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* [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size
@ 2019-09-19  3:50 Honggang LI
  2019-09-19  3:50 ` [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available Honggang LI
  2019-09-20 16:11 ` [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Bart Van Assche
  0 siblings, 2 replies; 10+ messages in thread
From: Honggang LI @ 2019-09-19  3:50 UTC (permalink / raw)
  To: bvanassche, dledford, jgg; +Cc: linux-rdma, Honggang Li

From: Honggang Li <honli@redhat.com>

According to SRP specifications 'srp-r16a' and 'srp2r06',
IOControllerProfile attributes for SRP target port include
the maximum initiator to target IU size.

SRP connection daemons, such as srp_daemon, can get the value
from subnet manager. The SRP connection daemon can pass this
value to kernel.

This patch add parse function for it.

Upstream commit [1] enables the kernel parameter, 'use_imm_data',
by default. [1] also use (8 * 1024) as the default value for
kernel parameter 'max_imm_data'. With those default values, the
maximum initiator to target IU size will be 8260.

In case the SRPT modules, which include the in-tree 'ib_srpt.ko'
module, do not support SRP-2 'immediate data' feature, the default
maximum initiator to target IU size is significantly smaller than
8260. For 'ib_srpt.ko' module, which built from source before
[2], the default maximum initiator to target IU is 2116.

[1] introduces a regression issue for old srp target with default
kernel parameters, as the connection will be reject because of
too large maximum initiator to target IU size.

[1] commit 882981f4a411 ("RDMA/srp: Add support for immediate data")
[2] commit 5dabcd0456d7 ("RDMA/srpt: Add support for immediate data")

Signed-off-by: Honggang Li <honli@redhat.com>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 10 ++++++++++
 drivers/infiniband/ulp/srp/ib_srp.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index b5960351bec0..b829dab0df77 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -3411,6 +3411,7 @@ enum {
 	SRP_OPT_IP_SRC		= 1 << 15,
 	SRP_OPT_IP_DEST		= 1 << 16,
 	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
+	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
 };
 
 static unsigned int srp_opt_mandatory[] = {
@@ -3443,6 +3444,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_QUEUE_SIZE,		"queue_size=%d"		},
 	{ SRP_OPT_IP_SRC,		"src=%s"		},
 	{ SRP_OPT_IP_DEST,		"dest=%s"		},
+	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
 	{ SRP_OPT_ERR,			NULL 			}
 };
 
@@ -3736,6 +3738,14 @@ static int srp_parse_options(struct net *net, const char *buf,
 			target->tl_retry_count = token;
 			break;
 
+		case SRP_OPT_MAX_IT_IU_SIZE:
+			if (match_int(args, &token) || token < 0) {
+				pr_warn("bad maximum initiator to target IU size '%s'\n", p);
+				goto out;
+			}
+			target->max_it_iu_size = token;
+			break;
+
 		default:
 			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
 				p);
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index b2861cd2087a..105b2bc6aa2f 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -209,6 +209,7 @@ struct srp_target_port {
 	u32			ch_count;
 	u32			lkey;
 	enum srp_target_state	state;
+	uint32_t		max_it_iu_size;
 	unsigned int		cmd_sg_cnt;
 	unsigned int		indirect_size;
 	bool			allow_ext_sg;
-- 
2.21.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-19  3:50 [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Honggang LI
@ 2019-09-19  3:50 ` Honggang LI
  2019-09-20 16:18   ` Bart Van Assche
  2019-09-20 16:11 ` [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Bart Van Assche
  1 sibling, 1 reply; 10+ messages in thread
From: Honggang LI @ 2019-09-19  3:50 UTC (permalink / raw)
  To: bvanassche, dledford, jgg; +Cc: linux-rdma, Honggang Li

From: Honggang Li <honli@redhat.com>

The default maximum immediate size is too big for old srp clients,
which without immediate data support.

According to the SRP and SRP-2 specifications, the IOControllerProfile
attributes for SRP target ports contains the maximum initiator to target
iu length.

The maximum initiator to target iu length can be get from the subnet
manager, such as opensm and opafm. We should calculate the
max_it_iu_size instead of the default value, when remote maximum
initiator to target iu length available.

