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cxl/port: Arrange for always synchronous endpoint attach

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Make it so that upon return from devm_cxl_add_endpoint() that
cxl_mem_probe() can assume that the endpoint has had a chance to complete
cxl_port_probe().  I.e. cxl_port module loading has completed prior to
device registration.

Delete the MODULE_SOFTDEP() as it is not sufficient for this purpose, but a
hard link-time dependency is reliable. Specifically MODULE_SOFTDEP() does
not guarantee that the module loading has completed prior to the completion
of the current module's init.

Cc: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Cc: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Alejandro Lucero <alucerop@amd.com>
Link: https://patch.msgid.link/20251216005616.3090129-4-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
This commit is contained in:
Dan Williams
2025-12-15 16:56:13 -08:00
committed by Dave Jiang
parent 1f1cb7f0c2
commit ae201a0092
3 changed files with 42 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/cxl/cxl.h
View File

@@ -780,6 +780,8 @@ struct cxl_port *devm_cxl_add_port(struct device *host,
struct cxl_dport *parent_dport);
struct cxl_root *devm_cxl_add_root(struct device *host,
const struct cxl_root_ops *ops);
int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
struct cxl_dport *parent_dport);
struct cxl_root *find_cxl_root(struct cxl_port *port);
DEFINE_FREE(put_cxl_root, struct cxl_root *, if (_T) put_device(&_T->port.dev))

43
drivers/cxl/mem.c
View File

@@ -45,44 +45,6 @@ static int cxl_mem_dpa_show(struct seq_file *file, void *data)
return 0;
}
static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
struct cxl_dport *parent_dport)
{
struct cxl_port *parent_port = parent_dport->port;
struct cxl_port *endpoint, *iter, *down;
int rc;
/*
* Now that the path to the root is established record all the
* intervening ports in the chain.
*/
for (iter = parent_port, down = NULL; !is_cxl_root(iter);
down = iter, iter = to_cxl_port(iter->dev.parent)) {
struct cxl_ep *ep;
ep = cxl_ep_load(iter, cxlmd);
ep->next = down;
}
/* Note: endpoint port component registers are derived from @cxlds */
endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE,
parent_dport);
if (IS_ERR(endpoint))
return PTR_ERR(endpoint);
rc = cxl_endpoint_autoremove(cxlmd, endpoint);
if (rc)
return rc;
if (!endpoint->dev.driver) {
dev_err(&cxlmd->dev, "%s failed probe\n",
dev_name(&endpoint->dev));
return -ENXIO;
}
return 0;
}
static int cxl_debugfs_poison_inject(void *data, u64 dpa)
{
struct cxl_memdev *cxlmd = data;
@@ -275,8 +237,3 @@ MODULE_DESCRIPTION("CXL: Memory Expansion");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("CXL");
MODULE_ALIAS_CXL(CXL_DEVICE_MEMORY_EXPANDER);
/*
* create_endpoint() wants to validate port driver attach immediately after
* endpoint registration.
*/
MODULE_SOFTDEP("pre: cxl_port");

40
drivers/cxl/port.c
View File

@@ -156,10 +156,50 @@ static struct cxl_driver cxl_port_driver = {
.probe = cxl_port_probe,
.id = CXL_DEVICE_PORT,
.drv = {
.probe_type = PROBE_FORCE_SYNCHRONOUS,
.dev_groups = cxl_port_attribute_groups,
},
};
int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
struct cxl_dport *parent_dport)
{
struct cxl_port *parent_port = parent_dport->port;
struct cxl_port *endpoint, *iter, *down;
int rc;
/*
* Now that the path to the root is established record all the
* intervening ports in the chain.
*/
for (iter = parent_port, down = NULL; !is_cxl_root(iter);
down = iter, iter = to_cxl_port(iter->dev.parent)) {
struct cxl_ep *ep;
ep = cxl_ep_load(iter, cxlmd);
ep->next = down;
}
/* Note: endpoint port component registers are derived from @cxlds */
endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE,
parent_dport);
if (IS_ERR(endpoint))
return PTR_ERR(endpoint);
rc = cxl_endpoint_autoremove(cxlmd, endpoint);
if (rc)
return rc;
if (!endpoint->dev.driver) {
dev_err(&cxlmd->dev, "%s failed probe\n",
dev_name(&endpoint->dev));
return -ENXIO;
}
return 0;
}
EXPORT_SYMBOL_FOR_MODULES(devm_cxl_add_endpoint, "cxl_mem");
static int __init cxl_port_init(void)
{
return cxl_driver_register(&cxl_port_driver);