On 23/06/25 10:43AM, Jonathan Cameron wrote:
On Tue, 17 Jun 2025 18:09:38 +0530
Neeraj Kumar <s.nee...@samsung.com> wrote:
Added exported cxl_create_pmem_region routine to create cxl pmem region
For function names always add () after and drop 'function/routine' etc.
Ends up shorter and easier to read.
Sure, Will fix it accordingly
from LSA parsed cxl region information.
Inspirition for the function is taken from ndctl device attribute
(_store) call. It allocates cxlr and fills information parsed from LSA
and calls device_add(&cxlr->dev) to initiates further region creation
porbes
Spell check.
Thanks, Will fix it up.
Signed-off-by: Neeraj Kumar <s.nee...@samsung.com>
---
drivers/cxl/core/port.c | 6 ++
drivers/cxl/core/region.c | 208 ++++++++++++++++++++++++++++++++++++++
drivers/cxl/cxl.h | 11 ++
3 files changed, 225 insertions(+)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index b98b1ccffd1c..8990e3c3474d 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2522,6 +2522,214 @@ static ssize_t create_ram_region_show(struct device
*dev,
return __create_region_show(to_cxl_root_decoder(dev), buf);
}
+static ssize_t update_region_size(struct cxl_region *cxlr, u64 val)
+{
+ int rc;
+
+ rc = down_write_killable(&cxl_region_rwsem);
ACQUIRE() as mentioned below.
Sure, Let me look at Dan's new ACQUIRE() series. I will update it in V1
+ if (rc)
+ return rc;
+
+ if (val)
+ rc = alloc_hpa(cxlr, val);
+ else
+ rc = free_hpa(cxlr);
+ up_write(&cxl_region_rwsem);
+
+ if (rc)
+ return rc;
return rc;
Thanks, I will update it.
+
+ return 0;
+}
+
+static ssize_t update_region_dpa_size(struct cxl_region *cxlr,
+ struct cxl_decoder *cxld,
+ unsigned long long size)
+{
+ int rc;
+ struct cxl_endpoint_decoder *cxled =
+ to_cxl_endpoint_decoder(&cxld->dev);
+
+ if (!IS_ALIGNED(size, SZ_256M))
+ return -EINVAL;
+
+ rc = cxl_dpa_free(cxled);
+ if (rc)
+ return rc;
+
+ if (size == 0)
+ return 0;
+
+ rc = cxl_dpa_alloc(cxled, size);
return cxl_dpa_alloc()
Unless something more is getting added here in later patches in which case
you can ignore this comment.
Thanks, Will fix it accordingly
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+static ssize_t update_region_dpa_mode(struct cxl_region *cxlr,
+ struct cxl_decoder *cxld)
+{
+ int rc;
+ struct cxl_endpoint_decoder *cxled =
+ to_cxl_endpoint_decoder(&cxld->dev);
Maybe don't bother with local variable and just put this
below as the parameter.
Sure, I will fix it.
+
+ rc = cxl_dpa_set_mode(cxled, CXL_DECODER_PMEM);
return cxl_dpa_set_mode()
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+static size_t attach_region_target(struct cxl_region *cxlr,
+ struct cxl_decoder *cxld, int pos)
+{
+ int rc;
+ struct cxl_endpoint_decoder *cxled =
+ to_cxl_endpoint_decoder(&cxld->dev);
+
+ rc = attach_target(cxlr, cxled, pos, TASK_INTERRUPTIBLE);
+
No blank line here
Sure, I will fix it.
+ if (rc < 0)
Can it ever be > 0 ?
If not, return attach_target() should be fine.
Yes we can directly return from here, will fix it in V1
+ return rc;
+
+ return 0;
+}
+
+static ssize_t commit_region(struct cxl_region *cxlr)
+{
+ struct cxl_region_params *p = &cxlr->params;
+ ssize_t rc;
+
+ rc = down_write_killable(&cxl_region_rwsem);
Maybe look at Dan's new ACQUIRE() series. The last patch in there
is targeting code similar to this.
