Skip to contentSkip to conversation

TM6000: Adjustments for some function implementations

PATCH New SF Markus Elfring 1 participant 10 messages Sep 15, 2017

Subsystems (2)
Media (V4L/DVB) Kernel janitors
lore
Share & tools
lore

SF Markus Elfring

author
#0 lore raw

cover TM6000: Adjustments for some function implementations

From: Markus Elfring <[email protected]>
Date: Fri, 15 Sep 2017 08:24:56 +0200

Some update suggestions were taken into account
from static source code analysis.

Markus Elfring (9):
Delete seven error messages for a failed memory allocation Adjust seven checks for null pointers
Use common error handling code in tm6000_usb_probe()
One function call less in tm6000_usb_probe() after error detection Delete an unnecessary variable initialisation in tm6000_usb_probe() Use common error handling code in tm6000_cards_setup() Improve a size determination in dvb_init()
Use common error handling code in tm6000_start_stream() Use common error handling code in tm6000_prepare_isoc()

 drivers/media/usb/tm6000/tm6000-cards.c | 36 ++++++++++++++++-----------------
 drivers/media/usb/tm6000/tm6000-dvb.c   | 24 +++++++++++-----------
 drivers/media/usb/tm6000/tm6000-input.c |  2 +-
 drivers/media/usb/tm6000/tm6000-video.c | 30 +++++++++++----------------
 4 files changed, 42 insertions(+), 50 deletions(-)
Signature · 1 line
2.14.1
author
#1 lore raw

PATCH 1/9 tm6000: Delete seven error messages for a failed memory allocation

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 14:34:39 +0200

Omit extra messages for a memory allocation failure in these functions.

This issue was detected by using the Coccinelle software.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c |  1 -
 drivers/media/usb/tm6000/tm6000-dvb.c   |  5 +----
 drivers/media/usb/tm6000/tm6000-video.c | 13 +++----------
 3 files changed, 4 insertions(+), 15 deletions(-)
drivers/media/usb/tm6000/tm6000-cards.c +0 -1
index 2537643a1808..817bae8cb6a1 100644
@@ -1210,4 +1210,3 @@ static int tm6000_usb_probe(struct usb_interface *interface,
-		printk(KERN_ERR "tm6000" ": out of memory!\n");
 		usb_put_dev(usbdev);
 		return -ENOMEM;
 	}
drivers/media/usb/tm6000/tm6000-dvb.c +1 -4
index 097ac321b7e1..61a4e0a52716 100644
@@ -137,5 +137,4 @@ static int tm6000_start_stream(struct tm6000_core *dev)
 		usb_free_urb(dvb->bulk_urb);
-		printk(KERN_ERR "tm6000: couldn't allocate transfer buffer!\n");
 		return -ENOMEM;
 	}
 

@@ -403,7 +402,5 @@ static int dvb_init(struct tm6000_core *dev)
-	if (!dvb) {
-		printk(KERN_INFO "Cannot allocate memory\n");
+	if (!dvb)
 		return -ENOMEM;
-	}
 
 	dev->dvb = dvb;
drivers/media/usb/tm6000/tm6000-video.c +3 -10
index ec8c4d2534dc..701494e72edc 100644
@@ -477,13 +477,9 @@ static int tm6000_alloc_urb_buffers(struct tm6000_core *dev)
-	if (!dev->urb_buffer) {
-		tm6000_err("cannot allocate memory for urb buffers\n");
+	if (!dev->urb_buffer)
 		return -ENOMEM;
-	}
 
 	dev->urb_dma = kmalloc(sizeof(dma_addr_t *)*num_bufs, GFP_KERNEL);
-	if (!dev->urb_dma) {
-		tm6000_err("cannot allocate memory for urb dma pointers\n");
+	if (!dev->urb_dma)
 		return -ENOMEM;
-	}
 
 	for (i = 0; i < num_bufs; i++) {
 		dev->urb_buffer[i] = usb_alloc_coherent(

@@ -601,12 +597,9 @@ static int tm6000_prepare_isoc(struct tm6000_core *dev)
-	if (!dev->isoc_ctl.urb) {
-		tm6000_err("cannot alloc memory for usb buffers\n");
+	if (!dev->isoc_ctl.urb)
 		return -ENOMEM;
-	}
 
 	dev->isoc_ctl.transfer_buffer = kmalloc(sizeof(void *)*num_bufs,
 				   GFP_KERNEL);
 	if (!dev->isoc_ctl.transfer_buffer) {
-		tm6000_err("cannot allocate memory for usbtransfer\n");
 		kfree(dev->isoc_ctl.urb);
 		return -ENOMEM;
 	}
Signature · 1 line
2.14.1
author
#2 lore raw

PATCH 2/9 tm6000: Adjust seven checks for null pointers

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 14:51:15 +0200
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The script “checkpatch.pl” pointed information out like the following.

