diff mbox series

[1/1] IB/isert: add module param to set sg_tablesize for IO cmd

Message ID 20201011090608.159333-1-mgurtovoy@nvidia.com (mailing list archive)
State Superseded
Headers show
Series [1/1] IB/isert: add module param to set sg_tablesize for IO cmd | expand

Commit Message

Max Gurtovoy Oct. 11, 2020, 9:06 a.m. UTC 
From: Max Gurtovoy <maxg@mellanox.com>

Currently, iser target support max IO size of 16MiB by default. For some
adapters, allocating this amount of resources might reduce the total
number of possible connections that can be created. For those adapters,
it's preferred to reduce the max IO size to be able to create more
connections. Since there is no handshake procedure for max IO size in
iser protocol, set the default max IO size to 1MiB and add a module
parameter for enabling the option to control it for suitable adapters.

Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 27 ++++++++++++++++++++++++-
 drivers/infiniband/ulp/isert/ib_isert.h |  6 ++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

Comments

Max Gurtovoy Oct. 13, 2020, 5:43 p.m. UTC | #1 
Krishna,

did this patch fix the issue you reported ?


On 10/11/2020 12:06 PM, Max Gurtovoy wrote:
> From: Max Gurtovoy <maxg@mellanox.com>
>
> Currently, iser target support max IO size of 16MiB by default. For some
> adapters, allocating this amount of resources might reduce the total
> number of possible connections that can be created. For those adapters,
> it's preferred to reduce the max IO size to be able to create more
> connections. Since there is no handshake procedure for max IO size in
> iser protocol, set the default max IO size to 1MiB and add a module
> parameter for enabling the option to control it for suitable adapters.
>
> Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
> Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
> ---
>   drivers/infiniband/ulp/isert/ib_isert.c | 27 ++++++++++++++++++++++++-
>   drivers/infiniband/ulp/isert/ib_isert.h |  6 ++++++
>   2 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
> index 695f701dc43d..5a47f1bbca96 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.c
> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> @@ -28,6 +28,18 @@ static int isert_debug_level;
>   module_param_named(debug_level, isert_debug_level, int, 0644);
>   MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:0)");
>   
> +static int isert_sg_tablesize_set(const char *val,
> +				  const struct kernel_param *kp);
> +static const struct kernel_param_ops sg_tablesize_ops = {
> +	.set = isert_sg_tablesize_set,
> +	.get = param_get_int,
> +};
> +
> +static int isert_sg_tablesize = ISCSI_ISER_SG_TABLESIZE;
> +module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
> +MODULE_PARM_DESC(sg_tablesize,
> +		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 256, max: 4096)");
> +
>   static DEFINE_MUTEX(device_list_mutex);
>   static LIST_HEAD(device_list);
>   static struct workqueue_struct *isert_comp_wq;
> @@ -47,6 +59,19 @@ static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc);
>   static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
>   static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);
>   
> +static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp)
> +{
> +	int n = 0, ret;
> +
> +	ret = kstrtoint(val, 10, &n);
> +	if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
> +	    n > ISCSI_ISER_MAX_SG_TABLESIZE)
> +		return -EINVAL;
> +
> +	return param_set_int(val, kp);
> +}
> +
> +
>   static inline bool
>   isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
>   {
> @@ -101,7 +126,7 @@ isert_create_qp(struct isert_conn *isert_conn,
>   	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
>   	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
>   	factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
> -				   ISCSI_ISER_MAX_SG_TABLESIZE);
> +				   isert_sg_tablesize);
>   	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
>   	attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
>   	attr.cap.max_recv_sge = 1;
> diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
> index 7fee4a65e181..90ef215bf755 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.h
> +++ b/drivers/infiniband/ulp/isert/ib_isert.h
> @@ -65,6 +65,12 @@
>    */
>   #define ISER_RX_SIZE		(ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
>   
> +/* Default I/O size is 1MB */
> +#define ISCSI_ISER_SG_TABLESIZE 256
> +
> +/* Minimum I/O size is 512KB */
> +#define ISCSI_ISER_MIN_SG_TABLESIZE 128
> +
>   /* Maximum support is 16MB I/O size */
>   #define ISCSI_ISER_MAX_SG_TABLESIZE	4096
>
Sagi Grimberg Oct. 13, 2020, 10:21 p.m. UTC | #2 
On 10/11/20 2:06 AM, Max Gurtovoy wrote:
> From: Max Gurtovoy <maxg@mellanox.com>
> 
> Currently, iser target support max IO size of 16MiB by default. For some
> adapters, allocating this amount of resources might reduce the total
> number of possible connections that can be created. For those adapters,
> it's preferred to reduce the max IO size to be able to create more
> connections. Since there is no handshake procedure for max IO size in
> iser protocol, set the default max IO size to 1MiB and add a module
> parameter for enabling the option to control it for suitable adapters.
> 
> Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
> Signed-off-by: Max Gurtovoy <maxg@mellanox.com>

You can add a "Fixes:" tag to help it get to stable.

