On Sun, 05 Feb 2023 17:02:56 -0800
Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> Expand the region creation infrastructure to enable 'ram'
> (volatile-memory) regions. The internals of create_pmem_region_store()
> and create_pmem_region_show() are factored out into helpers
> __create_region() and __create_region_show() for the 'ram' case to
> reuse.
>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Entirely trivial comments inline.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-bus-cxl | 22 +++++-----
> drivers/cxl/core/core.h | 1
> drivers/cxl/core/port.c | 14 ++++++
> drivers/cxl/core/region.c | 71 +++++++++++++++++++++++++------
> 4 files changed, 82 insertions(+), 26 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
> index 4c4e1cbb1169..3acf2f17a73f 100644
> --- a/Documentation/ABI/testing/sysfs-bus-cxl
> +++ b/Documentation/ABI/testing/sysfs-bus-cxl
> @@ -285,20 +285,20 @@ Description:
> interleave_granularity).
>
>
> -What: /sys/bus/cxl/devices/decoderX.Y/create_pmem_region
> -Date: May, 2022
> -KernelVersion: v6.0
> +What: /sys/bus/cxl/devices/decoderX.Y/create_{pmem,ram}_region
> +Date: May, 2022, January, 2023
> +KernelVersion: v6.0 (pmem), v6.3 (ram)
> Contact: linux-cxl@xxxxxxxxxxxxxxx
> Description:
> (RW) Write a string in the form 'regionZ' to start the process
> - of defining a new persistent memory region (interleave-set)
> - within the decode range bounded by root decoder 'decoderX.Y'.
> - The value written must match the current value returned from
> - reading this attribute. An atomic compare exchange operation is
> - done on write to assign the requested id to a region and
> - allocate the region-id for the next creation attempt. EBUSY is
> - returned if the region name written does not match the current
> - cached value.
> + of defining a new persistent, or volatile memory region
> + (interleave-set) within the decode range bounded by root decoder
> + 'decoderX.Y'. The value written must match the current value
> + returned from reading this attribute. An atomic compare exchange
> + operation is done on write to assign the requested id to a
> + region and allocate the region-id for the next creation attempt.
> + EBUSY is returned if the region name written does not match the
> + current cached value.
>
>
> What: /sys/bus/cxl/devices/decoderX.Y/delete_region
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 8c04672dca56..5eb873da5a30 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -11,6 +11,7 @@ extern struct attribute_group cxl_base_attribute_group;
>
> #ifdef CONFIG_CXL_REGION
> extern struct device_attribute dev_attr_create_pmem_region;
> +extern struct device_attribute dev_attr_create_ram_region;
> extern struct device_attribute dev_attr_delete_region;
> extern struct device_attribute dev_attr_region;
> extern const struct device_type cxl_pmem_region_type;
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 8566451cb22f..47e450c3a5a9 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -294,6 +294,7 @@ static struct attribute *cxl_decoder_root_attrs[] = {
> &dev_attr_cap_type3.attr,
> &dev_attr_target_list.attr,
> SET_CXL_REGION_ATTR(create_pmem_region)
> + SET_CXL_REGION_ATTR(create_ram_region)
> SET_CXL_REGION_ATTR(delete_region)
> NULL,
> };
> @@ -305,6 +306,13 @@ static bool can_create_pmem(struct cxl_root_decoder *cxlrd)
> return (cxlrd->cxlsd.cxld.flags & flags) == flags;
> }
>
> +static bool can_create_ram(struct cxl_root_decoder *cxlrd)
> +{
> + unsigned long flags = CXL_DECODER_F_TYPE3 | CXL_DECODER_F_RAM;
> +
> + return (cxlrd->cxlsd.cxld.flags & flags) == flags;
> +}
> +
