2024-03-25 16:04:40

by Yihang Li

[permalink] [raw]
Subject: [PATCH] scsi: libsas: Add SMP request allocation handler callback

This series [1] reducing the kmalloc() minimum alignment on arm64 to 8
(from 128).

The hisi_sas has special requirements on the memory address alignment
(must be 16-byte-aligned) of the command request frame, so add a SMP
request allocation callback and fill it in for the hisi_sas driver.

Link: https://lkml.kernel.org/r/[email protected] [1]
Signed-off-by: Yihang Li <[email protected]>
---
drivers/scsi/hisi_sas/hisi_sas_main.c | 14 ++++++++++++
drivers/scsi/libsas/sas_expander.c | 31 ++++++++++++++++++---------
include/scsi/libsas.h | 3 +++
3 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 097dfe4b620d..40329558d435 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -2031,6 +2031,19 @@ static int hisi_sas_write_gpio(struct sas_ha_struct *sha, u8 reg_type,
reg_index, reg_count, write_data);
}

+static void *hisi_sas_alloc_smp_req(int size)
+{
+ u8 *p;
+
+ /* The address must be 16-byte-aligned. */
+ size = ALIGN(size, ARCH_DMA_MINALIGN);
+ p = kzalloc(size, GFP_KERNEL);
+ if (p)
+ p[0] = SMP_REQUEST;
+
+ return p;
+}
+
static void hisi_sas_phy_disconnected(struct hisi_sas_phy *phy)
{
struct asd_sas_phy *sas_phy = &phy->sas_phy;
@@ -2130,6 +2143,7 @@ static struct sas_domain_function_template hisi_sas_transport_ops = {
.lldd_write_gpio = hisi_sas_write_gpio,
.lldd_tmf_aborted = hisi_sas_tmf_aborted,
.lldd_abort_timeout = hisi_sas_internal_abort_timeout,
+ .lldd_alloc_smp_req = hisi_sas_alloc_smp_req,
};

void hisi_sas_init_mem(struct hisi_hba *hisi_hba)
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index a2204674b680..0fd0507f7fc6 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -141,6 +141,17 @@ static inline void *alloc_smp_req(int size)
return p;
}

+static void *sas_alloc_smp_req(struct domain_device *dev, int size)
+{
+ struct sas_internal *i =
+ to_sas_internal(dev->port->ha->shost->transportt);
+
+ if (i->dft->lldd_alloc_smp_req)
+ return i->dft->lldd_alloc_smp_req(size);
+
+ return alloc_smp_req(size);
+}
+
static inline void *alloc_smp_resp(int size)
{
return kzalloc(size, GFP_KERNEL);
@@ -377,7 +388,7 @@ int sas_ex_phy_discover(struct domain_device *dev, int single)
u8 *disc_req;
struct smp_disc_resp *disc_resp;

- disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
+ disc_req = sas_alloc_smp_req(dev, DISCOVER_REQ_SIZE);
if (!disc_req)
return -ENOMEM;

@@ -440,7 +451,7 @@ static int sas_ex_general(struct domain_device *dev)
int res;
int i;

- rg_req = alloc_smp_req(RG_REQ_SIZE);
+ rg_req = sas_alloc_smp_req(dev, RG_REQ_SIZE);
if (!rg_req)
return -ENOMEM;

@@ -519,7 +530,7 @@ static int sas_ex_manuf_info(struct domain_device *dev)
u8 *mi_resp;
int res;

- mi_req = alloc_smp_req(MI_REQ_SIZE);
+ mi_req = sas_alloc_smp_req(dev, MI_REQ_SIZE);
if (!mi_req)
return -ENOMEM;

@@ -560,7 +571,7 @@ int sas_smp_phy_control(struct domain_device *dev, int phy_id,
u8 *pc_resp;
int res;

- pc_req = alloc_smp_req(PC_REQ_SIZE);
+ pc_req = sas_alloc_smp_req(dev, PC_REQ_SIZE);
if (!pc_req)
return -ENOMEM;

@@ -642,7 +653,7 @@ int sas_smp_get_phy_events(struct sas_phy *phy)
struct sas_rphy *rphy = dev_to_rphy(phy->dev.parent);
struct domain_device *dev = sas_find_dev_by_rphy(rphy);