> ---
>   drivers/infiniband/ulp/isert/ib_isert.c | 27 ++++++++++++++++++++++++-
>   drivers/infiniband/ulp/isert/ib_isert.h |  6 ++++++
>   2 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
> index 695f701dc43d..5a47f1bbca96 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.c
> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> @@ -28,6 +28,18 @@ static int isert_debug_level;
>   module_param_named(debug_level, isert_debug_level, int, 0644);
>   MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:0)");
>   
> +static int isert_sg_tablesize_set(const char *val,
> +				  const struct kernel_param *kp);
> +static const struct kernel_param_ops sg_tablesize_ops = {
> +	.set = isert_sg_tablesize_set,
> +	.get = param_get_int,
> +};
> +
> +static int isert_sg_tablesize = ISCSI_ISER_SG_TABLESIZE;
> +module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
> +MODULE_PARM_DESC(sg_tablesize,
> +		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 256, max: 4096)");
> +
>   static DEFINE_MUTEX(device_list_mutex);
>   static LIST_HEAD(device_list);
>   static struct workqueue_struct *isert_comp_wq;
> @@ -47,6 +59,19 @@ static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc);
>   static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
>   static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);
>   
> +static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp)
> +{
> +	int n = 0, ret;
> +
> +	ret = kstrtoint(val, 10, &n);
> +	if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
> +	    n > ISCSI_ISER_MAX_SG_TABLESIZE)
> +		return -EINVAL;
> +
> +	return param_set_int(val, kp);
> +}
> +
> +
>   static inline bool
>   isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
>   {
> @@ -101,7 +126,7 @@ isert_create_qp(struct isert_conn *isert_conn,
>   	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
>   	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
>   	factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
> -				   ISCSI_ISER_MAX_SG_TABLESIZE);
> +				   isert_sg_tablesize);
>   	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
>   	attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
>   	attr.cap.max_recv_sge = 1;
> diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
> index 7fee4a65e181..90ef215bf755 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.h
> +++ b/drivers/infiniband/ulp/isert/ib_isert.h
> @@ -65,6 +65,12 @@
>    */
>   #define ISER_RX_SIZE		(ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
>   
> +/* Default I/O size is 1MB */
> +#define ISCSI_ISER_SG_TABLESIZE 256

Maybe name it ISCSI_ISER_DEF_SG_TABLESIZE

Otherwise,

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Krishnamraju Eraparaju Oct. 13, 2020, 11:48 p.m. UTC | #3 
On Tuesday, October 10/13/20, 2020 at 20:43:03 +0300, Max Gurtovoy wrote:
> Krishna,
> 
> did this patch fix the issue you reported ?

With this patch applied, I don't see the reported issue anymore.
Thanks for the patch!



