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

Alejandro Lucero Palau
2024-09-16T12:39:42Z

On 9/12/24 19:19, Dave Jiang wrote:
>
> 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

I think you are right. It was a quick fix for having things working and
not thought about it in detail.

I'll do and fix it for v4.

Thanks!

>> +
>> 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