- req = alloc_smp_req(RPEL_REQ_SIZE);
+ req = sas_alloc_smp_req(dev, RPEL_REQ_SIZE);
if (!req)
return -ENOMEM;

@@ -682,7 +693,7 @@ int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
struct smp_rps_resp *rps_resp)
{
int res;
- u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE);
+ u8 *rps_req = sas_alloc_smp_req(dev, RPS_REQ_SIZE);
u8 *resp = (u8 *)rps_resp;

if (!rps_req)
@@ -1344,7 +1355,7 @@ static int sas_configure_present(struct domain_device *dev, int phy_id,
*present = 0;
*index = 0;

- rri_req = alloc_smp_req(RRI_REQ_SIZE);
+ rri_req = sas_alloc_smp_req(dev, RRI_REQ_SIZE);
if (!rri_req)
return -ENOMEM;

@@ -1412,7 +1423,7 @@ static int sas_configure_set(struct domain_device *dev, int phy_id,
u8 *cri_req;
u8 *cri_resp;

- cri_req = alloc_smp_req(CRI_REQ_SIZE);
+ cri_req = sas_alloc_smp_req(dev, CRI_REQ_SIZE);
if (!cri_req)
return -ENOMEM;

@@ -1627,7 +1638,7 @@ static int sas_get_phy_discover(struct domain_device *dev,
int res;
u8 *disc_req;

- disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
+ disc_req = sas_alloc_smp_req(dev, DISCOVER_REQ_SIZE);
if (!disc_req)
return -ENOMEM;

@@ -1723,7 +1734,7 @@ static int sas_get_ex_change_count(struct domain_device *dev, int *ecc)
u8 *rg_req;
struct smp_rg_resp *rg_resp;

- rg_req = alloc_smp_req(RG_REQ_SIZE);
+ rg_req = sas_alloc_smp_req(dev, RG_REQ_SIZE);
if (!rg_req)
return -ENOMEM;

diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index f5257103fdb6..2e6e5f6e50db 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -670,6 +670,9 @@ struct sas_domain_function_template {
/* GPIO support */
int (*lldd_write_gpio)(struct sas_ha_struct *, u8 reg_type,
u8 reg_index, u8 reg_count, u8 *write_data);
+
+ /* Allocation for SMP request */
+ void *(*lldd_alloc_smp_req)(int size);
};

extern int sas_register_ha(struct sas_ha_struct *);
--
2.33.0



2024-03-25 16:25:45

by Jason Yan

[permalink] [raw]
Subject: Re: [PATCH] scsi: libsas: Add SMP request allocation handler callback

On 2024/3/25 22:03, Damien Le Moal wrote:
> On 3/25/24 22:17, Yihang Li wrote:
>> This series [1] reducing the kmalloc() minimum alignment on arm64 to 8
>> (from 128).
>
> And ? What is the point you are trying to convey here ?
>
>> The hisi_sas has special requirements on the memory address alignment
>> (must be 16-byte-aligned) of the command request frame, so add a SMP
>> request allocation callback and fill it in for the hisi_sas driver.
>
> 128 is aligned to 16. So what is the problem you are trying to solve here ?
> Can you clarify ? I suspect this is all about memory allocation optimization ?

After series [1] been merged, kmalloc is 8-byte-aligned, however
hisi_sas hardware needs 16-byte-aligned. That's the problem.

