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iser-target: Change the recv buffers posting logic
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iser target batches post recv operations to avoid
the overhead of acquiring the recv queue lock and
posting a HW doorbell for each command.

We change it to be per command in order to support
zcopy immediate data for IOs that fits in the 8K
transfer boundary (in the next patch).

(Fix minor patch fuzz due to ib_mr removal - nab)

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Jenny Derzhavetz authored and Nicholas Bellinger committed Sep 15, 2015
1 parent bd37922 commit 4366b19
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Showing 2 changed files with 67 additions and 48 deletions.
111 changes: 65 additions & 46 deletions drivers/infiniband/ulp/isert/ib_isert.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -238,8 +238,6 @@ isert_alloc_rx_descriptors(struct isert_conn *isert_conn)
rx_sg->lkey = device->pd->local_dma_lkey;
}

isert_conn->rx_desc_head = 0;

return 0;

dma_map_fail:
Expand Down Expand Up @@ -1002,35 +1000,51 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
}

static int
isert_post_recv(struct isert_conn *isert_conn, u32 count)
isert_post_recvm(struct isert_conn *isert_conn, u32 count)
{
struct ib_recv_wr *rx_wr, *rx_wr_failed;
int i, ret;
unsigned int rx_head = isert_conn->rx_desc_head;
struct iser_rx_desc *rx_desc;

for (rx_wr = isert_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
rx_desc = &isert_conn->rx_descs[rx_head];
rx_wr->wr_id = (uintptr_t)rx_desc;
rx_wr->sg_list = &rx_desc->rx_sg;
rx_wr->num_sge = 1;
rx_wr->next = rx_wr + 1;
rx_head = (rx_head + 1) & (ISERT_QP_MAX_RECV_DTOS - 1);
rx_desc = &isert_conn->rx_descs[i];
rx_wr->wr_id = (uintptr_t)rx_desc;
rx_wr->sg_list = &rx_desc->rx_sg;
rx_wr->num_sge = 1;
rx_wr->next = rx_wr + 1;
}

rx_wr--;
rx_wr->next = NULL; /* mark end of work requests list */

isert_conn->post_recv_buf_count += count;
ret = ib_post_recv(isert_conn->qp, isert_conn->rx_wr,
&rx_wr_failed);
&rx_wr_failed);
if (ret) {
isert_err("ib_post_recv() failed with ret: %d\n", ret);
isert_conn->post_recv_buf_count -= count;
} else {
isert_dbg("Posted %d RX buffers\n", count);
isert_conn->rx_desc_head = rx_head;
}

return ret;
}

static int
isert_post_recv(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc)
{
struct ib_recv_wr *rx_wr_failed, rx_wr;
int ret;

rx_wr.wr_id = (uintptr_t)rx_desc;
rx_wr.sg_list = &rx_desc->rx_sg;
rx_wr.num_sge = 1;
rx_wr.next = NULL;

isert_conn->post_recv_buf_count++;
ret = ib_post_recv(isert_conn->qp, &rx_wr, &rx_wr_failed);
if (ret) {
isert_err("ib_post_recv() failed with ret: %d\n", ret);
isert_conn->post_recv_buf_count--;
}

return ret;
}

Expand Down Expand Up @@ -1201,7 +1215,8 @@ isert_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login,
if (ret)
return ret;

ret = isert_post_recv(isert_conn, ISERT_MIN_POSTED_RX);
ret = isert_post_recvm(isert_conn,
ISERT_QP_MAX_RECV_DTOS);
if (ret)
return ret;

Expand Down Expand Up @@ -1274,7 +1289,7 @@ isert_rx_login_req(struct isert_conn *isert_conn)
}

static struct iscsi_cmd
*isert_allocate_cmd(struct iscsi_conn *conn)
*isert_allocate_cmd(struct iscsi_conn *conn, struct iser_rx_desc *rx_desc)
{
struct isert_conn *isert_conn = conn->context;
struct isert_cmd *isert_cmd;
Expand All @@ -1288,6 +1303,7 @@ static struct iscsi_cmd
isert_cmd = iscsit_priv_cmd(cmd);
isert_cmd->conn = isert_conn;
isert_cmd->iscsi_cmd = cmd;
isert_cmd->rx_desc = rx_desc;

return cmd;
}
Expand Down Expand Up @@ -1403,6 +1419,15 @@ isert_handle_iscsi_dataout(struct isert_conn *isert_conn,
if (rc < 0)
return rc;

/*
* multiple data-outs on the same command can arrive -
* so post the buffer before hand
*/
rc = isert_post_recv(isert_conn, rx_desc);
if (rc) {
isert_err("ib_post_recv failed with %d\n", rc);
return rc;
}
return 0;
}

Expand Down Expand Up @@ -1475,7 +1500,7 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,

switch (opcode) {
case ISCSI_OP_SCSI_CMD:
cmd = isert_allocate_cmd(conn);
cmd = isert_allocate_cmd(conn, rx_desc);
if (!cmd)
break;