Sure, Let me look at Dan's new ACQUIRE() series. I will update it in V1
+ if (rc)
+ return rc;
+
+ /* Already in the requested state? */
+ if (p->state >= CXL_CONFIG_COMMIT)
+ goto out;
+
+ /* Not ready to commit? */
+ if (p->state < CXL_CONFIG_ACTIVE) {
+ rc = -ENXIO;
+ goto out;
+ }
+
+ /*
+ * Invalidate caches before region setup to drop any speculative
+ * consumption of this address space
+ */
+ rc = cxl_region_invalidate_memregion(cxlr);
+ if (rc)
+ goto out;
+
+ rc = cxl_region_decode_commit(cxlr);
+ if (rc == 0)
With AQUIRE() stuff you can just do
if (rc)
return rc;
here
Thanks, Will update it accordingly.
+ p->state = CXL_CONFIG_COMMIT;
+out:
+ up_write(&cxl_region_rwsem);
+ if (rc)
+ return rc;
+ return 0;
+}
+
+static struct cxl_region *
+devm_cxl_pmem_add_region(struct cxl_root_decoder *cxlrd,
+ struct cxl_decoder *cxld,
+ struct cxl_pmem_region_params *params, int id,
+ enum cxl_decoder_mode mode, enum cxl_decoder_type type)
+{
+ struct cxl_port *port;
+ struct cxl_region *cxlr;
+ struct cxl_region_params *p;
+ struct device *dev;
+ int rc;
+
+ if (!cxlrd)
+ return ERR_PTR(-EINVAL);
For a check like this, add a comment on why it might be NULL.
If it can't be, then drop the check.
Sure, I will fix it in V1
+
+ port = to_cxl_port(cxlrd->cxlsd.cxld.dev.parent);
Maybe add a comment on which port this actually is. These long indirections
can make that hard to figure out!
Sure, I will fix it in V1
+
+ cxlr = cxl_region_alloc(cxlrd, id);
+ if (IS_ERR(cxlr))
+ return cxlr;
+ cxlr->mode = mode;
+ cxlr->type = type;
+
+ dev = &cxlr->dev;
+ rc = dev_set_name(dev, "region%d", id);
+ if (rc)
+ goto err;
+
+ p = &cxlr->params;
+ p->uuid = params->uuid;
+ p->interleave_ways = params->nlabel;
+ p->interleave_granularity = params->ig;
+
+ /* Update region size */
+ if (update_region_size(cxlr, params->rawsize))
+ goto err;
+
+ /* Flush cxl wq */
Much more useful to say 'why' you are flushing it. It's obvious
from the code that you are.
Sure Will update the comment properly
+ cxl_wq_flush();
+
+ /* Clear DPA Size */
I'd look at all these comments and where they are obvious, drop the comment
and let the code speak for itself.
Sure, Will update accordingly
+ if (update_region_dpa_size(cxlr, cxld, 0))
+ goto err;
+
+ /* Update DPA mode */
+ if (update_region_dpa_mode(cxlr, cxld))
+ goto err;
+
+ /* Update DPA Size */
+ if (update_region_dpa_size(cxlr, cxld, params->rawsize))
+ goto err;
+
+ /* Attach region targets */
It's attaching just one by the look of it. I'd just drop the comment.
Sure, Will update accordingly
+ if (attach_region_target(cxlr, cxld, params->position))
+ goto err;
+
+ /* Commit Region */
+ if (commit_region(cxlr))
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ rc = devm_add_action_or_reset(port->uport_dev, unregister_region, cxlr);
+ if (rc)
+ return ERR_PTR(rc);
+
+ dev_dbg(port->uport_dev, "%s: created %s\n",
+ dev_name(&cxlrd->cxlsd.cxld.dev), dev_name(dev));
+ return cxlr;
+
+err:
+ put_device(dev);
+ return ERR_PTR(rc);
+}
+
+struct cxl_region *cxl_create_pmem_region(struct cxl_root_decoder *cxlrd,
+ struct cxl_decoder *cxld,
+ struct cxl_pmem_region_params *params, 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);
+ }
I'm a little surprised not to see cleanup of the memregion via
devm somewhere here.
Actually its cleanup is happening at cxl_region_release().
During cxl_region_alloc, cxlr is allocated whose dev->type is
cxl_region_type
const struct device_type cxl_region_type = {
.name = "cxl_region",
.release = cxl_region_release,
.groups = region_groups
};
+
+ return devm_cxl_pmem_add_region(cxlrd, cxld, params, id,
+ CXL_DECODER_PMEM, CXL_DECODER_HOSTONLYMEM);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_create_pmem_region, "CXL");
+
static struct cxl_region *__create_region(struct cxl_root_decoder *cxlrd,
enum cxl_decoder_mode mode, int id)
{
