From: Ira Weiny <ira.weiny@intel.com>
To: Li Ming <ming4.li@intel.com>, <dave@stgolabs.net>,
<jonathan.cameron@huawei.com>, <dave.jiang@intel.com>,
<alison.schofield@intel.com>, <vishal.l.verma@intel.com>,
<ira.weiny@intel.com>, <dan.j.williams@intel.com>
Cc: <linux-cxl@vger.kernel.org>, Li Ming <ming4.li@intel.com>
Subject: Re: [PATCH 2/3] cxl/port: Use scoped_guard() to drop device_lock()/unlock pair
Date: Wed, 21 Aug 2024 16:49:57 -0500 [thread overview]
Message-ID: <66c66105891fe_1719d2946b@iweiny-mobl.notmuch> (raw)
In-Reply-To: <20240813070552.3353530-2-ming4.li@intel.com>
Li Ming wrote:
> A device_lock() and device_unlock() pair can be replaced by a
> scope-based resource management function scoped_guard() which can make
> the code more readable and safer. Some device_lock() and device_unlock()
> pairs in CXL subsystem can be simply replaced by a scoped_guard().
>
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Li Ming <ming4.li@intel.com>
> ---
> drivers/cxl/core/mbox.c | 26 ++++++------
> drivers/cxl/core/port.c | 87 ++++++++++++++++++---------------------
> drivers/cxl/core/region.c | 25 ++++++-----
> drivers/cxl/mem.c | 22 +++++-----
> drivers/cxl/pmem.c | 16 ++++---
> 5 files changed, 82 insertions(+), 94 deletions(-)
>
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index e5cdeafdf76e..a8ab5f2697be 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -1214,19 +1214,19 @@ int cxl_mem_sanitize(struct cxl_memdev *cxlmd, u16 cmd)
> int rc;
>
> /* synchronize with cxl_mem_probe() and decoder write operations */
> - device_lock(&cxlmd->dev);
> - endpoint = cxlmd->endpoint;
> - down_read(&cxl_region_rwsem);
> - /*
> - * Require an endpoint to be safe otherwise the driver can not
> - * be sure that the device is unmapped.
> - */
> - if (endpoint && cxl_num_decoders_committed(endpoint) == 0)
> - rc = __cxl_mem_sanitize(mds, cmd);
> - else
> - rc = -EBUSY;
> - up_read(&cxl_region_rwsem);
> - device_unlock(&cxlmd->dev);
> + scoped_guard(device, &cxlmd->dev) {
> + endpoint = cxlmd->endpoint;
> + down_read(&cxl_region_rwsem);
> + /*
> + * Require an endpoint to be safe otherwise the driver can not
> + * be sure that the device is unmapped.
> + */
> + if (endpoint && cxl_num_decoders_committed(endpoint) == 0)
> + rc = __cxl_mem_sanitize(mds, cmd);
> + else
> + rc = -EBUSY;
> + up_read(&cxl_region_rwsem);
> + }
>
> return rc;
> }
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 6119cb3ad25c..53e2593daa95 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1260,14 +1260,12 @@ static int add_ep(struct cxl_ep *new)
> struct cxl_port *port = new->dport->port;
> int rc;
>
> - device_lock(&port->dev);
> - if (port->dead) {
> - device_unlock(&port->dev);
> - return -ENXIO;
> + scoped_guard(device, &port->dev) {
> + if (port->dead)
> + return -ENXIO;
> + rc = xa_insert(&port->endpoints, (unsigned long)new->ep, new,
> + GFP_KERNEL);
> }
> - rc = xa_insert(&port->endpoints, (unsigned long)new->ep, new,
> - GFP_KERNEL);
> - device_unlock(&port->dev);
>
> return rc;
> }
