Re: [PATCH] scsi: libsas: Add SMP request allocation handler callback
From: Damien Le Moal
Date: Mon Mar 25 2024 - 12:13:25 EST
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/20230612153201.554742-1-catalin.marinas@xxxxxxx [1]
> Signed-off-by: Yihang Li <liyihang9@xxxxxxxxxx>
> ---
> 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