> 
> 
> On 10/11/2020 12:06 PM, Max Gurtovoy wrote:
> >From: Max Gurtovoy <maxg@mellanox.com>
> >
> >Currently, iser target support max IO size of 16MiB by default. For some
> >adapters, allocating this amount of resources might reduce the total
> >number of possible connections that can be created. For those adapters,
> >it's preferred to reduce the max IO size to be able to create more
> >connections. Since there is no handshake procedure for max IO size in
> >iser protocol, set the default max IO size to 1MiB and add a module
> >parameter for enabling the option to control it for suitable adapters.
> >
> >Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
> >Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
> >---
> >  drivers/infiniband/ulp/isert/ib_isert.c | 27 ++++++++++++++++++++++++-
> >  drivers/infiniband/ulp/isert/ib_isert.h |  6 ++++++
> >  2 files changed, 32 insertions(+), 1 deletion(-)
> >
> >diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
> >index 695f701dc43d..5a47f1bbca96 100644
> >--- a/drivers/infiniband/ulp/isert/ib_isert.c
> >+++ b/drivers/infiniband/ulp/isert/ib_isert.c
> >@@ -28,6 +28,18 @@ static int isert_debug_level;
> >  module_param_named(debug_level, isert_debug_level, int, 0644);
> >  MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:0)");
> >+static int isert_sg_tablesize_set(const char *val,
> >+				  const struct kernel_param *kp);
> >+static const struct kernel_param_ops sg_tablesize_ops = {
> >+	.set = isert_sg_tablesize_set,
> >+	.get = param_get_int,
> >+};
> >+
> >+static int isert_sg_tablesize = ISCSI_ISER_SG_TABLESIZE;
> >+module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
> >+MODULE_PARM_DESC(sg_tablesize,
> >+		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 256, max: 4096)");
> >+
> >  static DEFINE_MUTEX(device_list_mutex);
> >  static LIST_HEAD(device_list);
> >  static struct workqueue_struct *isert_comp_wq;
> >@@ -47,6 +59,19 @@ static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc);
> >  static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
> >  static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);
> >+static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp)
> >+{
> >+	int n = 0, ret;
> >+
> >+	ret = kstrtoint(val, 10, &n);
> >+	if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
> >+	    n > ISCSI_ISER_MAX_SG_TABLESIZE)
> >+		return -EINVAL;
> >+
> >+	return param_set_int(val, kp);
> >+}
> >+
> >+
> >  static inline bool
> >  isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
> >  {
> >@@ -101,7 +126,7 @@ isert_create_qp(struct isert_conn *isert_conn,
> >  	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
> >  	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
> >  	factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
> >-				   ISCSI_ISER_MAX_SG_TABLESIZE);
> >+				   isert_sg_tablesize);
> >  	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
> >  	attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
> >  	attr.cap.max_recv_sge = 1;
> >diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
> >index 7fee4a65e181..90ef215bf755 100644
> >--- a/drivers/infiniband/ulp/isert/ib_isert.h
> >+++ b/drivers/infiniband/ulp/isert/ib_isert.h
> >@@ -65,6 +65,12 @@
> >   */
> >  #define ISER_RX_SIZE		(ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
> >+/* Default I/O size is 1MB */
> >+#define ISCSI_ISER_SG_TABLESIZE 256
> >+
> >+/* Minimum I/O size is 512KB */
> >+#define ISCSI_ISER_MIN_SG_TABLESIZE 128
> >+
> >  /* Maximum support is 16MB I/O size */
> >  #define ISCSI_ISER_MAX_SG_TABLESIZE	4096
Max Gurtovoy Oct. 14, 2020, 12:11 a.m. UTC | #4 
On 10/14/2020 1:21 AM, Sagi Grimberg wrote:
>
>
> On 10/11/20 2:06 AM, Max Gurtovoy wrote:
>> From: Max Gurtovoy <maxg@mellanox.com>
>>
>> Currently, iser target support max IO size of 16MiB by default. For some
>> adapters, allocating this amount of resources might reduce the total
>> number of possible connections that can be created. For those adapters,
>> it's preferred to reduce the max IO size to be able to create more
>> connections. Since there is no handshake procedure for max IO size in
>> iser protocol, set the default max IO size to 1MiB and add a module
>> parameter for enabling the option to control it for suitable adapters.
>>
>> Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
>> Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
>
> You can add a "Fixes:" tag to help it get to stable.

But the previous commit is not buggy. It reveals some resource lacking 
in some HCAs.

I can add it if needed.

