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RDMA/srp: Add support for immediate data

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Request permission to send immediate data during login. If the SRP
target grants this request, send the payload of write requests <= 8 KB
as immediate data.

Cc: Sergey Gorenko <sergeygo@mellanox.com>
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Bart Van Assche 2018-12-17 13:20:39 -08:00 committed by Doug Ledford
parent 513d564711
commit 882981f4a4
2 changed files with 89 additions and 14 deletions
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91
drivers/infiniband/ulp/srp/ib_srp.c
View File

@ -132,6 +132,15 @@ MODULE_PARM_DESC(dev_loss_tmo,
" if fast_io_fail_tmo has not been set. \"off\" means that"
" this functionality is disabled.");
static bool srp_use_imm_data = true;
module_param_named(use_imm_data, srp_use_imm_data, bool, 0644);
MODULE_PARM_DESC(use_imm_data,
"Whether or not to request permission to use immediate data during SRP login.");
static unsigned int srp_max_imm_data = 8 * 1024;
module_param_named(max_imm_data, srp_max_imm_data, uint, 0644);
MODULE_PARM_DESC(max_imm_data, "Maximum immediate data size.");
static unsigned ch_count;
module_param(ch_count, uint, 0444);
MODULE_PARM_DESC(ch_count,
@ -573,7 +582,7 @@ static int srp_create_ch_ib(struct srp_rdma_ch *ch)
init_attr->cap.max_send_wr = m * target->queue_size;
init_attr->cap.max_recv_wr = target->queue_size + 1;
init_attr->cap.max_recv_sge = 1;
init_attr->cap.max_send_sge = 1;
init_attr->cap.max_send_sge = SRP_MAX_SGE;
init_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
init_attr->qp_type = IB_QPT_RC;
init_attr->send_cq = send_cq;
@ -858,6 +867,10 @@ static int srp_send_req(struct srp_rdma_ch *ch, uint32_t max_iu_len,
SRP_BUF_FORMAT_INDIRECT);
req->ib_req.req_flags = (multich ? SRP_MULTICHAN_MULTI :
SRP_MULTICHAN_SINGLE);
if (srp_use_imm_data) {
req->ib_req.req_flags |= SRP_IMMED_REQUESTED;
req->ib_req.imm_data_offset = cpu_to_be16(SRP_IMM_DATA_OFFSET);
}
if (target->using_rdma_cm) {
req->rdma_param.flow_control = req->ib_param.flow_control;
@ -874,6 +887,7 @@ static int srp_send_req(struct srp_rdma_ch *ch, uint32_t max_iu_len,
req->rdma_req.req_it_iu_len = req->ib_req.req_it_iu_len;
req->rdma_req.req_buf_fmt = req->ib_req.req_buf_fmt;
req->rdma_req.req_flags = req->ib_req.req_flags;
req->rdma_req.imm_data_offset = req->ib_req.imm_data_offset;
ipi = req->rdma_req.initiator_port_id;
tpi = req->rdma_req.target_port_id;
@ -1347,12 +1361,16 @@ static void srp_terminate_io(struct srp_rport *rport)
}
/* Calculate maximum initiator to target information unit length. */
static uint32_t srp_max_it_iu_len(int cmd_sg_cnt)
static uint32_t srp_max_it_iu_len(int cmd_sg_cnt, bool use_imm_data)
{
uint32_t max_iu_len = sizeof(struct srp_cmd) + SRP_MAX_ADD_CDB_LEN +
sizeof(struct srp_indirect_buf) +
cmd_sg_cnt * sizeof(struct srp_direct_buf);
if (use_imm_data)
max_iu_len = max(max_iu_len, SRP_IMM_DATA_OFFSET +
srp_max_imm_data);
return max_iu_len;
}
@ -1369,7 +1387,8 @@ static int srp_rport_reconnect(struct srp_rport *rport)
{
struct srp_target_port *target = rport->lld_data;
struct srp_rdma_ch *ch;
uint32_t max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt);
uint32_t max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
srp_use_imm_data);
int i, j, ret = 0;
bool multich = false;
@ -1777,23 +1796,27 @@ static void srp_check_mapping(struct srp_map_state *state,
* @req: SRP request
*
* Returns the length in bytes of the SRP_CMD IU or a negative value if
* mapping failed.
* mapping failed. The size of any immediate data is not included in the
* return value.
*/
static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
struct srp_request *req)
{
struct srp_target_port *target = ch->target;
struct scatterlist *scat;
struct scatterlist *scat, *sg;
struct srp_cmd *cmd = req->cmd->buf;
int len, nents, count, ret;
int i, len, nents, count, ret;
struct srp_device *dev;
struct ib_device *ibdev;
struct srp_map_state state;
struct srp_indirect_buf *indirect_hdr;
u64 data_len;
u32 idb_len, table_len;
__be32 idb_rkey;
u8 fmt;
req->cmd->num_sge = 1;
if (!scsi_sglist(scmnd) || scmnd->sc_data_direction == DMA_NONE)
return sizeof(struct srp_cmd) + cmd->add_cdb_len;
@ -1807,6 +1830,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
