parport: Use kasprintf() instead of fixed buffer formatting

Improve readability and maintainability by replacing a hardcoded string
allocation and formatting by the use of the kasprintf() helper.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231016133135.1203643-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/parport/procfs.c b/drivers/parport/procfs.c
index 4e5b972c3e2633527287e1ee663224654f8d55f9..7aa99c65b934fe13dffb869ba2fbfa3b47477a1e 100644 (file)
--- a/drivers/parport/procfs.c
+++ b/drivers/parport/procfs.c
@@ -32,13 +32,6 @@
 #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)
@@ -431,8 +424,7 @@ int parport_proc_register(struct parport *port)
 {
        struct parport_sysctl_table *t;
        char *tmp_dir_path;
-       size_t tmp_path_len, port_name_len;
-       int bytes_written, i, err = 0;
+       int i, err = 0;
 
        t = kmemdup(&parport_sysctl_template, sizeof(*t), GFP_KERNEL);
        if (t == NULL)
@@ -446,35 +438,23 @@ int parport_proc_register(struct parport *port)
                t->vars[5 + i].extra2 = &port->probe_info[i];
        }
 
-       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);
+       tmp_dir_path = kasprintf(GFP_KERNEL, "dev/parport/%s/devices", port->name);
        if (!tmp_dir_path) {
                err = -ENOMEM;
                goto exit_free_t;
        }
 
-       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;
-       }
        t->devices_header = register_sysctl(tmp_dir_path, t->device_dir);
        if (t->devices_header == NULL) {
                err = -ENOENT;
                goto  exit_free_tmp_dir_path;
        }
 
-       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;
+       kfree(tmp_dir_path);
+
+       tmp_dir_path = kasprintf(GFP_KERNEL, "dev/parport/%s", port->name);
+       if (!tmp_dir_path) {
+               err = -ENOMEM;
                goto unregister_devices_h;
        }
 
@@ -514,34 +494,22 @@ int parport_proc_unregister(struct parport *port)
 
 int parport_device_proc_register(struct pardevice *device)
 {
-       int bytes_written, err = 0;
        struct parport_device_sysctl_table *t;
        struct parport * port = device->port;
-       size_t port_name_len, device_name_len, tmp_dir_path_len;
        char *tmp_dir_path;
+       int err = 0;
        
        t = kmemdup(&parport_device_sysctl_template, sizeof(*t), GFP_KERNEL);
        if (t == NULL)
                return -ENOMEM;
 
-       port_name_len = strnlen(port->name, PARPORT_NAME_MAX_LEN);
-       device_name_len = strnlen(device->name, PATH_MAX);
-
        /* Allocate a buffer for two paths: dev/parport/PORT/devices/DEVICE. */
-       tmp_dir_path_len = PARPORT_BASE_DEVICES_PATH_SIZE + port_name_len + device_name_len;
-       tmp_dir_path = kzalloc(tmp_dir_path_len, GFP_KERNEL);
+       tmp_dir_path = kasprintf(GFP_KERNEL, "dev/parport/%s/devices/%s", port->name, device->name);
        if (!tmp_dir_path) {
                err = -ENOMEM;
                goto exit_free_t;
        }
 
-       bytes_written = snprintf(tmp_dir_path, tmp_dir_path_len, "dev/parport/%s/devices/%s",
-                                port->name, device->name);
-       if (tmp_dir_path_len <= bytes_written) {
-               err = -ENOENT;
-               goto exit_free_path;
-       }
-
        t->vars[0].data = &device->timeslice;
 
        t->sysctl_header = register_sysctl(tmp_dir_path, t->vars);
@@ -554,9 +522,6 @@ int parport_device_proc_register(struct pardevice *device)
        kfree(tmp_dir_path);
        return 0;
 
-exit_free_path:
-       kfree(tmp_dir_path);
-
 exit_free_t:
        kfree(t);
 

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 2d46b1d4fd6953eb5655c3a062f0a95a6e465ceb..8037bcd07bcf94956b7cf55fd553911f7336c064 100644 (file)
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -438,7 +438,6 @@ struct parport *parport_register_port(unsigned long base, int irq, int dma,
        struct parport *tmp;
        int num;
        int device;
-       char *name;
        int ret;
 
        tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
@@ -467,11 +466,6 @@ struct parport *parport_register_port(unsigned long base, int irq, int dma,
        atomic_set(&tmp->ref_count, 1);
        INIT_LIST_HEAD(&tmp->full_list);
 
-       name = kmalloc(PARPORT_NAME_MAX_LEN, GFP_KERNEL);
-       if (!name) {
-               kfree(tmp);
-               return NULL;
-       }
        /* Search for the lowest free parport number. */
 
        spin_lock(&full_list_lock);
@@ -487,11 +481,14 @@ struct parport *parport_register_port(unsigned long base, int irq, int dma,
        /*
         * Now that the portnum is known finish doing the Init.
         */
-       sprintf(name, "parport%d", tmp->portnum = tmp->number);
-       tmp->name = name;
+       tmp->name = kasprintf(GFP_KERNEL, "parport%d", tmp->portnum);
+       if (!tmp->name) {
+               kfree(tmp);
+               return NULL;
+       }
+       dev_set_name(&tmp->bus_dev, tmp->name);
        tmp->bus_dev.bus = &parport_bus_type;
        tmp->bus_dev.release = free_port;
-       dev_set_name(&tmp->bus_dev, name);
        tmp->bus_dev.type = &parport_device_type;
 
        for (device = 0; device < 5; device++)

diff --git a/include/linux/parport.h b/include/linux/parport.h
index 999eddd619b7279866c1190c05aca8214862e1b8..fff39bc3062905fc9072ecea60ca90f6806676b5 100644 (file)
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -180,8 +180,6 @@ struct ieee1284_info {
        struct semaphore irq;
 };
 
-#define PARPORT_NAME_MAX_LEN 15
-
 /* A parallel port */
 struct parport {
        unsigned long base;     /* base address */