Comparison to NULL could be written …

Thus fix the affected source code places.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c | 2 +-
 drivers/media/usb/tm6000/tm6000-dvb.c   | 6 +++---
 drivers/media/usb/tm6000/tm6000-input.c | 2 +-
 drivers/media/usb/tm6000/tm6000-video.c | 4 ++--
 4 files changed, 7 insertions(+), 7 deletions(-)
drivers/media/usb/tm6000/tm6000-cards.c +1 -1
index 817bae8cb6a1..ef37fb1f05e4 100644
@@ -1206,7 +1206,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 
 	/* Create and initialize dev struct */
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-	if (dev = NULL) {
+	if (!dev) {
 		usb_put_dev(usbdev);
 		return -ENOMEM;
 	}
drivers/media/usb/tm6000/tm6000-dvb.c +3 -3
index 61a4e0a52716..2bc584f75f87 100644
@@ -123,7 +123,7 @@ static int tm6000_start_stream(struct tm6000_core *dev)
 	}
 
 	dvb->bulk_urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (dvb->bulk_urb = NULL)
+	if (!dvb->bulk_urb)
 		return -ENOMEM;
 
 	pipe = usb_rcvbulkpipe(dev->udev, dev->bulk_in.endp->desc.bEndpointAddress

@@ -133,7 +133,7 @@ static int tm6000_start_stream(struct tm6000_core *dev)
 	size = size * 15; /* 512 x 8 or 12 or 15 */
 
 	dvb->bulk_urb->transfer_buffer = kzalloc(size, GFP_KERNEL);
-	if (dvb->bulk_urb->transfer_buffer = NULL) {
+	if (!dvb->bulk_urb->transfer_buffer) {
 		usb_free_urb(dvb->bulk_urb);
 		return -ENOMEM;
 	}

@@ -360,7 +360,7 @@ static void unregister_dvb(struct tm6000_core *dev)
 {
 	struct tm6000_dvb *dvb = dev->dvb;
 
-	if (dvb->bulk_urb != NULL) {
+	if (dvb->bulk_urb) {
 		struct urb *bulk_urb = dvb->bulk_urb;
 
 		kfree(bulk_urb->transfer_buffer);
drivers/media/usb/tm6000/tm6000-input.c +1 -1
index 91889ad9cdd7..397990afe00b 100644
@@ -352,7 +352,7 @@ static int __tm6000_ir_int_start(struct rc_dev *rc)
 	dprintk(1, "IR max size: %d\n", size);
 
 	ir->int_urb->transfer_buffer = kzalloc(size, GFP_ATOMIC);
-	if (ir->int_urb->transfer_buffer = NULL) {
+	if (!ir->int_urb->transfer_buffer) {
 		usb_free_urb(ir->int_urb);
 		return err;
 	}
drivers/media/usb/tm6000/tm6000-video.c +2 -2
index 701494e72edc..0d45f35e1697 100644
@@ -470,7 +470,7 @@ static int tm6000_alloc_urb_buffers(struct tm6000_core *dev)
 	int num_bufs = TM6000_NUM_URB_BUF;
 	int i;
 
-	if (dev->urb_buffer != NULL)
+	if (dev->urb_buffer)
 		return 0;
 
 	dev->urb_buffer = kmalloc(sizeof(void *)*num_bufs, GFP_KERNEL);

@@ -503,7 +503,7 @@ static int tm6000_free_urb_buffers(struct tm6000_core *dev)
 {
 	int i;
 
-	if (dev->urb_buffer = NULL)
+	if (!dev->urb_buffer)
 		return 0;
 
 	for (i = 0; i < TM6000_NUM_URB_BUF; i++) {
Signature · 1 line
2.14.1
author
#3 lore raw

PATCH 3/9 tm6000: Use common error handling code in tm6000_usb_probe()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 16:00:47 +0200

