Re: [PATCH v3 09/20] cxl: support type2 memdev creation

Dave Jiang
2024-09-12T18:19:27Z

On 9/7/24 1:18 AM, alejandro.lucero-palau@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
>
> Add memdev creation from sfc driver.
>
> Current cxl core is relying on a CXL_DEVTYPE_CLASSMEM type device when
> creating a memdev leading to problems when obtaining cxl_memdev_state
> references from a CXL_DEVTYPE_DEVMEM type. This last device type is
> managed by a specific vendor driver and does not need same sysfs files
> since not userspace intervention is expected. This patch checks for the
> right device type in those functions using cxl_memdev_state.
>
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
> drivers/cxl/core/cdat.c | 3 +++
> drivers/cxl/core/memdev.c | 9 +++++++++
> drivers/cxl/mem.c | 17 +++++++++++------
> drivers/net/ethernet/sfc/efx_cxl.c | 7 +++++++
> include/linux/cxl/cxl.h | 2 ++
> 5 files changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
> index bb83867d9fec..0d4679c137d4 100644
> --- a/drivers/cxl/core/cdat.c
> +++ b/drivers/cxl/core/cdat.c
> @@ -558,6 +558,9 @@ void cxl_region_perf_data_calculate(struct cxl_region *cxlr,
> };
> struct cxl_dpa_perf *perf;
>
> + if (!mds)
> + return;
> +
> switch (cxlr->mode) {
> case CXL_DECODER_RAM:
> perf = &mds->ram_perf;
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 836faf09b328..5f8418620b70 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -468,6 +468,9 @@ static umode_t cxl_ram_visible(struct kobject *kobj, struct attribute *a, int n)
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> + if (!mds)
> + return 0;

I think instead of altering the sysfs visible attributes, what you really want is to not register the unwanted group attributes. Or basically only register the cxl_memdev_attribute_group and not the other ones. Otherwise it gets really messy. And whomever adds future attributes need to also remember the special case. I think you can refer to core/port.c and look at the different decoder types as inspiration for creating different memdev types where it has cxl_decoder_base_attribute_group and then tack on specific attribute groups.

DJ

> +
> if (a == &dev_attr_ram_qos_class.attr)
> if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
> return 0;
> @@ -487,6 +490,9 @@ static umode_t cxl_pmem_visible(struct kobject *kobj, struct attribute *a, int n
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> + if (!mds)
> + return 0;
> +
> if (a == &dev_attr_pmem_qos_class.attr)
> if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
> return 0;
> @@ -507,6 +513,9 @@ static umode_t cxl_memdev_security_visible(struct kobject *kobj,
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> + if (!mds)
> + return 0;
> +
> if (a == &dev_attr_security_sanitize.attr &&
> !test_bit(CXL_SEC_ENABLED_SANITIZE, mds->security.enabled_cmds))
> return 0;
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 7de232eaeb17..5c7ad230bccb 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -131,12 +131,14 @@ static int cxl_mem_probe(struct device *dev)
> dentry = cxl_debugfs_create_dir(dev_name(dev));
> debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
>
> - if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
> - debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
> - &cxl_poison_inject_fops);
> - if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
> - debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
> - &cxl_poison_clear_fops);
> + if (mds) {
> + if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
> + debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
> + &cxl_poison_inject_fops);
> + if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
> + debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
> + &cxl_poison_clear_fops);
> + }
>
> rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
> if (rc)
> @@ -222,6 +224,9 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> + if (!mds)
> + return 0;
> +
> if (a == &dev_attr_trigger_poison_list.attr)
> if (!test_bit(CXL_POISON_ENABLED_LIST,
> mds->poison.enabled_cmds))
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index 14fab41fe10a..899bc823a212 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -83,6 +83,13 @@ int efx_cxl_init(struct efx_nic *efx)
> */
> cxl_set_media_ready(cxl->cxlds);
>
> + cxl->cxlmd = devm_cxl_add_memdev(&pci_dev->dev, cxl->cxlds);
> + if (IS_ERR(cxl->cxlmd)) {
> + pci_err(pci_dev, "CXL accel memdev creation failed");
> + rc = PTR_ERR(cxl->cxlmd);
> + goto err;
> + }
> +
> return 0;
> err:
> kfree(cxl->cxlds);
> diff --git a/include/linux/cxl/cxl.h b/include/linux/cxl/cxl.h
> index 08723b2d75bc..fc0859f841dc 100644
> --- a/include/linux/cxl/cxl.h
> +++ b/include/linux/cxl/cxl.h
> @@ -55,4 +55,6 @@ int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds);
> int cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
> int cxl_release_resource(struct cxl_dev_state *cxlds, enum cxl_resource type);
> void cxl_set_media_ready(struct cxl_dev_state *cxlds);
> +struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
> + struct cxl_dev_state *cxlds);
> #endif