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Subject[PATCH 2/5] fsi: sbefifo: Convert to use the new chardev
Date
This converts FSI sbefifo to use the new fsi-core controlled
chardev allocator and use a real cdev instead of a miscdev.

One side effect is to fix the object lifetime by removing
the use of devm_kzalloc() for something that contains kobjects,
and using proper reference counting.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
drivers/fsi/fsi-sbefifo.c | 84 +++++++++++++++++++++++++--------------
1 file changed, 55 insertions(+), 29 deletions(-)

diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
index 33a5d9a43a07..8a185f53c9d8 100644
--- a/drivers/fsi/fsi-sbefifo.c
+++ b/drivers/fsi/fsi-sbefifo.c
@@ -17,9 +17,8 @@
#include <linux/fs.h>
#include <linux/fsi.h>
#include <linux/fsi-sbefifo.h>
-#include <linux/idr.h>
#include <linux/kernel.h>
-#include <linux/miscdevice.h>
+#include <linux/cdev.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
@@ -118,11 +117,11 @@ struct sbefifo {
uint32_t magic;
#define SBEFIFO_MAGIC 0x53424546 /* "SBEF" */
struct fsi_device *fsi_dev;
- struct miscdevice mdev;
+ struct device dev;
+ struct cdev cdev;
struct mutex lock;
- char name[32];
- int idx;
bool broken;
+ bool dead;
bool async_ffdc;
};

@@ -133,9 +132,9 @@ struct sbefifo_user {
size_t pending_len;
};

-static DEFINE_IDA(sbefifo_ida);
static DEFINE_MUTEX(sbefifo_ffdc_mutex);

+
static void __sbefifo_dump_ffdc(struct device *dev, const __be32 *ffdc,
size_t ffdc_sz, bool internal)
{
@@ -667,6 +666,9 @@ static int __sbefifo_submit(struct sbefifo *sbefifo,
struct device *dev = &sbefifo->fsi_dev->dev;
int rc;

+ if (sbefifo->dead)
+ return -ENODEV;
+
if (cmd_len < 2 || be32_to_cpu(command[0]) != cmd_len) {
dev_vdbg(dev, "Invalid command len %zd (header: %d)\n",
cmd_len, be32_to_cpu(command[0]));
@@ -751,8 +753,7 @@ EXPORT_SYMBOL_GPL(sbefifo_submit);
*/
static int sbefifo_user_open(struct inode *inode, struct file *file)
{
- struct sbefifo *sbefifo = container_of(file->private_data,
- struct sbefifo, mdev);
+ struct sbefifo *sbefifo = container_of(inode->i_cdev, struct sbefifo, cdev);
struct sbefifo_user *user;

user = kzalloc(sizeof(struct sbefifo_user), GFP_KERNEL);
@@ -889,6 +890,14 @@ static const struct file_operations sbefifo_fops = {
.release = sbefifo_user_release,
};

+static void sbefifo_free(struct device *dev)
+{
+ struct sbefifo *sbefifo = container_of(dev, struct sbefifo, dev);
+
+ put_device(&sbefifo->fsi_dev->dev);
+ kfree(sbefifo);
+}
+
/*
* Probe/remove
*/
@@ -900,15 +909,23 @@ static int sbefifo_probe(struct device *dev)
struct device_node *np;
struct platform_device *child;
char child_name[32];
- int rc, child_idx = 0;
+ int rc, didx, child_idx = 0;

dev_dbg(dev, "Found sbefifo device\n");

- sbefifo = devm_kzalloc(dev, sizeof(*sbefifo), GFP_KERNEL);
+ sbefifo = kzalloc(sizeof(*sbefifo), GFP_KERNEL);
if (!sbefifo)
return -ENOMEM;
+
+ /* Grab a reference to the device (parent of our cdev), we'll drop it later */
+ if (!get_device(dev)) {
+ return -ENODEV;
+ kfree(sbefifo);
+ }
+
sbefifo->magic = SBEFIFO_MAGIC;
sbefifo->fsi_dev = fsi_dev;
+ dev_set_drvdata(dev, sbefifo);
mutex_init(&sbefifo->lock);