>
>>
>> Link: https://lkml.kernel.org/r/[email protected] [1]
>> Signed-off-by: Yihang Li <[email protected]>
>> ---
>> drivers/scsi/hisi_sas/hisi_sas_main.c | 14 ++++++++++++
>> drivers/scsi/libsas/sas_expander.c | 31 ++++++++++++++++++---------
>> include/scsi/libsas.h | 3 +++
>> 3 files changed, 38 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
>> index 097dfe4b620d..40329558d435 100644
>> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
>> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
>> @@ -2031,6 +2031,19 @@ static int hisi_sas_write_gpio(struct sas_ha_struct *sha, u8 reg_type,
>> reg_index, reg_count, write_data);
>> }
>>
>> +static void *hisi_sas_alloc_smp_req(int size)
>> +{
>> + u8 *p;
>> +
>> + /* The address must be 16-byte-aligned. */
>
> ARCH_DMA_MINALIGN is not always 16, right ?
>
>> + size = ALIGN(size, ARCH_DMA_MINALIGN);
>> + p = kzalloc(size, GFP_KERNEL);
>> + if (p)
>> + p[0] = SMP_REQUEST;
>> +
>> + return p;
>> +}
>> +
>> static void hisi_sas_phy_disconnected(struct hisi_sas_phy *phy)
>> {
>> struct asd_sas_phy *sas_phy = &phy->sas_phy;
>> @@ -2130,6 +2143,7 @@ static struct sas_domain_function_template hisi_sas_transport_ops = {
>> .lldd_write_gpio = hisi_sas_write_gpio,
>> .lldd_tmf_aborted = hisi_sas_tmf_aborted,
>> .lldd_abort_timeout = hisi_sas_internal_abort_timeout,
>> + .lldd_alloc_smp_req = hisi_sas_alloc_smp_req,
>
> Why this complexity ? Why not simply modify alloc_smp_req() to have the required
> alignment ? This will avoid a costly indirect function call.

Yeah, I think it's simpler to modify alloc_smp_req() directly too.
Yihang, Can you please cook a new one?

Thansk,
Jason

2024-03-25 16:39:18

by Damien Le Moal

[permalink] [raw]
Subject: Re: [PATCH] scsi: libsas: Add SMP request allocation handler callback

On 3/25/24 22:17, Yihang Li wrote:
> This series [1] reducing the kmalloc() minimum alignment on arm64 to 8
> (from 128).

And ? What is the point you are trying to convey here ?

> The hisi_sas has special requirements on the memory address alignment
> (must be 16-byte-aligned) of the command request frame, so add a SMP
> request allocation callback and fill it in for the hisi_sas driver.

128 is aligned to 16. So what is the problem you are trying to solve here ?
Can you clarify ? I suspect this is all about memory allocation optimization ?

>
> Link: https://lkml.kernel.org/r/[email protected] [1]
> Signed-off-by: Yihang Li <[email protected]>
> ---
> drivers/scsi/hisi_sas/hisi_sas_main.c | 14 ++++++++++++
> drivers/scsi/libsas/sas_expander.c | 31 ++++++++++++++++++---------
> include/scsi/libsas.h | 3 +++
> 3 files changed, 38 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
> index 097dfe4b620d..40329558d435 100644
> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
> @@ -2031,6 +2031,19 @@ static int hisi_sas_write_gpio(struct sas_ha_struct *sha, u8 reg_type,
> reg_index, reg_count, write_data);
> }
>
> +static void *hisi_sas_alloc_smp_req(int size)
> +{
> + u8 *p;
> +
> + /* The address must be 16-byte-aligned. */

ARCH_DMA_MINALIGN is not always 16, right ?

> + size = ALIGN(size, ARCH_DMA_MINALIGN);
> + p = kzalloc(size, GFP_KERNEL);
> + if (p)
> + p[0] = SMP_REQUEST;
> +
> + return p;
> +}
> +
> static void hisi_sas_phy_disconnected(struct hisi_sas_phy *phy)
> {
> struct asd_sas_phy *sas_phy = &phy->sas_phy;
> @@ -2130,6 +2143,7 @@ static struct sas_domain_function_template hisi_sas_transport_ops = {
> .lldd_write_gpio = hisi_sas_write_gpio,
> .lldd_tmf_aborted = hisi_sas_tmf_aborted,
> .lldd_abort_timeout = hisi_sas_internal_abort_timeout,
> + .lldd_alloc_smp_req = hisi_sas_alloc_smp_req,

Why this complexity ? Why not simply modify alloc_smp_req() to have the required
alignment ? This will avoid a costly indirect function call.