Expand All @@ -1489,7 +1514,7 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
rx_desc, (unsigned char *)hdr);
break;
case ISCSI_OP_NOOP_OUT:
cmd = isert_allocate_cmd(conn);
cmd = isert_allocate_cmd(conn, rx_desc);
if (!cmd)
break;

Expand All @@ -1502,30 +1527,28 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
(unsigned char *)hdr);
break;
case ISCSI_OP_SCSI_TMFUNC:
cmd = isert_allocate_cmd(conn);
cmd = isert_allocate_cmd(conn, rx_desc);
if (!cmd)
break;

ret = iscsit_handle_task_mgt_cmd(conn, cmd,
(unsigned char *)hdr);
break;
case ISCSI_OP_LOGOUT:
cmd = isert_allocate_cmd(conn);
cmd = isert_allocate_cmd(conn, rx_desc);
if (!cmd)
break;

ret = iscsit_handle_logout_cmd(conn, cmd, (unsigned char *)hdr);
break;
case ISCSI_OP_TEXT:
if (be32_to_cpu(hdr->ttt) != 0xFFFFFFFF) {
if (be32_to_cpu(hdr->ttt) != 0xFFFFFFFF)
cmd = iscsit_find_cmd_from_itt(conn, hdr->itt);
if (!cmd)
break;
} else {
cmd = isert_allocate_cmd(conn);
if (!cmd)
break;
}
else
cmd = isert_allocate_cmd(conn, rx_desc);

if (!cmd)
break;

isert_cmd = iscsit_priv_cmd(cmd);
ret = isert_handle_text_cmd(isert_conn, isert_cmd, cmd,
Expand Down Expand Up @@ -1585,7 +1608,7 @@ isert_rcv_completion(struct iser_rx_desc *desc,
struct ib_device *ib_dev = isert_conn->cm_id->device;
struct iscsi_hdr *hdr;
u64 rx_dma;
int rx_buflen, outstanding;
int rx_buflen;

if ((char *)desc == isert_conn->login_req_buf) {
rx_dma = isert_conn->login_req_dma;
Expand Down Expand Up @@ -1625,22 +1648,6 @@ isert_rcv_completion(struct iser_rx_desc *desc,
DMA_FROM_DEVICE);

isert_conn->post_recv_buf_count--;
isert_dbg("Decremented post_recv_buf_count: %d\n",
isert_conn->post_recv_buf_count);

if ((char *)desc == isert_conn->login_req_buf)
return;

outstanding = isert_conn->post_recv_buf_count;
if (outstanding + ISERT_MIN_POSTED_RX <= ISERT_QP_MAX_RECV_DTOS) {
int err, count = min(ISERT_QP_MAX_RECV_DTOS - outstanding,
ISERT_MIN_POSTED_RX);
err = isert_post_recv(isert_conn, count);
if (err) {
isert_err("isert_post_recv() count: %d failed, %d\n",
count, err);
}
}
}

static int
Expand Down Expand Up @@ -2152,6 +2159,12 @@ isert_post_response(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd)
struct ib_send_wr *wr_failed;
int ret;

ret = isert_post_recv(isert_conn, isert_cmd->rx_desc);
if (ret) {
isert_err("ib_post_recv failed with %d\n", ret);
return ret;
}

ret = ib_post_send(isert_conn->qp, &isert_cmd->tx_desc.send_wr,
&wr_failed);
if (ret) {
Expand Down Expand Up @@ -2946,6 +2959,12 @@ isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
&isert_cmd->tx_desc.send_wr);
isert_cmd->rdma_wr.s_send_wr.next = &isert_cmd->tx_desc.send_wr;
wr->send_wr_num += 1;

rc = isert_post_recv(isert_conn, isert_cmd->rx_desc);
if (rc) {
isert_err("ib_post_recv failed with %d\n", rc);
return rc;
}
}

rc = ib_post_send(isert_conn->qp, wr->send_wr, &wr_failed);
Expand Down
4 changes: 2 additions & 2 deletions drivers/infiniband/ulp/isert/ib_isert.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,7 @@ struct isert_cmd {
struct isert_conn *conn;
struct iscsi_cmd *iscsi_cmd;
struct iser_tx_desc tx_desc;
struct iser_rx_desc *rx_desc;
struct isert_rdma_wr rdma_wr;
struct work_struct comp_work;
};
Expand All @@ -155,9 +156,8 @@ struct isert_conn {
u64 login_req_dma;
int login_req_len;
u64 login_rsp_dma;
unsigned int rx_desc_head;
struct iser_rx_desc *rx_descs;
struct ib_recv_wr rx_wr[ISERT_MIN_POSTED_RX];
struct ib_recv_wr rx_wr[ISERT_QP_MAX_RECV_DTOS];
struct iscsi_conn *conn;
struct list_head node;
struct completion login_comp;
Expand Down

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