Signed-off-by: Honggang Li <honli@redhat.com>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index b829dab0df77..b3bf5d552de9 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -139,7 +139,7 @@ MODULE_PARM_DESC(use_imm_data,
 
 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.");
+MODULE_PARM_DESC(max_imm_data, "Maximum immediate data size if max_it_iu_size has not been specified.");
 
 static unsigned ch_count;
 module_param(ch_count, uint, 0444);
@@ -1362,15 +1362,23 @@ 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, bool use_imm_data)
+static uint32_t srp_max_it_iu_len(int cmd_sg_cnt, bool use_imm_data,
+				  uint32_t max_it_iu_size)
 {
 	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);
+	if (use_imm_data) {
+		if (max_it_iu_size == 0) {
+			max_iu_len = max(max_iu_len,
+			   SRP_IMM_DATA_OFFSET + srp_max_imm_data);
+		} else {
+			max_iu_len = max_it_iu_size;
+		}
+	}
+
+	pr_debug("max_iu_len = %d\n", max_iu_len);
 
 	return max_iu_len;
 }
@@ -1389,7 +1397,8 @@ 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,
-						srp_use_imm_data);
+						srp_use_imm_data,
+						target->max_it_iu_size);
 	int i, j, ret = 0;
 	bool multich = false;
 
@@ -2538,7 +2547,8 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
 		ch->req_lim       = be32_to_cpu(lrsp->req_lim_delta);
 		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);
+						      ch->use_imm_data,
+						      target->max_it_iu_size);
 		WARN_ON_ONCE(ch->max_it_iu_len >
 			     be32_to_cpu(lrsp->max_it_iu_len));
 
@@ -3897,7 +3907,9 @@ 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, srp_use_imm_data);
+	max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
+				       srp_use_imm_data,
+				       target->max_it_iu_size);
 
 	INIT_WORK(&target->tl_err_work, srp_tl_err_work);
 	INIT_WORK(&target->remove_work, srp_remove_work);
-- 
2.21.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size
  2019-09-19  3:50 [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Honggang LI
  2019-09-19  3:50 ` [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available Honggang LI
@ 2019-09-20 16:11 ` Bart Van Assche
  2019-09-23  3:30   ` Honggang LI
  1 sibling, 1 reply; 10+ messages in thread
From: Bart Van Assche @ 2019-09-20 16:11 UTC (permalink / raw)
  To: Honggang LI, dledford, jgg; +Cc: linux-rdma

On 9/18/19 8:50 PM, Honggang LI wrote:
> diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
> index b5960351bec0..b829dab0df77 100644
> --- a/drivers/infiniband/ulp/srp/ib_srp.c
> +++ b/drivers/infiniband/ulp/srp/ib_srp.c
> @@ -3411,6 +3411,7 @@ enum {
>   	SRP_OPT_IP_SRC		= 1 << 15,
>   	SRP_OPT_IP_DEST		= 1 << 16,
>   	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
> +	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
>   };
>   
>   static unsigned int srp_opt_mandatory[] = {
> @@ -3443,6 +3444,7 @@ static const match_table_t srp_opt_tokens = {
>   	{ SRP_OPT_QUEUE_SIZE,		"queue_size=%d"		},
>   	{ SRP_OPT_IP_SRC,		"src=%s"		},
>   	{ SRP_OPT_IP_DEST,		"dest=%s"		},
> +	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
>   	{ SRP_OPT_ERR,			NULL 			}
>   };
>   
> @@ -3736,6 +3738,14 @@ static int srp_parse_options(struct net *net, const char *buf,
>   			target->tl_retry_count = token;
>   			break;
>   
> +		case SRP_OPT_MAX_IT_IU_SIZE:
> +			if (match_int(args, &token) || token < 0) {
> +				pr_warn("bad maximum initiator to target IU size '%s'\n", p);
> +				goto out;
> +			}
> +			target->max_it_iu_size = token;
> +			break;
> +
>   		default:
>   			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
>   				p);
> diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
> index b2861cd2087a..105b2bc6aa2f 100644
> --- a/drivers/infiniband/ulp/srp/ib_srp.h
> +++ b/drivers/infiniband/ulp/srp/ib_srp.h
> @@ -209,6 +209,7 @@ struct srp_target_port {
>   	u32			ch_count;
>   	u32			lkey;
>   	enum srp_target_state	state;
> +	uint32_t		max_it_iu_size;
>   	unsigned int		cmd_sg_cnt;
>   	unsigned int		indirect_size;
>   	bool			allow_ext_sg;
> 