> };
>
> void hisi_sas_init_mem(struct hisi_hba *hisi_hba)
> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
> index a2204674b680..0fd0507f7fc6 100644
> --- a/drivers/scsi/libsas/sas_expander.c
> +++ b/drivers/scsi/libsas/sas_expander.c
> @@ -141,6 +141,17 @@ static inline void *alloc_smp_req(int size)
> return p;
> }
>
> +static void *sas_alloc_smp_req(struct domain_device *dev, int size)
> +{
> + struct sas_internal *i =
> + to_sas_internal(dev->port->ha->shost->transportt);
> +
> + if (i->dft->lldd_alloc_smp_req)
> + return i->dft->lldd_alloc_smp_req(size);
> +
> + return alloc_smp_req(size);
> +}
> +
> static inline void *alloc_smp_resp(int size)
> {
> return kzalloc(size, GFP_KERNEL);
> @@ -377,7 +388,7 @@ int sas_ex_phy_discover(struct domain_device *dev, int single)
> u8 *disc_req;
> struct smp_disc_resp *disc_resp;
>
> - disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
> + disc_req = sas_alloc_smp_req(dev, DISCOVER_REQ_SIZE);
> if (!disc_req)
> return -ENOMEM;
>
> @@ -440,7 +451,7 @@ static int sas_ex_general(struct domain_device *dev)
> int res;
> int i;
>
> - rg_req = alloc_smp_req(RG_REQ_SIZE);
> + rg_req = sas_alloc_smp_req(dev, RG_REQ_SIZE);
> if (!rg_req)
> return -ENOMEM;
>
> @@ -519,7 +530,7 @@ static int sas_ex_manuf_info(struct domain_device *dev)
> u8 *mi_resp;
> int res;
>
> - mi_req = alloc_smp_req(MI_REQ_SIZE);
> + mi_req = sas_alloc_smp_req(dev, MI_REQ_SIZE);
> if (!mi_req)
> return -ENOMEM;
>
> @@ -560,7 +571,7 @@ int sas_smp_phy_control(struct domain_device *dev, int phy_id,
> u8 *pc_resp;
> int res;
>
> - pc_req = alloc_smp_req(PC_REQ_SIZE);
> + pc_req = sas_alloc_smp_req(dev, PC_REQ_SIZE);
> if (!pc_req)
> return -ENOMEM;
>
> @@ -642,7 +653,7 @@ int sas_smp_get_phy_events(struct sas_phy *phy)
> struct sas_rphy *rphy = dev_to_rphy(phy->dev.parent);
> struct domain_device *dev = sas_find_dev_by_rphy(rphy);
>
> - req = alloc_smp_req(RPEL_REQ_SIZE);
> + req = sas_alloc_smp_req(dev, RPEL_REQ_SIZE);
> if (!req)
> return -ENOMEM;
>
> @@ -682,7 +693,7 @@ int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
> struct smp_rps_resp *rps_resp)
> {
> int res;
> - u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE);
> + u8 *rps_req = sas_alloc_smp_req(dev, RPS_REQ_SIZE);
> u8 *resp = (u8 *)rps_resp;
>
> if (!rps_req)
> @@ -1344,7 +1355,7 @@ static int sas_configure_present(struct domain_device *dev, int phy_id,
> *present = 0;
> *index = 0;
>
> - rri_req = alloc_smp_req(RRI_REQ_SIZE);
> + rri_req = sas_alloc_smp_req(dev, RRI_REQ_SIZE);
> if (!rri_req)
> return -ENOMEM;
>
> @@ -1412,7 +1423,7 @@ static int sas_configure_set(struct domain_device *dev, int phy_id,
> u8 *cri_req;
> u8 *cri_resp;
>
> - cri_req = alloc_smp_req(CRI_REQ_SIZE);
> + cri_req = sas_alloc_smp_req(dev, CRI_REQ_SIZE);
> if (!cri_req)
> return -ENOMEM;
>
> @@ -1627,7 +1638,7 @@ static int sas_get_phy_discover(struct domain_device *dev,
> int res;
> u8 *disc_req;
>
> - disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
> + disc_req = sas_alloc_smp_req(dev, DISCOVER_REQ_SIZE);
> if (!disc_req)
> return -ENOMEM;
>
> @@ -1723,7 +1734,7 @@ static int sas_get_ex_change_count(struct domain_device *dev, int *ecc)
> u8 *rg_req;
> struct smp_rg_resp *rg_resp;
>
> - rg_req = alloc_smp_req(RG_REQ_SIZE);
> + rg_req = sas_alloc_smp_req(dev, RG_REQ_SIZE);
> if (!rg_req)
> return -ENOMEM;
>
> diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
> index f5257103fdb6..2e6e5f6e50db 100644
> --- a/include/scsi/libsas.h
> +++ b/include/scsi/libsas.h
> @@ -670,6 +670,9 @@ struct sas_domain_function_template {
> /* GPIO support */
> int (*lldd_write_gpio)(struct sas_ha_struct *, u8 reg_type,
> u8 reg_index, u8 reg_count, u8 *write_data);
> +
> + /* Allocation for SMP request */
> + void *(*lldd_alloc_smp_req)(int size);
> };
>
> extern int sas_register_ha(struct sas_ha_struct *);