>
>> ---
>>   drivers/infiniband/ulp/isert/ib_isert.c | 27 ++++++++++++++++++++++++-
>>   drivers/infiniband/ulp/isert/ib_isert.h |  6 ++++++
>>   2 files changed, 32 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c 
>> b/drivers/infiniband/ulp/isert/ib_isert.c
>> index 695f701dc43d..5a47f1bbca96 100644
>> --- a/drivers/infiniband/ulp/isert/ib_isert.c
>> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
>> @@ -28,6 +28,18 @@ static int isert_debug_level;
>>   module_param_named(debug_level, isert_debug_level, int, 0644);
>>   MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 
>> (default:0)");
>>   +static int isert_sg_tablesize_set(const char *val,
>> +                  const struct kernel_param *kp);
>> +static const struct kernel_param_ops sg_tablesize_ops = {
>> +    .set = isert_sg_tablesize_set,
>> +    .get = param_get_int,
>> +};
>> +
>> +static int isert_sg_tablesize = ISCSI_ISER_SG_TABLESIZE;
>> +module_param_cb(sg_tablesize, &sg_tablesize_ops, 
>> &isert_sg_tablesize, 0644);
>> +MODULE_PARM_DESC(sg_tablesize,
>> +         "Number of gather/scatter entries in a single scsi command, 
>> should >= 128 (default: 256, max: 4096)");
>> +
>>   static DEFINE_MUTEX(device_list_mutex);
>>   static LIST_HEAD(device_list);
>>   static struct workqueue_struct *isert_comp_wq;
>> @@ -47,6 +59,19 @@ static void isert_send_done(struct ib_cq *cq, 
>> struct ib_wc *wc);
>>   static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
>>   static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);
>>   +static int isert_sg_tablesize_set(const char *val, const struct 
>> kernel_param *kp)
>> +{
>> +    int n = 0, ret;
>> +
>> +    ret = kstrtoint(val, 10, &n);
>> +    if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
>> +        n > ISCSI_ISER_MAX_SG_TABLESIZE)
>> +        return -EINVAL;
>> +
>> +    return param_set_int(val, kp);
>> +}
>> +
>> +
>>   static inline bool
>>   isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
>>   {
>> @@ -101,7 +126,7 @@ isert_create_qp(struct isert_conn *isert_conn,
>>       attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
>>       attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
>>       factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
>> -                   ISCSI_ISER_MAX_SG_TABLESIZE);
>> +                   isert_sg_tablesize);
>>       attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
>>       attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
>>       attr.cap.max_recv_sge = 1;
>> diff --git a/drivers/infiniband/ulp/isert/ib_isert.h 
>> b/drivers/infiniband/ulp/isert/ib_isert.h
>> index 7fee4a65e181..90ef215bf755 100644
>> --- a/drivers/infiniband/ulp/isert/ib_isert.h
>> +++ b/drivers/infiniband/ulp/isert/ib_isert.h
>> @@ -65,6 +65,12 @@
>>    */
>>   #define ISER_RX_SIZE        (ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
>>   +/* Default I/O size is 1MB */
>> +#define ISCSI_ISER_SG_TABLESIZE 256
>
> Maybe name it ISCSI_ISER_DEF_SG_TABLESIZE

ok


>
> Otherwise,
>
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
diff mbox series

Patch

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 695f701dc43d..5a47f1bbca96 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -28,6 +28,18 @@  static int isert_debug_level;
 module_param_named(debug_level, isert_debug_level, int, 0644);
 MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:0)");
 
+static int isert_sg_tablesize_set(const char *val,
+				  const struct kernel_param *kp);
+static const struct kernel_param_ops sg_tablesize_ops = {
+	.set = isert_sg_tablesize_set,
+	.get = param_get_int,
+};
+
+static int isert_sg_tablesize = ISCSI_ISER_SG_TABLESIZE;
+module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
+MODULE_PARM_DESC(sg_tablesize,
+		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 256, max: 4096)");
+
 static DEFINE_MUTEX(device_list_mutex);
 static LIST_HEAD(device_list);
 static struct workqueue_struct *isert_comp_wq;
@@ -47,6 +59,19 @@  static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc);
 static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
 static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);
 
+static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp)
+{
+	int n = 0, ret;
+
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
+	    n > ISCSI_ISER_MAX_SG_TABLESIZE)
+		return -EINVAL;
+
+	return param_set_int(val, kp);
+}
+
+
 static inline bool
 isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
 {
@@ -101,7 +126,7 @@  isert_create_qp(struct isert_conn *isert_conn,
 	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
 	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
 	factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
-				   ISCSI_ISER_MAX_SG_TABLESIZE);
+				   isert_sg_tablesize);
 	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
 	attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
 	attr.cap.max_recv_sge = 1;
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 7fee4a65e181..90ef215bf755 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -65,6 +65,12 @@ 
  */
 #define ISER_RX_SIZE		(ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
 
+/* Default I/O size is 1MB */
+#define ISCSI_ISER_SG_TABLESIZE 256
+
+/* Minimum I/O size is 512KB */
+#define ISCSI_ISER_MIN_SG_TABLESIZE 128
+
 /* Maximum support is 16MB I/O size */
 #define ISCSI_ISER_MAX_SG_TABLESIZE	4096