c | 64 ++++++++++++++++++++++++++++++++
5 files changed, 109 insertions(+), 3 deletions(-)
diff --git a/drivers/target/target_core_transport.c
b/drivers/target/target_core_transport.c
index 0a35a5c..9ad38c5 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -7324,7 +7324,13 @@ next:
*/
if (task->task_padded_sg) {
sg_mark_end(&task->task_sg[task->task_sg_num - 1]);
- sg_mark_end(&task->task_sg_bidi[task->task_sg_num - 1]);
+ /*
+ * Added the 'if' check before marking end of bi-directional
+ * scatterlist (which gets created only in case of request
+ * (RD + WR).
+ */
+ if (task->task_sg_bidi)
+ sg_mark_end(&task->task_sg_bidi[task->task_sg_num - 1]);
}
DEBUG_SC("Successfully allocated task->task_sg_num(%u),"
diff --git a/drivers/target/tcm_fc/tcm_fc.h b/drivers/target/tcm_fc/tcm_fc.h
index 210c33e..8468736 100644
--- a/drivers/target/tcm_fc/tcm_fc.h
+++ b/drivers/target/tcm_fc/tcm_fc.h
@@ -153,6 +153,9 @@ struct ft_cmd {
u32 write_data_len; /* data received on writes */
struct se_queue_req se_req;
unsigned char ft_sense_buffer[TRANSPORT_SENSE_BUFFER]; /* Local sense
buffer */
+ u32 was_ddp_setup:1; /* Set only if ddp is setup */
+ struct scatterlist *sg; /* Set only if DDP is setup */
+ u32 sg_cnt; /* No. of item in scatterlist */
};
extern struct list_head ft_lport_list;
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index e5b6aa1..aaf9b26 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -72,9 +72,9 @@ void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
printk(KERN_INFO "%s: cmd %p lun %d\n", caller, cmd, cmd->lun);
task = T_TASK(se_cmd);
- printk(KERN_INFO "%s: cmd %p task %p se_num %u buf %p len %u\n",
+ printk(KERN_INFO "%s: cmd %p task %p se_num %u buf %p len %u
se_cmd_flags <0x%x>\n",
caller, cmd, task, task->t_tasks_se_num,
- task->t_task_buf, se_cmd->data_length);
+ task->t_task_buf, se_cmd->data_length, se_cmd->se_cmd_flags);
if (task->t_mem_list)
list_for_each_entry(mem, task->t_mem_list, se_list)
printk(KERN_INFO "%s: cmd %p mem %p page %p "
@@ -247,6 +247,8 @@ int ft_write_pending(struct se_cmd *se_cmd)
struct fcp_txrdy *txrdy;
struct fc_lport *lport;
struct fc_exch *ep;
+ struct fc_frame_header *fh;
+ u32 f_ctl;
ft_dump_cmd(cmd, __func__);
@@ -264,6 +266,33 @@ int ft_write_pending(struct se_cmd *se_cmd)
fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
FC_FC_EX_CTX | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
+ fh = fc_frame_header_get(fp);
+ f_ctl = ntoh24(fh->fh_f_ctl);
+
+ /* Only if it is 'Exchange Responder' */
+ if (f_ctl & FC_FC_EX_CTX) {
+ /* Target is 'exchange responder' and sending XFER_READY
+ * to 'exchange initiator (initiator)'
+ */
+ if (ep->xid <= lport->lro_xid &&
+ fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC) {
+ if (se_cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB) {
+ /*
+ * Map se_mem list to scatterlist, so that
+ * DDP can be setup. DDP setup function require
+ * scatterlist. se_mem_list is internal to
+ * TCM/LIO target
+ */
+ transport_do_task_sg_chain(se_cmd);
+ cmd->sg = T_TASK(se_cmd)->t_tasks_sg_chained;
+ cmd->sg_cnt =
+ T_TASK(se_cmd)->t_tasks_sg_chained_no;
+ }
+ if (cmd->sg && lport->tt.ddp_setup(lport, ep->xid,
+ cmd->sg, cmd->sg_cnt))
+ cmd->was_ddp_setup = 1;
+ }
+ }
lport->tt.seq_send(lport, cmd->seq, fp);
return 0;
}
diff --git a/drivers/target/tcm_fc/tfc_conf.c b/drivers/target/tcm_fc/tfc_conf.c
index 604c97d..3668c04 100644
--- a/drivers/target/tcm_fc/tfc_conf.c
