[resend, PATCH v1 0/3] parport: Switch to some modern APIs

[resend, PATCH v1 0/3] parport: Switch to some modern APIs

[Andy Shevchenko]

This is a set of ad-hoc refactorings and cleanups to the parport driver.

In v1,resent:
- resent with Greg KH in Cc list

Initial contribution have been seen here 6 weeks ago:
https://lore.kernel.org/r/20230901134250.1172990-1-andriy.shevchenko@linux.intel.com

Andy Shevchenko (3):
  parport: Use kasprintf() instead of fixed buffer formatting
  parport: Use list_for_each() helper
  parport: Drop unneeded NULL or 0 assignments

 drivers/parport/procfs.c | 53 +++++++---------------------------------
 drivers/parport/share.c  | 25 ++++++++-----------
 include/linux/parport.h  |  2 --
 3 files changed, 19 insertions(+), 61 deletions(-)

-- 
2.40.0.1.gaa8946217a0b

[resend, PATCH v1 1/3] parport: Use kasprintf() instead of fixed buffer formatting

[Andy Shevchenko]

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>
---
 drivers/parport/procfs.c | 53 +++++++---------------------------------
 drivers/parport/share.c  | 15 +++++-------
 include/linux/parport.h  |  2 --
 3 files changed, 15 insertions(+), 55 deletions(-)

diff --git a/drivers/parport/procfs.c b/drivers/parport/procfs.c
index 532d5cbbd344..bd388560ed59 100644
--- 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)
@@ -423,8 +416,7 @@ 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)
@@ -440,35 +432,23 @@ int parport_proc_register(struct parport *port)
 #endif /* IEEE 1284 support */
 	}
 
-	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;
 	}
 
@@ -508,34 +488,22 @@ 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);
@@ -548,9 +516,6 @@ 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 2d46b1d4fd69..8037bcd07bcf 100644
--- 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 999eddd619b7..fff39bc30629 100644
--- 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 */
-- 
2.40.0.1.gaa8946217a0b

[resend, PATCH v1 2/3] parport: Use list_for_each() helper

[Andy Shevchenko]

Convert hard to read custom code to list_for_each().
No functional changes intended.

Note, we may not use list_for_each_entry() as at the end of the list
the iterator will point to an invalid entry and may not be dereferenced.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/parport/share.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 8037bcd07bcf..38780f6a9119 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -469,9 +469,11 @@ struct parport *parport_register_port(unsigned long base, int irq, int dma,
 	/* Search for the lowest free parport number. */
 
 	spin_lock(&full_list_lock);
-	for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
+	num = 0;
+	list_for_each(l, &all_ports) {
 		struct parport *p = list_entry(l, struct parport, full_list);
-		if (p->number != num)
+
+		if (p->number != num++)
 			break;
 	}
 	tmp->portnum = tmp->number = num;
-- 
2.40.0.1.gaa8946217a0b

[resend, PATCH v1 3/3] parport: Drop unneeded NULL or 0 assignments

[Andy Shevchenko]

kzalloc() gives us a zeroed memory, no need to explicitly assing 0 or
NULL or similar to the members of the data structure that has been
allocated with the above mentioned API.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/parport/share.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 38780f6a9119..a9a9cb0477ea 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -449,13 +449,9 @@ struct parport *parport_register_port(unsigned long base, int irq, int dma,
 	tmp->irq = irq;
 	tmp->dma = dma;
 	tmp->muxport = tmp->daisy = tmp->muxsel = -1;
-	tmp->modes = 0;
 	INIT_LIST_HEAD(&tmp->list);
-	tmp->devices = tmp->cad = NULL;
-	tmp->flags = 0;
 	tmp->ops = ops;
 	tmp->physport = tmp;
-	memset(tmp->probe_info, 0, 5 * sizeof(struct parport_device_info));
 	rwlock_init(&tmp->cad_lock);
 	spin_lock_init(&tmp->waitlist_lock);
 	spin_lock_init(&tmp->pardevice_lock);
-- 
2.40.0.1.gaa8946217a0b

Re: [resend, PATCH v1 0/3] parport: Switch to some modern APIs

[Luis Chamberlain]

On Mon, Oct 16, 2023 at 04:31:32PM +0300, Andy Shevchenko wrote:
> This is a set of ad-hoc refactorings and cleanups to the parport driver.
> 
> In v1,resent:
> - resent with Greg KH in Cc list
> 
> Initial contribution have been seen here 6 weeks ago:
> https://lore.kernel.org/r/20230901134250.1172990-1-andriy.shevchenko@linux.intel.com
> 
> Andy Shevchenko (3):
>   parport: Use kasprintf() instead of fixed buffer formatting
>   parport: Use list_for_each() helper
>   parport: Drop unneeded NULL or 0 assignments

Nice cleanup!

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis