[RFC 3/8] IB/srp: allow sg_tablesize to be set for each target

David Dillow
2011-01-19T04:27:17Z

Different configurations of target software allow differing max sizes of
the command IU. Allowing this to be changed per-target allows all
targets on an initiator to get an optimal setting.

We deprecate srp_sg_tablesize and replace it with cmd_sg_entries in
preparation for allowing more indirect descriptors than can fit in the
IU.
---
topspin_workarounds could become a bool here as well as a cleanup

drivers/infiniband/ulp/srp/ib_srp.c | 81 ++++++++++++++++++++++++----------
drivers/infiniband/ulp/srp/ib_srp.h | 2 +
2 files changed, 59 insertions(+), 24 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 060e6a8..6f8ee0c 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -59,14 +59,16 @@ MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator "
"v" DRV_VERSION " (" DRV_RELDATE ")");
MODULE_LICENSE("Dual BSD/GPL");

-static int srp_sg_tablesize = SRP_DEF_SG_TABLESIZE;
-static int srp_max_iu_len;
+static unsigned int srp_sg_tablesize;
+static unsigned int cmd_sg_entries;
+static int topspin_workarounds = 1;

-module_param(srp_sg_tablesize, int, 0444);
-MODULE_PARM_DESC(srp_sg_tablesize,
- "Max number of gather/scatter entries per I/O (default is 12, max 255)");
+module_param(srp_sg_tablesize, uint, 0444);
+MODULE_PARM_DESC(srp_sg_tablesize, "Deprecated name for cmd_sg_entries");

-static int topspin_workarounds = 1;
+module_param(cmd_sg_entries, uint, 0444);
+MODULE_PARM_DESC(cmd_sg_entries,
+ "Default number of gather/scatter entries in the SRP command (default is 12, max 255)");

module_param(topspin_workarounds, int, 0444);
MODULE_PARM_DESC(topspin_workarounds,
@@ -364,7 +366,7 @@ static int srp_send_req(struct srp_target_port *target)

req->priv.opcode = SRP_LOGIN_REQ;
req->priv.tag = 0;
- req->priv.req_it_iu_len = cpu_to_be32(srp_max_iu_len);
+ req->priv.req_it_iu_len = cpu_to_be32(target->max_iu_len);
req->priv.req_buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
SRP_BUF_FORMAT_INDIRECT);
/*
@@ -1125,7 +1127,7 @@ static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
spin_unlock_irqrestore(&target->lock, flags);

dev = target->srp_host->srp_dev->dev;
- ib_dma_sync_single_for_cpu(dev, iu->dma, srp_max_iu_len,
+ ib_dma_sync_single_for_cpu(dev, iu->dma, target->max_iu_len,
DMA_TO_DEVICE);

scmnd->result = 0;
@@ -1149,7 +1151,7 @@ static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
goto err_iu;
}

- ib_dma_sync_single_for_device(dev, iu->dma, srp_max_iu_len,
+ ib_dma_sync_single_for_device(dev, iu->dma, target->max_iu_len,
DMA_TO_DEVICE);

if (srp_post_send(target, iu, len)) {
@@ -1189,7 +1191,7 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)

for (i = 0; i < SRP_SQ_SIZE; ++i) {
target->tx_ring[i] = srp_alloc_iu(target->srp_host,
- srp_max_iu_len,
+ target->max_iu_len,
GFP_KERNEL, DMA_TO_DEVICE);
if (!target->tx_ring[i])
goto err;
@@ -1645,6 +1647,14 @@ static ssize_t show_local_ib_device(struct device *dev,
return sprintf(buf, "%s\n", target->srp_host->srp_dev->dev->name);
}

+static ssize_t show_cmd_sg_entries(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct srp_target_port *target = host_to_target(class_to_shost(dev));
+
+ return sprintf(buf, "%u\n", target->cmd_sg_cnt);
+}
+
static DEVICE_ATTR(id_ext, S_IRUGO, show_id_ext, NULL);
static DEVICE_ATTR(ioc_guid, S_IRUGO, show_ioc_guid, NULL);
static DEVICE_ATTR(service_id, S_IRUGO, show_service_id, NULL);
@@ -1655,6 +1665,7 @@ static DEVICE_ATTR(req_lim, S_IRUGO, show_req_lim, NULL);
static DEVICE_ATTR(zero_req_lim, S_IRUGO, show_zero_req_lim, NULL);
static DEVICE_ATTR(local_ib_port, S_IRUGO, show_local_ib_port, NULL);
static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);
+static DEVICE_ATTR(cmd_sg_entries, S_IRUGO, show_cmd_sg_entries, NULL);

static struct device_attribute *srp_host_attrs[] = {
&dev_attr_id_ext,
@@ -1667,6 +1678,7 @@ static struct device_attribute *srp_host_attrs[] = {
&dev_attr_zero_req_lim,
&dev_attr_local_ib_port,
&dev_attr_local_ib_device,
+ &dev_attr_cmd_sg_entries,
NULL
};

@@ -1679,6 +1691,7 @@ static struct scsi_host_template srp_template = {
.eh_abort_handler = srp_abort,
.eh_device_reset_handler = srp_reset_device,
.eh_host_reset_handler = srp_reset_host,
+ .sg_tablesize = SRP_DEF_SG_TABLESIZE,
.can_queue = SRP_CMD_SQ_SIZE,
.this_id = -1,
.cmd_per_lun = SRP_CMD_SQ_SIZE,
@@ -1750,6 +1763,7 @@ enum {
SRP_OPT_MAX_CMD_PER_LUN = 1 << 6,
SRP_OPT_IO_CLASS = 1 << 7,
SRP_OPT_INITIATOR_EXT = 1 << 8,
+ SRP_OPT_CMD_SG_ENTRIES = 1 << 9,
SRP_OPT_ALL = (SRP_OPT_ID_EXT |
SRP_OPT_IOC_GUID |
SRP_OPT_DGID |
@@ -1767,6 +1781,7 @@ static const match_table_t srp_opt_tokens = {
{ SRP_OPT_MAX_CMD_PER_LUN, "max_cmd_per_lun=%d" },
{ SRP_OPT_IO_CLASS, "io_class=%x" },
{ SRP_OPT_INITIATOR_EXT, "initiator_ext=%s" },
+ { SRP_OPT_CMD_SG_ENTRIES, "cmd_sg_entries=%u" },
{ SRP_OPT_ERR, NULL }
};

@@ -1894,6 +1909,14 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
kfree(p);
break;

+ case SRP_OPT_CMD_SG_ENTRIES:
+ if (match_int(args, &token) || token < 1 || token > 255) {
+ printk(KERN_WARNING PFX "bad max cmd_sg_entries parameter '%s'\n", p);
+ goto out;
+ }
+ target->cmd_sg_cnt = token;
+ break;
+
default:
printk(KERN_WARNING PFX "unknown parameter or missing value "
"'%s' in target creation request\n", p);
@@ -1932,17 +1955,18 @@ static ssize_t srp_create_target(struct device *dev,
if (!target_host)
return -ENOMEM;

- target_host->transportt = ib_srp_transport_template;
+ target_host->transportt = ib_srp_transport_template;
target_host->max_lun = SRP_MAX_LUN;
target_host->max_cmd_len = sizeof ((struct srp_cmd *) (void *) 0L)->cdb;

target = host_to_target(target_host);

- target->io_class = SRP_REV16A_IB_IO_CLASS;
- target->scsi_host = target_host;
- target->srp_host = host;
- target->lkey = host->srp_dev->mr->lkey;
- target->rkey = host->srp_dev->mr->rkey;
+ target->io_class = SRP_REV16A_IB_IO_CLASS;
+ target->scsi_host = target_host;
+ target->srp_host = host;
+ target->lkey = host->srp_dev->mr->lkey;
+ target->rkey = host->srp_dev->mr->rkey;
+ target->cmd_sg_cnt = cmd_sg_entries;

spin_lock_init(&target->lock);
INIT_LIST_HEAD(&target->free_tx);
@@ -1956,6 +1980,11 @@ static ssize_t srp_create_target(struct device *dev,
if (ret)
goto err;

+ target_host->sg_tablesize = target->cmd_sg_cnt;
+ target->max_iu_len = sizeof (struct srp_cmd) +
+ sizeof (struct srp_indirect_buf) +
+ target->cmd_sg_cnt * sizeof (struct srp_direct_buf);
+
ib_query_gid(host->srp_dev->dev, host->port, 0, &target->path.sgid);

shost_printk(KERN_DEBUG, target->scsi_host, PFX
@@ -2217,9 +2246,18 @@ static int __init srp_init_module(void)

BUILD_BUG_ON(FIELD_SIZEOF(struct ib_wc, wr_id) < sizeof(void *));

- if (srp_sg_tablesize > 255) {
- printk(KERN_WARNING PFX "Clamping srp_sg_tablesize to 255\n");
- srp_sg_tablesize = 255;
+ if (srp_sg_tablesize) {
+ printk(KERN_WARNING PFX "srp_sg_tablesize is deprecated, please use cmd_sg_entries\n");
+ if (!cmd_sg_entries)
+ cmd_sg_entries = srp_sg_tablesize;
+ }
+
+ if (!cmd_sg_entries)
+ cmd_sg_entries = SRP_DEF_SG_TABLESIZE;
+
+ if (cmd_sg_entries > 255) {
+ printk(KERN_WARNING PFX "Clamping cmd_sg_entries to 255\n");
+ cmd_sg_entries = 255;
}

ib_srp_transport_template =
@@ -2227,11 +2265,6 @@ static int __init srp_init_module(void)
if (!ib_srp_transport_template)
return -ENOMEM;

- srp_template.sg_tablesize = srp_sg_tablesize;
- srp_max_iu_len = (sizeof (struct srp_cmd) +
- sizeof (struct srp_indirect_buf) +
- srp_sg_tablesize * 16);
-
ret = class_register(&srp_class);
if (ret) {
printk(KERN_ERR PFX "couldn't register class infiniband_srp\n");
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 9dc6fc3..db39dbf 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -130,6 +130,8 @@ struct srp_target_port {
u32 lkey;
u32 rkey;
enum srp_target_state state;
+ unsigned int max_iu_len;
+ unsigned int cmd_sg_cnt;

/* Everything above this point is used in the hot path of
* command processing. Try to keep them packed into cachelines.