+++ b/drivers/target/tcm_fc/tfc_conf.c
@@ -598,6 +598,10 @@ int ft_register_configfs(void)
return -1;
}
fabric->tf_ops = ft_fabric_ops;
+
+ /* Allowing support for task_sg_chaining */
+ fabric->tf_ops.task_sg_chaining = 1;
+
/*
* Setup default attribute lists for various fabric->tf_cit_tmpl
*/
diff --git a/drivers/target/tcm_fc/tfc_io.c b/drivers/target/tcm_fc/tfc_io.c
index 2080891..e77a45a 100644
--- a/drivers/target/tcm_fc/tfc_io.c
+++ b/drivers/target/tcm_fc/tfc_io.c
@@ -188,6 +188,9 @@ int ft_queue_data_in(struct se_cmd *se_cmd)
void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
{
struct se_cmd *se_cmd = &cmd->se_cmd;
+ struct fc_seq *seq = cmd->seq;
+ struct fc_exch *ep;
+ struct fc_lport *lport;
struct se_transport_task *task;
struct fc_frame_header *fh;
struct se_mem *mem;
@@ -200,6 +203,8 @@ void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame
*fp)
void *page_addr;
void *from;
void *to;
+ u32 f_ctl;
+ void *buf;
task = T_TASK(se_cmd);
BUG_ON(!task);
@@ -207,6 +212,64 @@ void ft_recv_write_data(struct ft_cmd *cmd, struct
fc_frame *fp)
fh = fc_frame_header_get(fp);
if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
goto drop;
+
+ /*
+ * Doesn't expect even single byte of payload. Payload
+ * is expected to be copied directly to user buffers
+ * due to DDP (Large Rx offload) feature, hence
+ * BUG_ON if BUF is non-NULL
+ */
+ buf = fc_frame_payload_get(fp, 1);
+ if (cmd->was_ddp_setup && buf) {
+ printk(KERN_INFO "%s: When DDP was setup, not expected to"
+ "receive frame with payload, Payload shall be"
+ "copied directly to buffer instead of coming "
+ "via. legacy receive queues\n", __func__);
+ BUG_ON(buf);
+ }
+
+ /*
+ * If ft_cmd indicated 'ddp_setup', in that case only the last frame
+ * should come with 'TSI bit being set'. If 'TSI bit is not set and if
+ * data frame appears here, means error condition. In both the cases
+ * release the DDP context (ddp_put) and in error case, as well
+ * initiate error recovery mechanism.
+ */
+ ep = fc_seq_exch(seq);
+ if (cmd->was_ddp_setup) {
+ BUG_ON(!ep);
+ lport = ep->lp;
+ BUG_ON(!lport);
+ }
+ if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
+ f_ctl = ntoh24(fh->fh_f_ctl);
+ /*
+ * If TSI bit set in f_ctl, means last write data frame is
+ * received successfully where payload is posted directly
+ * to user buffer and only the last frame's header is posted
+ * in legacy receive queue
+ */
+ if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
+ cmd->write_data_len = lport->tt.ddp_done(lport,
+ ep->xid);
+ goto last_frame;
+ } else {
+ /*
+ * Updating the write_data_len may be meaningless at
+ * this point, but just in case if required in future
+ * for debugging or any other purpose
+ */
+ printk(KERN_ERR "%s: Received frame with TSI bit not"
+ " being SET, dropping the frame, "
+ "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
+ __func__, cmd->sg, cmd->sg_cnt);
+ cmd->write_data_len = lport->tt.ddp_done(lport,
+ ep->xid);
+ lport->tt.seq_exch_abort(cmd->seq, 0);
+ goto drop;
+ }
+ }
+
rel_off = ntohl(fh->fh_parm_offset);
frame_len = fr_len(fp);
if (frame_len <= sizeof(*fh))
@@ -273,6 +336,7 @@ void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame
*fp)
mem_len -= tlen;
cmd->write_data_len += tlen;
}
+last_frame:
if (cmd->write_data_len == se_cmd->data_length)
transport_generic_handle_data(se_cmd);
drop:
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