> @@ -1393,14 +1391,14 @@ static void delete_endpoint(void *data)
> struct cxl_port *endpoint = cxlmd->endpoint;
> struct device *host = endpoint_host(endpoint);
>
> - device_lock(host);
> - if (host->driver && !endpoint->dead) {
> - devm_release_action(host, cxl_unlink_parent_dport, endpoint);
> - devm_release_action(host, cxl_unlink_uport, endpoint);
> - devm_release_action(host, unregister_port, endpoint);
> + scoped_guard(device, host) {
> + if (host->driver && !endpoint->dead) {
> + devm_release_action(host, cxl_unlink_parent_dport, endpoint);
> + devm_release_action(host, cxl_unlink_uport, endpoint);
> + devm_release_action(host, unregister_port, endpoint);
> + }
> + cxlmd->endpoint = NULL;
> }
> - cxlmd->endpoint = NULL;
> - device_unlock(host);
> put_device(&endpoint->dev);
> put_device(host);
> }
> @@ -1562,40 +1560,36 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
> return -EAGAIN;
> }
>
> - device_lock(&parent_port->dev);
> - if (!parent_port->dev.driver) {
> - dev_warn(&cxlmd->dev,
> - "port %s:%s disabled, failed to enumerate CXL.mem\n",
> - dev_name(&parent_port->dev), dev_name(uport_dev));
> - port = ERR_PTR(-ENXIO);
> - goto out;
> - }
> + scoped_guard(device, &parent_port->dev) {
> + if (!parent_port->dev.driver) {
> + dev_warn(&cxlmd->dev,
> + "port %s:%s disabled, failed to enumerate CXL.mem\n",
> + dev_name(&parent_port->dev), dev_name(uport_dev));
> + return -ENXIO;
> + }
>
> - port = find_cxl_port_at(parent_port, dport_dev, &dport);
> - if (!port) {
> - component_reg_phys = find_component_registers(uport_dev);
> - port = devm_cxl_add_port(&parent_port->dev, uport_dev,
> - component_reg_phys, parent_dport);
> - /* retry find to pick up the new dport information */
> - if (!IS_ERR(port))
> + port = find_cxl_port_at(parent_port, dport_dev, &dport);
> + if (!port) {
> + component_reg_phys = find_component_registers(uport_dev);
> + port = devm_cxl_add_port(&parent_port->dev, uport_dev,
> + component_reg_phys, parent_dport);
> + if (IS_ERR(port))
> + return PTR_ERR(port);
> +
> + /* retry find to pick up the new dport information */
> port = find_cxl_port_at(parent_port, dport_dev, &dport);
Can this call to find_cxl_port_at() fail?
> + }
> }
> -out:
> - device_unlock(&parent_port->dev);
>
> - if (IS_ERR(port))
^^^^^^^^^^^^
Does this need to be checked above?
It seems like the logic is changing for the call to cxl_add_ep() but it
might be ok?
Ira
> - rc = PTR_ERR(port);
> - else {
> - dev_dbg(&cxlmd->dev, "add to new port %s:%s\n",
> - dev_name(&port->dev), dev_name(port->uport_dev));
> - rc = cxl_add_ep(dport, &cxlmd->dev);
> - if (rc == -EBUSY) {
> - /*
> - * "can't" happen, but this error code means
> - * something to the caller, so translate it.
> - */
> - rc = -ENXIO;
> - }
> + dev_dbg(&cxlmd->dev, "add to new port %s:%s\n",
> + dev_name(&port->dev), dev_name(port->uport_dev));
> + rc = cxl_add_ep(dport, &cxlmd->dev);
> + if (rc == -EBUSY) {
> + /*
> + * "can't" happen, but this error code means
> + * something to the caller, so translate it.
