[PATCH v2 3/3] cxl/port: Refactor __devm_cxl_add_port() to drop goto pattern

Li Ming
2024-08-26T09:01:23Z

The "goto error" pattern is not recommended, it can be removed via
refactoring. In __devm_cxl_add_port(), there is a 'goto' to call
put_device() for the error cases between device_initialize() and
device_add() to dereference the 'struct device' of a new cxl_port.
The refactoring is introducing a new function called cxl_port_add()
which is used to add the 'struct device' of a new cxl_port to
device hierarchy, moving the functions needing the help of above
'goto' into cxl_port_add(), and using a scope-based resource management
__free() to drop the open coded put_device() and 'goto' for the error
cases.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Li Ming <ming4.li@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
---
drivers/cxl/core/port.c | 59 ++++++++++++++++++++++++-----------------
1 file changed, 35 insertions(+), 24 deletions(-)

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 7b87b5142fa7..053ccd542ab6 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -828,27 +828,20 @@ static void cxl_debugfs_create_dport_dir(struct cxl_dport *dport)
&cxl_einj_inject_fops);
}

-static struct cxl_port *__devm_cxl_add_port(struct device *host,
- struct device *uport_dev,
- resource_size_t component_reg_phys,
- struct cxl_dport *parent_dport)
+static int cxl_port_add(struct cxl_port *port,
+ resource_size_t component_reg_phys,
+ struct cxl_dport *parent_dport)
{
- struct cxl_port *port;
- struct device *dev;
+ struct device *dev __free(put_device) = &port->dev;
int rc;

- port = cxl_port_alloc(uport_dev, parent_dport);
- if (IS_ERR(port))
- return port;
-
- dev = &port->dev;
- if (is_cxl_memdev(uport_dev)) {
- struct cxl_memdev *cxlmd = to_cxl_memdev(uport_dev);
+ if (is_cxl_memdev(port->uport_dev)) {
+ struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
struct cxl_dev_state *cxlds = cxlmd->cxlds;

rc = dev_set_name(dev, "endpoint%d", port->id);
if (rc)
- goto err;
+ return rc;

/*
* The endpoint driver already enumerated the component and RAS
@@ -861,19 +854,41 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
} else if (parent_dport) {
rc = dev_set_name(dev, "port%d", port->id);
if (rc)
- goto err;
+ return rc;

rc = cxl_port_setup_regs(port, component_reg_phys);
if (rc)
- goto err;
- } else
+ return rc;
+ } else {
rc = dev_set_name(dev, "root%d", port->id);
- if (rc)
- goto err;
+ if (rc)
+ return rc;
+ }

rc = device_add(dev);
if (rc)
- goto err;
+ return rc;
+
+ /* Inhibit the cleanup function invoked */
+ dev = NULL;
+ return 0;
+}
+
+static struct cxl_port *__devm_cxl_add_port(struct device *host,
+ struct device *uport_dev,
+ resource_size_t component_reg_phys,
+ struct cxl_dport *parent_dport)
+{
+ struct cxl_port *port;
+ int rc;
+
+ port = cxl_port_alloc(uport_dev, parent_dport);
+ if (IS_ERR(port))
+ return port;
+
+ rc = cxl_port_add(port, component_reg_phys, parent_dport);
+ if (rc)
+ return ERR_PTR(rc);

rc = devm_add_action_or_reset(host, unregister_port, port);
if (rc)
@@ -891,10 +906,6 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
port->pci_latency = cxl_pci_get_latency(to_pci_dev(uport_dev));

return port;
-
-err:
- put_device(dev);
- return ERR_PTR(rc);
}

/**
--
2.40.1