Add a jump target so that a bit of exception handling can be better reused at the end of this function.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
drivers/media/usb/tm6000/tm6000-cards.c +6 -5
index ef37fb1f05e4..e18632056976 100644
@@ -1200,15 +1200,15 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 	nr = find_first_zero_bit(&tm6000_devused, TM6000_MAXBOARDS);
 	if (nr >= TM6000_MAXBOARDS) {
 		printk(KERN_ERR "tm6000: Supports only %i tm60xx boards.\n", TM6000_MAXBOARDS);
-		usb_put_dev(usbdev);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto put_device;
 	}
 
 	/* Create and initialize dev struct */
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev) {
-		usb_put_dev(usbdev);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto put_device;
 	}
 	spin_lock_init(&dev->slock);
 	mutex_init(&dev->usb_lock);

@@ -1331,9 +1331,10 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 	printk(KERN_ERR "tm6000: Error %d while registering\n", rc);
 
 	clear_bit(nr, &tm6000_devused);
-	usb_put_dev(usbdev);
 
 	kfree(dev);
+put_device:
+	usb_put_dev(usbdev);
 	return rc;
 }
Signature · 1 line
2.14.1
author
#4 lore raw

PATCH 4/9 tm6000: One function call less in tm6000_usb_probe() after error detection

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 16:11:55 +0200

* Adjust jump targets so that the function "kfree" will be always called with a non-null pointer.

* Delete an initialisation for the local variable "dev" which became unnecessary with this refactoring.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)
drivers/media/usb/tm6000/tm6000-cards.c +7 -8
index e18632056976..77347541904d 100644
@@ -1184,7 +1184,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 			    const struct usb_device_id *id)
 {
 	struct usb_device *usbdev;
-	struct tm6000_core *dev = NULL;
+	struct tm6000_core *dev;
 	int i, rc = 0;
 	int nr = 0;
 	char *speed;

@@ -1194,7 +1194,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 	/* Selects the proper interface */
 	rc = usb_set_interface(usbdev, 0, 1);
 	if (rc < 0)
-		goto err;
+		goto report_failure;
 
 	/* Check to see next free device and mark as used */
 	nr = find_first_zero_bit(&tm6000_devused, TM6000_MAXBOARDS);

@@ -1312,8 +1312,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 	if (!dev->isoc_in.endp) {
 		printk(KERN_ERR "tm6000: probing error: no IN ISOC endpoint!\n");
 		rc = -ENODEV;
-
-		goto err;
+		goto free_device;
 	}
 
 	/* save our data pointer in this interface device */

@@ -1323,16 +1322,16 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 
 	rc = tm6000_init_dev(dev);
 	if (rc < 0)
-		goto err;
+		goto free_device;
 
 	return 0;
 
-err:
+free_device:
+	kfree(dev);
+report_failure:
 	printk(KERN_ERR "tm6000: Error %d while registering\n", rc);
 
 	clear_bit(nr, &tm6000_devused);
-
-	kfree(dev);
 put_device:
 	usb_put_dev(usbdev);
 	return rc;
Signature · 1 line
2.14.1
author
#5 lore raw

PATCH 5/9 tm6000: Delete an unnecessary variable initialisation in tm6000_usb_probe()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 16:13:56 +0200

The local variable "rc" will be set to an appropriate value a bit later. Thus omit the explicit initialisation at the beginning.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/media/usb/tm6000/tm6000-cards.c +1 -1
index 77347541904d..72dd6b80394f 100644
@@ -1185,7 +1185,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
 {
 	struct usb_device *usbdev;
 	struct tm6000_core *dev;
-	int i, rc = 0;
+	int i, rc;
 	int nr = 0;
 	char *speed;
Signature · 1 line
2.14.1
author
#6 lore raw

PATCH 6/9 tm6000: Use common error handling code in tm6000_cards_setup()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Thu, 14 Sep 2017 16:26:42 +0200

Add a jump target so that a bit of exception handling can be better reused in this function.

This issue was detected by using the Coccinelle software.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-cards.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
drivers/media/usb/tm6000/tm6000-cards.c +3 -4
index 72dd6b80394f..502e0b38b7f1 100644
@@ -872,15 +872,14 @@ int tm6000_cards_setup(struct tm6000_core *dev)
 		for (i = 0; i < 2; i++) {
 			rc = tm6000_set_reg(dev, REQ_03_SET_GET_MCU_PIN,
 						dev->gpio.tuner_reset, 0x00);
-			if (rc < 0) {
-				printk(KERN_ERR "Error %i doing tuner reset\n", rc);
-				return rc;
-			}
+			if (rc < 0)
+				goto report_failure;
 
 			msleep(10); /* Just to be conservative */
 			rc = tm6000_set_reg(dev, REQ_03_SET_GET_MCU_PIN,
 						dev->gpio.tuner_reset, 0x01);
 			if (rc < 0) {
+report_failure:
 				printk(KERN_ERR "Error %i doing tuner reset\n", rc);
 				return rc;
 			}
Signature · 1 line
2.14.1
author
#7 lore raw

PATCH 7/9 tm6000: Improve a size determination in dvb_init()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Fri, 15 Sep 2017 07:33:24 +0200

Replace the specification of a data structure by a pointer dereference as the parameter for the operator "sizeof" to make the corresponding size determination a bit safer according to the Linux coding style convention.