> + */
> + rc = -ENXIO;
> }
>
> return rc;
> @@ -1986,9 +1980,8 @@ int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map)
>
> port = to_cxl_port(cxld->dev.parent);
>
> - device_lock(&port->dev);
> - rc = cxl_decoder_add_locked(cxld, target_map);
> - device_unlock(&port->dev);
> + scoped_guard(device, &port->dev)
> + rc = cxl_decoder_add_locked(cxld, target_map);
>
> return rc;
> }
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 21ad5f242875..a3ce7cbe5c6c 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3094,11 +3094,11 @@ static void cxlr_release_nvdimm(void *_cxlr)
> struct cxl_region *cxlr = _cxlr;
> struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
>
> - device_lock(&cxl_nvb->dev);
> - if (cxlr->cxlr_pmem)
> - devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
> - cxlr->cxlr_pmem);
> - device_unlock(&cxl_nvb->dev);
> + scoped_guard(device, &cxl_nvb->dev) {
> + if (cxlr->cxlr_pmem)
> + devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
> + cxlr->cxlr_pmem);
> + }
> cxlr->cxl_nvb = NULL;
> put_device(&cxl_nvb->dev);
> }
> @@ -3134,14 +3134,13 @@ static int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
> dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
> dev_name(dev));
>
> - device_lock(&cxl_nvb->dev);
> - if (cxl_nvb->dev.driver)
> - rc = devm_add_action_or_reset(&cxl_nvb->dev,
> - cxlr_pmem_unregister, cxlr_pmem);
> - else
> - rc = -ENXIO;
> - device_unlock(&cxl_nvb->dev);
> -
> + scoped_guard(device, &cxl_nvb->dev) {
> + if (cxl_nvb->dev.driver)
> + rc = devm_add_action_or_reset(&cxl_nvb->dev,
> + cxlr_pmem_unregister, cxlr_pmem);
> + else
> + rc = -ENXIO;
> + }
> if (rc)
> goto err_bridge;
>
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index ab9b8ab8df44..ae94018a01bd 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -168,19 +168,17 @@ static int cxl_mem_probe(struct device *dev)
>
> cxl_setup_parent_dport(dev, dport);
>
> - device_lock(endpoint_parent);
> - if (!endpoint_parent->driver) {
> - dev_err(dev, "CXL port topology %s not enabled\n",
> - dev_name(endpoint_parent));
> - rc = -ENXIO;
> - goto unlock;
> - }
> + scoped_guard(device, endpoint_parent) {
> + if (!endpoint_parent->driver) {
> + dev_err(dev, "CXL port topology %s not enabled\n",
> + dev_name(endpoint_parent));
> + return -ENXIO;
> + }
>
> - rc = devm_cxl_add_endpoint(endpoint_parent, cxlmd, dport);
> -unlock:
> - device_unlock(endpoint_parent);
> - if (rc)
> - return rc;
> + rc = devm_cxl_add_endpoint(endpoint_parent, cxlmd, dport);
> + if (rc)
> + return rc;
> + }
>
> /*
> * The kernel may be operating out of CXL memory on this device,
> diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> index 4ef93da22335..647c7e25ef3a 100644
> --- a/drivers/cxl/pmem.c
> +++ b/drivers/cxl/pmem.c
> @@ -233,15 +233,13 @@ static int detach_nvdimm(struct device *dev, void *data)
> if (!is_cxl_nvdimm(dev))
> return 0;
>
> - device_lock(dev);
> - if (!dev->driver)
> - goto out;
> -
> - cxl_nvd = to_cxl_nvdimm(dev);
> - if (cxl_nvd->cxlmd && cxl_nvd->cxlmd->cxl_nvb == data)
> - release = true;
> -out:
> - device_unlock(dev);
> + scoped_guard(device, dev) {
> + if (dev->driver) {
> + cxl_nvd = to_cxl_nvdimm(dev);
> + if (cxl_nvd->cxlmd && cxl_nvd->cxlmd->cxl_nvb == data)
> + release = true;
> + }
> + }
> if (release)
> device_release_driver(dev);
> return 0;
> --
> 2.40.1
>
next prev parent reply other threads:[~2024-08-21 21:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-13 7:05 [PATCH 1/3] cxl/port: Use __free() to drop put_device() for cxl_port Li Ming
2024-08-13 7:05 ` [PATCH 2/3] cxl/port: Use scoped_guard() to drop device_lock()/unlock pair Li Ming
2024-08-21 21:49 ` Ira Weiny [this message]
2024-08-22 1:47 ` Li, Ming4
2024-08-13 7:05 ` [PATCH 3/3] cxl/port: Refactor __devm_cxl_add_port() to drop goto pattern Li Ming
2024-08-21 22:01 ` Ira Weiny
2024-08-22 2:07 ` Li, Ming4
2024-08-21 21:37 ` [PATCH 1/3] cxl/port: Use __free() to drop put_device() for cxl_port Ira Weiny
2024-08-22 1:26 ` Li, Ming4
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