--
Damien Le Moal
Western Digital Research


2024-03-25 16:51:16

by John Garry

[permalink] [raw]
Subject: Re: [PATCH] scsi: libsas: Add SMP request allocation handler callback

On 25/03/2024 14:21, Jason Yan wrote:
> On 2024/3/25 22:03, Damien Le Moal wrote:
>> On 3/25/24 22:17, Yihang Li wrote:
>>> This series [1] reducing the kmalloc() minimum alignment on arm64 to 8
>>> (from 128).
>>
>> And ? What is the point you are trying to convey here ?
>>
>>> The hisi_sas has special requirements on the memory address alignment
>>> (must be 16-byte-aligned) of the command request frame, so add a SMP
>>> request allocation callback and fill it in for the hisi_sas driver.
>>
>> 128 is aligned to 16. So what is the problem you are trying to solve
>> here ?
>> Can you clarify ? I suspect this is all about memory allocation
>> optimization ?
>
> After series [1] been merged, kmalloc is 8-byte-aligned, however
> hisi_sas hardware needs 16-byte-aligned. That's the problem.
>
>>
>>>
>>> Link:
>>> https://urldefense.com/v3/__https://lkml.kernel.org/r/[email protected]__;!!ACWV5N9M2RV99hQ!L85qzmByNbkBbZByXKuNMAhvt8wxKPCsogKt3Pgn93DTkzfc54jA3of5XL8oEDDDDTMU1OtghdKiLZdKe5ub$  [1]
>>> Signed-off-by: Yihang Li <[email protected]>
>>> ---
>>>   drivers/scsi/hisi_sas/hisi_sas_main.c | 14 ++++++++++++
>>>   drivers/scsi/libsas/sas_expander.c    | 31 ++++++++++++++++++---------
>>>   include/scsi/libsas.h                 |  3 +++
>>>   3 files changed, 38 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> b/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> index 097dfe4b620d..40329558d435 100644
>>> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> @@ -2031,6 +2031,19 @@ static int hisi_sas_write_gpio(struct
>>> sas_ha_struct *sha, u8 reg_type,
>>>                   reg_index, reg_count, write_data);
>>>   }
>>> +static void *hisi_sas_alloc_smp_req(int size)
>>> +{
>>> +    u8 *p;
>>> +
>>> +    /* The address must be 16-byte-aligned. */
>>
>> ARCH_DMA_MINALIGN is not always 16, right ?
>>
>>> +    size = ALIGN(size, ARCH_DMA_MINALIGN);
>>> +    p = kzalloc(size, GFP_KERNEL);

Please make it clear that kmalloc() will return a naturally-aligned
memory for power-of-2 sizes, and so ensuring that size is roundup to 16B
will give a data which is aligned to 16B

>>> +    if (p)
>>> +        p[0] = SMP_REQUEST;
>>> +
>>> +    return p;
>>> +}
>>> +
>>>   static void hisi_sas_phy_disconnected(struct hisi_sas_phy *phy)
>>>   {
>>>       struct asd_sas_phy *sas_phy = &phy->sas_phy;
>>> @@ -2130,6 +2143,7 @@ static struct sas_domain_function_template
>>> hisi_sas_transport_ops = {
>>>       .lldd_write_gpio    = hisi_sas_write_gpio,
>>>       .lldd_tmf_aborted    = hisi_sas_tmf_aborted,
>>>       .lldd_abort_timeout    = hisi_sas_internal_abort_timeout,
>>> +    .lldd_alloc_smp_req    = hisi_sas_alloc_smp_req,
>>
>> Why this complexity ? Why not simply modify alloc_smp_req() to have
>> the required
>> alignment ? This will avoid a costly indirect function call.
>
> Yeah, I think it's simpler to modify alloc_smp_req() directly too.
> Yihang, Can you please cook a new one?
>
> Thansk,
> Jason