Something I forgot to mention last time: since this patch adds a new 
login parameter Documentation/ABI/stable/sysfs-driver-ib_srp should be 
updated. I don't have a strong opinion about whether that should happen 
through a separate patch or not. Since the code changes look fine to me:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-19  3:50 ` [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available Honggang LI
@ 2019-09-20 16:18   ` Bart Van Assche
  2019-09-23  3:33     ` Honggang LI
  0 siblings, 1 reply; 10+ messages in thread
From: Bart Van Assche @ 2019-09-20 16:18 UTC (permalink / raw)
  To: Honggang LI, dledford, jgg; +Cc: linux-rdma

On 9/18/19 8:50 PM, Honggang LI wrote:
> From: Honggang Li <honli@redhat.com>
> 
> The default maximum immediate size is too big for old srp clients,
> which without immediate data support.
         ^^^^^^^
         do not?
> 
> According to the SRP and SRP-2 specifications, the IOControllerProfile
> attributes for SRP target ports contains the maximum initiator to target
> iu length.
> 
> The maximum initiator to target iu length can be get from the subnet
                                                    ^^^
                                          retrieved? obtained?
> manager, such as opensm and opafm. We should calculate the
   ^^^^^^^

Are you sure that information comes from the subnet manager?
Isn't the LID passed to get_ioc_prof() in the srp_daemon the LID of the 
SRP target?

Anyway, since the code changes look fine to me, feel free to add:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size
  2019-09-20 16:11 ` [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Bart Van Assche
@ 2019-09-23  3:30   ` Honggang LI
  2019-09-23 15:12     ` Bart Van Assche
  0 siblings, 1 reply; 10+ messages in thread
From: Honggang LI @ 2019-09-23  3:30 UTC (permalink / raw)
  To: Bart Van Assche; +Cc: dledford, jgg, linux-rdma

On Fri, Sep 20, 2019 at 09:11:06AM -0700, Bart Van Assche wrote:
> 
> Something I forgot to mention last time: since this patch adds a new login
> parameter Documentation/ABI/stable/sysfs-driver-ib_srp should be updated. I

I will submit a new patch to update 'sysfs-driver-ib_srp'.

thanks

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-20 16:18   ` Bart Van Assche
@ 2019-09-23  3:33     ` Honggang LI
  2019-09-23 15:10       ` Bart Van Assche
  0 siblings, 1 reply; 10+ messages in thread
From: Honggang LI @ 2019-09-23  3:33 UTC (permalink / raw)
  To: Bart Van Assche; +Cc: dledford, jgg, linux-rdma

On Fri, Sep 20, 2019 at 09:18:49AM -0700, Bart Van Assche wrote:
> On 9/18/19 8:50 PM, Honggang LI wrote:
> > From: Honggang Li <honli@redhat.com>
> > 
> > The default maximum immediate size is too big for old srp clients,
> > which without immediate data support.
>         ^^^^^^^
>         do not?

OK, will fix it.

> > 
> > According to the SRP and SRP-2 specifications, the IOControllerProfile
> > attributes for SRP target ports contains the maximum initiator to target
> > iu length.
> > 
> > The maximum initiator to target iu length can be get from the subnet
>                                                    ^^^
>                                          retrieved? obtained?

OK, will replace it with 'retrieved'.

> > manager, such as opensm and opafm. We should calculate the
>   ^^^^^^^
> 
> Are you sure that information comes from the subnet manager?
> Isn't the LID passed to get_ioc_prof() in the srp_daemon the LID of the SRP
> target?

Yes, you are right. But srp_daemon/get_ioc_prof() send MAD packet
to subnet manager to obtain the maximum initiator to target iu length.