> static umode_t cxl_root_decoder_visible(struct kobject *kobj, struct attribute *a, int n)
> {
> struct device *dev = kobj_to_dev(kobj);
> @@ -313,7 +321,11 @@ static umode_t cxl_root_decoder_visible(struct kobject *kobj, struct attribute *
> if (a == CXL_REGION_ATTR(create_pmem_region) && !can_create_pmem(cxlrd))
> return 0;
>
> - if (a == CXL_REGION_ATTR(delete_region) && !can_create_pmem(cxlrd))
> + if (a == CXL_REGION_ATTR(create_ram_region) && !can_create_ram(cxlrd))
> + return 0;
> +
> + if (a == CXL_REGION_ATTR(delete_region) &&
> + !(can_create_pmem(cxlrd) || can_create_ram(cxlrd)))
> return 0;
>
> return a->mode;
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 53d6dbe4de6d..8dea49c021b8 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1685,6 +1685,15 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
> struct device *dev;
> int rc;
>
> + switch (mode) {
> + case CXL_DECODER_RAM:
> + case CXL_DECODER_PMEM:
> + break;
> + default:
> + dev_err(&cxlrd->cxlsd.cxld.dev, "unsupported mode %d\n", mode);
> + return ERR_PTR(-EINVAL);
> + }
> +
> cxlr = cxl_region_alloc(cxlrd, id);
> if (IS_ERR(cxlr))
> return cxlr;
> @@ -1713,12 +1722,38 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
> return ERR_PTR(rc);
> }
>
> +static ssize_t __create_region_show(struct cxl_root_decoder *cxlrd, char *buf)
> +{
> + return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
> +}
> +
> static ssize_t create_pmem_region_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
> + return __create_region_show(to_cxl_root_decoder(dev), buf);
> +}
>
> - return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
> +static ssize_t create_ram_region_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return __create_region_show(to_cxl_root_decoder(dev), buf);
> +}
> +
> +static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd,
> + enum cxl_decoder_mode mode, int id)
> +{
> + int rc;
> +
> + rc = memregion_alloc(GFP_KERNEL);
> + if (rc < 0)
> + return ERR_PTR(rc);
> +
> + if (atomic_cmpxchg(&cxlrd->region_id, id, rc) != id) {
> + memregion_free(rc);
> + return ERR_PTR(-EBUSY);
> + }
> +
> + return devm_cxl_add_region(cxlrd, id, mode, CXL_DECODER_EXPANDER);
> }
>
> static ssize_t create_pmem_region_store(struct device *dev,
> @@ -1727,29 +1762,37 @@ static ssize_t create_pmem_region_store(struct device *dev,
> {
> struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
> struct cxl_region *cxlr;
> - int id, rc;
> + int rc, id;
>
> rc = sscanf(buf, "region%d\n", &id);
> if (rc != 1)
> return -EINVAL;
>
> - rc = memregion_alloc(GFP_KERNEL);
> - if (rc < 0)
> - return rc;
> + cxlr = __create_region(cxlrd, CXL_DECODER_PMEM, id);
> + if (IS_ERR(cxlr))
> + return PTR_ERR(cxlr);
I'd have a blank line here - see below.
> + return len;
> +}
> +DEVICE_ATTR_RW(create_pmem_region);
>
> - if (atomic_cmpxchg(&cxlrd->region_id, id, rc) != id) {
> - memregion_free(rc);
> - return -EBUSY;
> - }
> +static ssize_t create_ram_region_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
> + struct cxl_region *cxlr;
> + int rc, id;
>
> - cxlr = devm_cxl_add_region(cxlrd, id, CXL_DECODER_PMEM,
> - CXL_DECODER_EXPANDER);
> + rc = sscanf(buf, "region%d\n", &id);
> + if (rc != 1)
> + return -EINVAL;
> +
> + cxlr = __create_region(cxlrd, CXL_DECODER_RAM, id);
> if (IS_ERR(cxlr))
> return PTR_ERR(cxlr);
> -
Just so you know I read to the end!
Spurious unrelated white space change :)
> return len;
> }
> -DEVICE_ATTR_RW(create_pmem_region);
> +DEVICE_ATTR_RW(create_ram_region);
>
> static ssize_t region_show(struct device *dev, struct device_attribute *attr,
> char *buf)
>