nents = scsi_sg_count(scmnd);
scat = scsi_sglist(scmnd);
data_len = scsi_bufflen(scmnd);
dev = target->srp_host->srp_dev;
ibdev = dev->dev;
@ -1815,6 +1839,28 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
if (unlikely(count == 0))
return -EIO;
if (ch->use_imm_data &&
count <= SRP_MAX_IMM_SGE &&
SRP_IMM_DATA_OFFSET + data_len <= ch->max_it_iu_len &&
scmnd->sc_data_direction == DMA_TO_DEVICE) {
struct srp_imm_buf *buf;
struct ib_sge *sge = &req->cmd->sge[1];
fmt = SRP_DATA_DESC_IMM;
len = SRP_IMM_DATA_OFFSET;
req->nmdesc = 0;
buf = (void *)cmd->add_data + cmd->add_cdb_len;
buf->len = cpu_to_be32(data_len);
WARN_ON_ONCE((void *)(buf + 1) > (void *)cmd + len);
for_each_sg(scat, sg, count, i) {
sge[i].addr = ib_sg_dma_address(ibdev, sg);
sge[i].length = ib_sg_dma_len(ibdev, sg);
sge[i].lkey = target->lkey;
}
req->cmd->num_sge += count;
goto map_complete;
}
fmt = SRP_DATA_DESC_DIRECT;
len = sizeof(struct srp_cmd) + cmd->add_cdb_len +
sizeof(struct srp_direct_buf);
@ -2018,22 +2064,30 @@ static void srp_send_done(struct ib_cq *cq, struct ib_wc *wc)
list_add(&iu->list, &ch->free_tx);
}
/**
* srp_post_send() - send an SRP information unit
* @ch: RDMA channel over which to send the information unit.
* @iu: Information unit to send.
* @len: Length of the information unit excluding immediate data.
*/
static int srp_post_send(struct srp_rdma_ch *ch, struct srp_iu *iu, int len)
{
struct srp_target_port *target = ch->target;
struct ib_sge list;
struct ib_send_wr wr;
list.addr = iu->dma;
list.length = len;
list.lkey = target->lkey;
if (WARN_ON_ONCE(iu->num_sge > SRP_MAX_SGE))
return -EINVAL;
iu->sge[0].addr = iu->dma;
iu->sge[0].length = len;
iu->sge[0].lkey = target->lkey;
iu->cqe.done = srp_send_done;
wr.next = NULL;
wr.wr_cqe = &iu->cqe;
wr.sg_list = &list;
wr.num_sge = 1;
wr.sg_list = &iu->sge[0];
wr.num_sge = iu->num_sge;
wr.opcode = IB_WR_SEND;
wr.send_flags = IB_SEND_SIGNALED;
@ -2146,6 +2200,7 @@ static int srp_response_common(struct srp_rdma_ch *ch, s32 req_delta,
return 1;
}
iu->num_sge = 1;
ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
memcpy(iu->buf, rsp, len);
ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
@ -2500,10 +2555,16 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
if (lrsp->opcode == SRP_LOGIN_RSP) {
ch->max_ti_iu_len = be32_to_cpu(lrsp->max_ti_iu_len);
ch->req_lim = be32_to_cpu(lrsp->req_lim_delta);
ch->max_it_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt);
ch->use_imm_data = lrsp->rsp_flags & SRP_LOGIN_RSP_IMMED_SUPP;
ch->max_it_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
ch->use_imm_data);
WARN_ON_ONCE(ch->max_it_iu_len >
be32_to_cpu(lrsp->max_it_iu_len));
if (ch->use_imm_data)
shost_printk(KERN_DEBUG, target->scsi_host,
PFX "using immediate data\n");
/*
* Reserve credits for task management so we don't
* bounce requests back to the SCSI mid-layer.
@ -2891,6 +2952,8 @@ static int srp_send_tsk_mgmt(struct srp_rdma_ch *ch, u64 req_tag, u64 lun,
return -1;
}
iu->num_sge = 1;
ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
DMA_TO_DEVICE);
tsk_mgmt = iu->buf;
@ -3856,7 +3919,7 @@ static ssize_t srp_create_target(struct device *dev,
target->mr_per_cmd = mr_per_cmd;
target->indirect_size = target->sg_tablesize *
sizeof (struct srp_direct_buf);
max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt);
max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt, srp_use_imm_data);
INIT_WORK(&target->tl_err_work, srp_tl_err_work);
INIT_WORK(&target->remove_work, srp_remove_work);

12
drivers/infiniband/ulp/srp/ib_srp.h
View File

@ -69,6 +69,15 @@ enum {
SRP_MAX_PAGES_PER_MR = 512,
SRP_MAX_ADD_CDB_LEN = 16,
SRP_MAX_IMM_SGE = 2,
SRP_MAX_SGE = SRP_MAX_IMM_SGE + 1,
/*
* Choose the immediate data offset such that a 32 byte CDB still fits.
*/
SRP_IMM_DATA_OFFSET = sizeof(struct srp_cmd) +
SRP_MAX_ADD_CDB_LEN +
sizeof(struct srp_imm_buf),
};
enum srp_target_state {
@ -152,6 +161,7 @@ struct srp_rdma_ch {
};
uint32_t max_it_iu_len;
uint32_t max_ti_iu_len;
bool use_imm_data;
/* Everything above this point is used in the hot path of
* command processing. Try to keep them packed into cachelines.
@ -263,6 +273,8 @@ struct srp_iu {
void *buf;
size_t size;
enum dma_data_direction direction;
u32 num_sge;
struct ib_sge sge[SRP_MAX_SGE];
struct ib_cqe cqe;
};