> 
> Anyway, since the code changes look fine to me, feel free to add:
> 
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-23  3:33     ` Honggang LI
@ 2019-09-23 15:10       ` Bart Van Assche
  2019-09-27 17:18         ` Honggang LI
  0 siblings, 1 reply; 10+ messages in thread
From: Bart Van Assche @ 2019-09-23 15:10 UTC (permalink / raw)
  To: Honggang LI; +Cc: dledford, jgg, linux-rdma

On 9/22/19 8:33 PM, Honggang LI wrote:
> On Fri, Sep 20, 2019 at 09:18:49AM -0700, Bart Van Assche wrote:
>> On 9/18/19 8:50 PM, Honggang LI wrote:
>>> The maximum initiator to target iu length can be get from the subnet
>>                                                     ^^^
>>                                           retrieved? obtained?
> 
> OK, will replace it with 'retrieved'.
> 
>>> manager, such as opensm and opafm. We should calculate the
>>    ^^^^^^^
>>
>> Are you sure that information comes from the subnet manager?
>> Isn't the LID passed to get_ioc_prof() in the srp_daemon the LID of the SRP
>> target?
> 
> Yes, you are right. But srp_daemon/get_ioc_prof() send MAD packet
> to subnet manager to obtain the maximum initiator to target iu length.
  I do not agree that the maximum initiator to target IU length comes 
from the subnet manager. This is how I think the srp_daemon works:
1. The srp_daemon process sends a query to the subnet manager and asks
    the subnet manager to report all IB ports that support device
    management.
2. The subnet manager sends back information about all ports that
    support device management (struct srp_sa_port_info_rec).
3. The srp_daemon sends a query to the SRP target(s) to retrieve the
    IOUnitInfo (struct srp_dm_iou_info) and IOControllerProfile
    (struct srp_dm_ioc_prof). The maximum initiator to target IU length
    is present in that data structure (srp_dm_ioc_prof.send_size).

Bart.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size
  2019-09-23  3:30   ` Honggang LI
@ 2019-09-23 15:12     ` Bart Van Assche
  0 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-23 15:12 UTC (permalink / raw)
  To: Honggang LI; +Cc: dledford, jgg, linux-rdma

On 9/22/19 8:30 PM, Honggang LI wrote:
> On Fri, Sep 20, 2019 at 09:11:06AM -0700, Bart Van Assche wrote:
>>
>> Something I forgot to mention last time: since this patch adds a new login
>> parameter Documentation/ABI/stable/sysfs-driver-ib_srp should be updated. I
> 
> I will submit a new patch to update 'sysfs-driver-ib_srp'.

Thanks!

Bart.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-23 15:10       ` Bart Van Assche
@ 2019-09-27 17:18         ` Honggang LI
  2019-09-27 17:24           ` Bart Van Assche
  0 siblings, 1 reply; 10+ messages in thread
From: Honggang LI @ 2019-09-27 17:18 UTC (permalink / raw)
  To: Bart Van Assche; +Cc: dledford, jgg, linux-rdma

On Mon, Sep 23, 2019 at 08:10:48AM -0700, Bart Van Assche wrote:
> On 9/22/19 8:33 PM, Honggang LI wrote:
> > On Fri, Sep 20, 2019 at 09:18:49AM -0700, Bart Van Assche wrote:
> > > On 9/18/19 8:50 PM, Honggang LI wrote:
> > > > The maximum initiator to target iu length can be get from the subnet
> > >                                                     ^^^
> > >                                           retrieved? obtained?
> > 
> > OK, will replace it with 'retrieved'.
> > 
> > > > manager, such as opensm and opafm. We should calculate the
> > >    ^^^^^^^
> > > 
> > > Are you sure that information comes from the subnet manager?
> > > Isn't the LID passed to get_ioc_prof() in the srp_daemon the LID of the SRP
> > > target?
> > 
> > Yes, you are right. But srp_daemon/get_ioc_prof() send MAD packet
> > to subnet manager to obtain the maximum initiator to target iu length.
>  I do not agree that the maximum initiator to target IU length comes from
> the subnet manager. This is how I think the srp_daemon works:
> 1. The srp_daemon process sends a query to the subnet manager and asks
>    the subnet manager to report all IB ports that support device
>    management.
> 2. The subnet manager sends back information about all ports that
>    support device management (struct srp_sa_port_info_rec).
> 3. The srp_daemon sends a query to the SRP target(s) to retrieve the
>    IOUnitInfo (struct srp_dm_iou_info) and IOControllerProfile
>    (struct srp_dm_ioc_prof). The maximum initiator to target IU length
>    is present in that data structure (srp_dm_ioc_prof.send_size).