/*
@@ -919,28 +936,30 @@ static int sbefifo_probe(struct device *dev)
if (rc && rc != -ESHUTDOWN)
dev_err(dev, "Initial HW cleanup failed, will retry later\n");

- sbefifo->idx = ida_simple_get(&sbefifo_ida, 1, INT_MAX, GFP_KERNEL);
- snprintf(sbefifo->name, sizeof(sbefifo->name), "sbefifo%d",
- sbefifo->idx);
+ /* Create chardev for userspace access */
+ sbefifo->dev.type = &fsi_cdev_type;
+ sbefifo->dev.parent = dev;
+ sbefifo->dev.release = sbefifo_free;
+ device_initialize(&sbefifo->dev);

- dev_set_drvdata(dev, sbefifo);
+ /* Allocate a minor in the FSI space */
+ rc = fsi_get_new_minor(fsi_dev, fsi_dev_sbefifo, &sbefifo->dev.devt, &didx);
+ if (rc)
+ goto err;

- /* Create misc chardev for userspace access */
- sbefifo->mdev.minor = MISC_DYNAMIC_MINOR;
- sbefifo->mdev.fops = &sbefifo_fops;
- sbefifo->mdev.name = sbefifo->name;
- sbefifo->mdev.parent = dev;
- rc = misc_register(&sbefifo->mdev);
+ dev_set_name(&sbefifo->dev, "sbefifo%d", didx);
+ cdev_init(&sbefifo->cdev, &sbefifo_fops);
+ rc = cdev_device_add(&sbefifo->cdev, &sbefifo->dev);
if (rc) {
- dev_err(dev, "Failed to register miscdevice: %d\n", rc);
- ida_simple_remove(&sbefifo_ida, sbefifo->idx);
- return rc;
+ dev_err(dev, "Error %d creating char device %s\n",
+ rc, dev_name(&sbefifo->dev));
+ goto err_free_minor;
}

/* Create platform devs for dts child nodes (occ, etc) */
for_each_available_child_of_node(dev->of_node, np) {
snprintf(child_name, sizeof(child_name), "%s-dev%d",
- sbefifo->name, child_idx++);
+ dev_name(&sbefifo->dev), child_idx++);
child = of_platform_device_create(np, child_name, dev);
if (!child)
dev_warn(dev, "failed to create child %s dev\n",
@@ -948,6 +967,11 @@ static int sbefifo_probe(struct device *dev)
}

return 0;
+ err_free_minor:
+ fsi_free_minor(sbefifo->dev.devt);
+ err:
+ put_device(&sbefifo->dev);
+ return rc;
}

static int sbefifo_unregister_child(struct device *dev, void *data)
@@ -967,10 +991,14 @@ static int sbefifo_remove(struct device *dev)

dev_dbg(dev, "Removing sbefifo device...\n");

- misc_deregister(&sbefifo->mdev);
- device_for_each_child(dev, NULL, sbefifo_unregister_child);
+ mutex_lock(&sbefifo->lock);
+ sbefifo->dead = true;
+ mutex_unlock(&sbefifo->lock);

- ida_simple_remove(&sbefifo_ida, sbefifo->idx);
+ cdev_device_del(&sbefifo->cdev, &sbefifo->dev);
+ fsi_free_minor(sbefifo->dev.devt);
+ device_for_each_child(dev, NULL, sbefifo_unregister_child);
+ put_device(&sbefifo->dev);

return 0;
}
@@ -1001,8 +1029,6 @@ static int sbefifo_init(void)
static void sbefifo_exit(void)
{
fsi_driver_unregister(&sbefifo_drv);
-
- ida_destroy(&sbefifo_ida);
}

module_init(sbefifo_init);
--
2.17.1
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