[PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[Jesper Juhl]

This patch removes redundant checks for NULL pointer before kfree() in 
drivers/telephony/


Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
---

 drivers/telephony/ixj.c |   48 +++++++++++++++++-------------------------------
 1 files changed, 17 insertions(+), 31 deletions(-)

diff -upr linux-2.6.12-rc3-mm3-orig/drivers/telephony/ixj.c linux-2.6.12-rc3-mm3/drivers/telephony/ixj.c
--- linux-2.6.12-rc3-mm3-orig/drivers/telephony/ixj.c	2005-05-06 23:21:17.000000000 +0200
+++ linux-2.6.12-rc3-mm3/drivers/telephony/ixj.c	2005-05-07 02:53:15.000000000 +0200
@@ -329,10 +329,8 @@ static IXJ *ixj_alloc()
 
 static void ixj_fsk_free(IXJ *j)
 {
-	if(j->fskdata != NULL) {
-		kfree(j->fskdata);
-		j->fskdata = NULL;
-	}
+	kfree(j->fskdata);
+	j->fskdata = NULL;
 }
 
 static void ixj_fsk_alloc(IXJ *j)
@@ -3869,11 +3867,9 @@ static int set_rec_codec(IXJ *j, int rat
 	default:
 		j->rec_frame_size = 0;
 		j->rec_mode = -1;
-		if (j->read_buffer) {
-			kfree(j->read_buffer);
-			j->read_buffer = NULL;
-			j->read_buffer_size = 0;
-		}
+		kfree(j->read_buffer);
+		j->read_buffer = NULL;
+		j->read_buffer_size = 0;
 		retval = 1;
 		break;
 	}
@@ -3994,11 +3990,9 @@ static void ixj_record_stop(IXJ *j)
 	if(ixjdebug & 0x0002)
 		printk("IXJ %d Stopping Record Codec %d at %ld\n", j->board, j->rec_codec, jiffies);
 
-	if (j->read_buffer) {
-		kfree(j->read_buffer);
-		j->read_buffer = NULL;
-		j->read_buffer_size = 0;
-	}
+	kfree(j->read_buffer);
+	j->read_buffer = NULL;
+	j->read_buffer_size = 0;
 	if (j->rec_mode > -1) {
 		ixj_WriteDSPCommand(0x5120, j);
 		j->rec_mode = -1;
@@ -4451,11 +4445,9 @@ static int set_play_codec(IXJ *j, int ra
 	default:
 		j->play_frame_size = 0;
 		j->play_mode = -1;
-		if (j->write_buffer) {
-			kfree(j->write_buffer);
-			j->write_buffer = NULL;
-			j->write_buffer_size = 0;
-		}
+		kfree(j->write_buffer);
+		j->write_buffer = NULL;
+		j->write_buffer_size = 0;
 		retval = 1;
 		break;
 	}
@@ -4581,11 +4573,9 @@ static void ixj_play_stop(IXJ *j)
 	if(ixjdebug & 0x0002)
 		printk("IXJ %d Stopping Play Codec %d at %ld\n", j->board, j->play_codec, jiffies);
 
-	if (j->write_buffer) {
-		kfree(j->write_buffer);
-		j->write_buffer = NULL;
-		j->write_buffer_size = 0;
-	}
+	kfree(j->write_buffer);
+	j->write_buffer = NULL;
+	j->write_buffer_size = 0;
 	if (j->play_mode > -1) {
 		ixj_WriteDSPCommand(0x5221, j);	/* Stop playback and flush buffers.  8022 reference page 9-40 */
 
@@ -5810,9 +5800,7 @@ static void ixj_cpt_stop(IXJ *j)
 		ixj_play_tone(j, 0);
 		j->tone_state = j->tone_cadence_state = 0;
 		if (j->cadence_t) {
-			if (j->cadence_t->ce) {
-				kfree(j->cadence_t->ce);
-			}
+			kfree(j->cadence_t->ce);
 			kfree(j->cadence_t);
 			j->cadence_t = NULL;
 		}
@@ -7497,10 +7485,8 @@ static void cleanup(void)
 					printk(KERN_INFO "IXJ: Releasing XILINX address for /dev/phone%d\n", cnt);
 				release_region(j->XILINXbase, 4);
 			}
-			if (j->read_buffer)
-				kfree(j->read_buffer);
-			if (j->write_buffer)
-				kfree(j->write_buffer);
+			kfree(j->read_buffer);
+			kfree(j->write_buffer);
 			if (j->dev)
 				pnp_device_detach(j->dev);
 			if (ixjdebug & 0x0002)

Re: [PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[Jesper Juhl]

On Sat, 7 May 2005, Jesper Juhl wrote:

> This patch removes redundant checks for NULL pointer before kfree() in 
> drivers/telephony/
> 
Joe Perches pointed out to me that 
	kfree
followed by
	setting all structure members would be slightly better. 