Yes, your description is more accurate.

[1] "The maximum initiator to target iu length can be retrieved from the subnet
manager, such as opensm and opafm."

[2] "The maximum initiator to target iu length can be obtained by sending
MAD packets to query subnet manager port and SRP target ports."

How about replacing sentence [1] with [2] in commit message?

thanks

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available
  2019-09-27 17:18         ` Honggang LI
@ 2019-09-27 17:24           ` Bart Van Assche
  0 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-27 17:24 UTC (permalink / raw)
  To: Honggang LI; +Cc: dledford, jgg, linux-rdma

On 9/27/19 10:18 AM, Honggang LI wrote:
> On Mon, Sep 23, 2019 at 08:10:48AM -0700, Bart Van Assche wrote:
>> On 9/22/19 8:33 PM, Honggang LI wrote:
>>> On Fri, Sep 20, 2019 at 09:18:49AM -0700, Bart Van Assche wrote:
>>>> On 9/18/19 8:50 PM, Honggang LI wrote:
>>>>> The maximum initiator to target iu length can be get from the subnet
>>>>                                                      ^^^
>>>>                                            retrieved? obtained?
>>>
>>> OK, will replace it with 'retrieved'.
>>>
>>>>> manager, such as opensm and opafm. We should calculate the
>>>>     ^^^^^^^
>>>>
>>>> Are you sure that information comes from the subnet manager?
>>>> Isn't the LID passed to get_ioc_prof() in the srp_daemon the LID of the SRP
>>>> target?
>>>
>>> Yes, you are right. But srp_daemon/get_ioc_prof() send MAD packet
>>> to subnet manager to obtain the maximum initiator to target iu length.
>>   I do not agree that the maximum initiator to target IU length comes from
>> the subnet manager. This is how I think the srp_daemon works:
>> 1. The srp_daemon process sends a query to the subnet manager and asks
>>     the subnet manager to report all IB ports that support device
>>     management.
>> 2. The subnet manager sends back information about all ports that
>>     support device management (struct srp_sa_port_info_rec).
>> 3. The srp_daemon sends a query to the SRP target(s) to retrieve the
>>     IOUnitInfo (struct srp_dm_iou_info) and IOControllerProfile
>>     (struct srp_dm_ioc_prof). The maximum initiator to target IU length
>>     is present in that data structure (srp_dm_ioc_prof.send_size).
> 
> Yes, your description is more accurate.
> 
> [1] "The maximum initiator to target iu length can be retrieved from the subnet
> manager, such as opensm and opafm."
> 
> [2] "The maximum initiator to target iu length can be obtained by sending
> MAD packets to query subnet manager port and SRP target ports."
> 
> How about replacing sentence [1] with [2] in commit message?

[2] sounds a little bit confusing to me but I think we have already 
spent way too much time on discussing the commit message, so I'm fine 
with [2].

Bart.


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2019-09-27 17:24 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-19  3:50 [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Honggang LI
2019-09-19  3:50 ` [patch v3 2/2] RDMA/srp: calculate max_it_iu_size if remote max_it_iu length available Honggang LI
2019-09-20 16:18   ` Bart Van Assche
2019-09-23  3:33     ` Honggang LI
2019-09-23 15:10       ` Bart Van Assche
2019-09-27 17:18         ` Honggang LI
2019-09-27 17:24           ` Bart Van Assche
2019-09-20 16:11 ` [patch v3 1/2] RDMA/srp: Add parse function for maximum initiator to target IU size Bart Van Assche
2019-09-23  3:30   ` Honggang LI
2019-09-23 15:12     ` Bart Van Assche

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