This issue was detected by using the Coccinelle software.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-dvb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/media/usb/tm6000/tm6000-dvb.c +1 -1
index 2bc584f75f87..855874134fcf 100644
@@ -398,7 +398,7 @@ static int dvb_init(struct tm6000_core *dev)
 		return 0;
 	}
 
-	dvb = kzalloc(sizeof(struct tm6000_dvb), GFP_KERNEL);
+	dvb = kzalloc(sizeof(*dvb), GFP_KERNEL);
 	if (!dvb)
 		return -ENOMEM;
Signature · 1 line
2.14.1
author
#8 lore raw

PATCH 8/9 tm6000: Use common error handling code in tm6000_start_stream()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Fri, 15 Sep 2017 07:47:41 +0200

Add a jump target so that a bit of exception handling can be better reused at the end of this function.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-dvb.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
drivers/media/usb/tm6000/tm6000-dvb.c +7 -4
index 855874134fcf..b45e54d5cab9 100644
@@ -134,8 +134,8 @@ static int tm6000_start_stream(struct tm6000_core *dev)
 
 	dvb->bulk_urb->transfer_buffer = kzalloc(size, GFP_KERNEL);
 	if (!dvb->bulk_urb->transfer_buffer) {
-		usb_free_urb(dvb->bulk_urb);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto free_urb;
 	}
 
 	usb_fill_bulk_urb(dvb->bulk_urb, dev->udev, pipe,

@@ -160,11 +160,14 @@ static int tm6000_start_stream(struct tm6000_core *dev)
 									ret);
 
 		kfree(dvb->bulk_urb->transfer_buffer);
-		usb_free_urb(dvb->bulk_urb);
-		return ret;
+		goto free_urb;
 	}
 
 	return 0;
+
+free_urb:
+	usb_free_urb(dvb->bulk_urb);
+	return ret;
 }
 
 static void tm6000_stop_stream(struct tm6000_core *dev)
Signature · 1 line
2.14.1
author
#9 lore raw

PATCH 9/9 tm6000: Use common error handling code in tm6000_prepare_isoc()

In reply to SF Markus Elfring

From: Markus Elfring <[email protected]>
Date: Fri, 15 Sep 2017 08:02:33 +0200

Add a jump target so that a bit of exception handling can be better reused at the end of this function.

Signed-off-by Markus Elfring <[email protected]>
---
 drivers/media/usb/tm6000/tm6000-video.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)
drivers/media/usb/tm6000/tm6000-video.c +7 -6
index 0d45f35e1697..bfdeb41ed3a1 100644
@@ -602,7 +602,5 @@ static int tm6000_prepare_isoc(struct tm6000_core *dev)
-	if (!dev->isoc_ctl.transfer_buffer) {
-		kfree(dev->isoc_ctl.urb);
-		return -ENOMEM;
-	}
+	if (!dev->isoc_ctl.transfer_buffer)
+		goto free_urb;
 
 	dprintk(dev, V4L2_DEBUG_QUEUE, "Allocating %d x %d packets (%d bytes) of %d bytes each to handle %u size\n",
 		    max_packets, num_bufs, sb_size,

@@ -616,7 +614,6 @@ static int tm6000_prepare_isoc(struct tm6000_core *dev)
 		tm6000_free_urb_buffers(dev);
-		kfree(dev->isoc_ctl.urb);
 		kfree(dev->isoc_ctl.transfer_buffer);
-		return -ENOMEM;
+		goto free_urb;
 	}
 
 	/* allocate urbs and transfer buffers */

@@ -646,6 +643,10 @@ static int tm6000_prepare_isoc(struct tm6000_core *dev)
 	}
 
 	return 0;
+
+free_urb:
+	kfree(dev->isoc_ctl.urb);
+	return -ENOMEM;
 }
 
 static int tm6000_start_thread(struct tm6000_core *dev)
Signature · 1 line
2.14.1