Incremental patch below.


Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
---

 drivers/telephony/ixj.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

--- linux-2.6.12-rc3-mm3/drivers/telephony/ixj.c.old	2005-05-07 03:50:43.000000000 +0200
+++ linux-2.6.12-rc3-mm3/drivers/telephony/ixj.c	2005-05-07 03:53:22.000000000 +0200
@@ -3865,9 +3865,9 @@ static int set_rec_codec(IXJ *j, int rat
 		j->rec_mode = 7;
 		break;
 	default:
+		kfree(j->read_buffer);
 		j->rec_frame_size = 0;
 		j->rec_mode = -1;
-		kfree(j->read_buffer);
 		j->read_buffer = NULL;
 		j->read_buffer_size = 0;
 		retval = 1;
@@ -3987,7 +3987,7 @@ static int ixj_record_start(IXJ *j)
 
 static void ixj_record_stop(IXJ *j)
 {
-	if(ixjdebug & 0x0002)
+	if (ixjdebug & 0x0002)
 		printk("IXJ %d Stopping Record Codec %d at %ld\n", j->board, j->rec_codec, jiffies);
 
 	kfree(j->read_buffer);
@@ -4443,9 +4443,9 @@ static int set_play_codec(IXJ *j, int ra
 		j->play_mode = 5;
 		break;
 	default:
+		kfree(j->write_buffer);
 		j->play_frame_size = 0;
 		j->play_mode = -1;
-		kfree(j->write_buffer);
 		j->write_buffer = NULL;
 		j->write_buffer_size = 0;
 		retval = 1;
@@ -4570,7 +4570,7 @@ static int ixj_play_start(IXJ *j)
 
 static void ixj_play_stop(IXJ *j)
 {
-	if(ixjdebug & 0x0002)
+	if (ixjdebug & 0x0002)
 		printk("IXJ %d Stopping Play Codec %d at %ld\n", j->board, j->play_codec, jiffies);
 
 	kfree(j->write_buffer);

Re: [PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[Andrew Morton]

This patch adds behavioural changes:

-		if (j->read_buffer) {
-			kfree(j->read_buffer);
-			j->read_buffer = NULL;
-			j->read_buffer_size = 0;
-		}
+		j->read_buffer = NULL;
+		j->read_buffer_size = 0;

Now we'll zero ->read_buffer_size even if ->read_buffer was already NULL.

It's hard to believe that this could cause any problems, but please check
that.

Re: [PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[Jesper Juhl]

On Fri, 6 May 2005, Andrew Morton wrote:

> 
> This patch adds behavioural changes:
> 
> -		if (j->read_buffer) {
> -			kfree(j->read_buffer);
> -			j->read_buffer = NULL;
> -			j->read_buffer_size = 0;
> -		}
> +		j->read_buffer = NULL;
> +		j->read_buffer_size = 0;
> 
> Now we'll zero ->read_buffer_size even if ->read_buffer was already NULL.
> 
> It's hard to believe that this could cause any problems, but please check
> that.
> 
When I initially read the code I didn't see any harm that could be done by 
that, but I'll take a second more careful look and report back - I'm 
pretty sure it's safe though.
I'll do this tomorrow since I'm off to catch some sleep now.

-- 
Jesper

Re: [PATCH] kfree cleanups (remove redundant NULL checks) in drivers/telephony/ (actually ixj.c only)

[Jesper Juhl]

On Sat, 7 May 2005, Jesper Juhl wrote:

> On Fri, 6 May 2005, Andrew Morton wrote:
> 
> > 
> > This patch adds behavioural changes:
> > 
[snip]
> > Now we'll zero ->read_buffer_size even if ->read_buffer was already NULL.
> > 
> > It's hard to believe that this could cause any problems, but please check
> > that.
> > 
> When I initially read the code I didn't see any harm that could be done by 
> that, but I'll take a second more careful look and report back - I'm 
> pretty sure it's safe though.
> I'll do this tomorrow since I'm off to catch some sleep now.
> 
Ok, I've taken a second look at the code, and I don't see any places where 
read_buffer_size are used where read_buffer is NULL, so zeroing 
read_buffer_size unconditionally when kfree()'ing read_buffer should be 
quite safe.


--
Jesper