2024-03-26 06:35:04

by Yihang Li

[permalink] [raw]
Subject: Re: [PATCH] scsi: libsas: Add SMP request allocation handler callback



On 2024/3/25 22:21, Jason Yan wrote:
> On 2024/3/25 22:03, Damien Le Moal wrote:
>> On 3/25/24 22:17, Yihang Li wrote:
>>> This series [1] reducing the kmalloc() minimum alignment on arm64 to 8
>>> (from 128).
>>
>> And ? What is the point you are trying to convey here ?
>>
>>> The hisi_sas has special requirements on the memory address alignment
>>> (must be 16-byte-aligned) of the command request frame, so add a SMP
>>> request allocation callback and fill it in for the hisi_sas driver.
>>
>> 128 is aligned to 16. So what is the problem you are trying to solve here ?
>> Can you clarify ? I suspect this is all about memory allocation optimization ?
>
> After series [1] been merged, kmalloc is 8-byte-aligned, however hisi_sas hardware needs 16-byte-aligned. That's the problem.

Yes, that's the problem. I will explain it in detail in the next version.

>
>>
>>>
>>> Link: https://lkml.kernel.org/r/[email protected] [1]
>>> Signed-off-by: Yihang Li <[email protected]>
>>> ---
>>> drivers/scsi/hisi_sas/hisi_sas_main.c | 14 ++++++++++++
>>> drivers/scsi/libsas/sas_expander.c | 31 ++++++++++++++++++---------
>>> include/scsi/libsas.h | 3 +++
>>> 3 files changed, 38 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> index 097dfe4b620d..40329558d435 100644
>>> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
>>> @@ -2031,6 +2031,19 @@ static int hisi_sas_write_gpio(struct sas_ha_struct *sha, u8 reg_type,
>>> reg_index, reg_count, write_data);
>>> }
>>> +static void *hisi_sas_alloc_smp_req(int size)
>>> +{
>>> + u8 *p;
>>> +
>>> + /* The address must be 16-byte-aligned. */
>>
>> ARCH_DMA_MINALIGN is not always 16, right ?
>>
>>> + size = ALIGN(size, ARCH_DMA_MINALIGN);
>>> + p = kzalloc(size, GFP_KERNEL);
>>> + if (p)
>>> + p[0] = SMP_REQUEST;
>>> +
>>> + return p;
>>> +}
>>> +
>>> static void hisi_sas_phy_disconnected(struct hisi_sas_phy *phy)
>>> {
>>> struct asd_sas_phy *sas_phy = &phy->sas_phy;
>>> @@ -2130,6 +2143,7 @@ static struct sas_domain_function_template hisi_sas_transport_ops = {
>>> .lldd_write_gpio = hisi_sas_write_gpio,
>>> .lldd_tmf_aborted = hisi_sas_tmf_aborted,
>>> .lldd_abort_timeout = hisi_sas_internal_abort_timeout,
>>> + .lldd_alloc_smp_req = hisi_sas_alloc_smp_req,
>>
>> Why this complexity ? Why not simply modify alloc_smp_req() to have the required
>> alignment ? This will avoid a costly indirect function call.
>
> Yeah, I think it's simpler to modify alloc_smp_req() directly too. Yihang, Can you please cook a new one?

Sure, I will post a new version later.
The reason why I did not directly modify alloc_smp_req() is that I think the requirement that the command frame must be 16-byte aligned is hisi_sas private and not a general requirement.
To avoid the impact on other drivers, I only add aligned to 16B in hisi_sas. If this measure is considered pointless, I will directly modify alloc_smp_req().

Thanks,
Yihang

>
> Thansk,
> Jason
> .
>