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Subject[PATCH v4 2/8] parport: Remove register_sysctl_table from parport_proc_register
Date
This is part of the general push to deprecate register_sysctl_paths and
register_sysctl_table. Register dev/parport/PORTNAME and
dev/parport/PORTNAME/devices. Temporary allocation for name is freed at
the end of the function. Remove all the struct elements that are no
longer used in the parport_device_sysctl_template struct. Add parport
specific defines that hide the base path sizes.

To make sure the resulting directory structure did not change we
made sure that `find /proc/sys/dev/ | sha1sum` was the same before and
after the change.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202305150948.pHgIh7Ql-lkp@intel.com/
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202305150948.pHgIh7Ql-lkp@intel.com/
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
drivers/parport/procfs.c | 93 ++++++++++++++++++++++++++--------------
1 file changed, 61 insertions(+), 32 deletions(-)

diff --git a/drivers/parport/procfs.c b/drivers/parport/procfs.c
index d740eba3c099..28a37e0ef98c 100644
--- a/drivers/parport/procfs.c
+++ b/drivers/parport/procfs.c
@@ -32,6 +32,13 @@
#define PARPORT_MAX_TIMESLICE_VALUE ((unsigned long) HZ)
#define PARPORT_MIN_SPINTIME_VALUE 1
#define PARPORT_MAX_SPINTIME_VALUE 1000
+/*
+ * PARPORT_BASE_* is the size of the known parts of the sysctl path
+ * in dev/partport/%s/devices/%s. "dev/parport/"(12), "/devices/"(9
+ * and null char(1).
+ */
+#define PARPORT_BASE_PATH_SIZE 13
+#define PARPORT_BASE_DEVICES_PATH_SIZE 22

static int do_active_device(struct ctl_table *table, int write,
void *result, size_t *lenp, loff_t *ppos)
@@ -260,9 +267,6 @@ struct parport_sysctl_table {
struct ctl_table_header *sysctl_header;
struct ctl_table vars[12];
struct ctl_table device_dir[2];
- struct ctl_table port_dir[2];
- struct ctl_table parport_dir[2];
- struct ctl_table dev_dir[2];
};

static const struct parport_sysctl_table parport_sysctl_template = {
@@ -305,7 +309,6 @@ static const struct parport_sysctl_table parport_sysctl_template = {
.mode = 0444,
.proc_handler = do_hardware_modes
},
- PARPORT_DEVICES_ROOT_DIR,
#ifdef CONFIG_PARPORT_1284
{
.procname = "autoprobe",
@@ -355,18 +358,6 @@ static const struct parport_sysctl_table parport_sysctl_template = {
},
{}
},
- {
- PARPORT_PORT_DIR(NULL),
- {}
- },
- {
- PARPORT_PARPORT_DIR(NULL),
- {}
- },
- {
- PARPORT_DEV_DIR(NULL),
- {}
- }
};

struct parport_device_sysctl_table
@@ -473,11 +464,13 @@ parport_default_sysctl_table = {
}
};

-
int parport_proc_register(struct parport *port)
{
struct parport_sysctl_table *t;
- int i;
+ struct ctl_table_header *devices_h;
+ char *tmp_dir_path;
+ size_t tmp_path_len, port_name_len;
+ int bytes_written, i, err = 0;

t = kmemdup(&parport_sysctl_template, sizeof(*t), GFP_KERNEL);
if (t == NULL)
@@ -485,28 +478,64 @@ int parport_proc_register(struct parport *port)

t->device_dir[0].extra1 = port;

- for (i = 0; i < 5; i++)
- t->vars[i].extra1 = port;
-
t->vars[0].data = &port->spintime;
- t->vars[5].child = t->device_dir;
-
- for (i = 0; i < 5; i++)
- t->vars[6 + i].extra2 = &port->probe_info[i];
+ for (i = 0; i < 5; i++) {
+ t->vars[i].extra1 = port;
+ t->vars[5 + i].extra2 = &port->probe_info[i];
+ }

- t->port_dir[0].procname = port->name;
+ port_name_len = strnlen(port->name, PARPORT_NAME_MAX_LEN);
+ /*
+ * Allocate a buffer for two paths: dev/parport/PORT and dev/parport/PORT/devices.
+ * We calculate for the second as that will give us enough for the first.
+ */
+ tmp_path_len = PARPORT_BASE_DEVICES_PATH_SIZE + port_name_len;
+ tmp_dir_path = kzalloc(tmp_path_len, GFP_KERNEL);
+ if (!tmp_dir_path) {
+ err = -ENOMEM;
+ goto exit_free_t;
+ }

- t->port_dir[0].child = t->vars;
- t->parport_dir[0].child = t->port_dir;
- t->dev_dir[0].child = t->parport_dir;
+ bytes_written = snprintf(tmp_dir_path, tmp_path_len,
+ "dev/parport/%s/devices", port->name);
+ if (tmp_path_len <= bytes_written) {
+ err = -ENOENT;
+ goto exit_free_tmp_dir_path;
+ }
+ devices_h = register_sysctl(tmp_dir_path, t->device_dir);
+ if (devices_h == NULL) {
+ err = -ENOENT;
+ goto exit_free_tmp_dir_path;
+ }

- t->sysctl_header = register_sysctl_table(t->dev_dir);
+ tmp_path_len = PARPORT_BASE_PATH_SIZE + port_name_len;
+ bytes_written = snprintf(tmp_dir_path, tmp_path_len,
+ "dev/parport/%s", port->name);
+ if (tmp_path_len <= bytes_written) {
+ err = -ENOENT;
+ goto unregister_devices_h;
+ }
+
+ t->sysctl_header = register_sysctl(tmp_dir_path, t->vars);
if (t->sysctl_header == NULL) {
- kfree(t);
- t = NULL;
+ err = -ENOENT;
+ goto unregister_devices_h;
}
+
port->sysctl_table = t;
+
+ kfree(tmp_dir_path);
return 0;
+
+unregister_devices_h:
+ unregister_sysctl_table(devices_h);
+
+exit_free_tmp_dir_path:
+ kfree(tmp_dir_path);
+
+exit_free_t:
+ kfree(t);
+ return err;
}

int parport_proc_unregister(struct parport *port)
--
2.30.2
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