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staging: comedi: serial2002: quiet NULL pointer sparse noise

PATCH In review H Hartley Sweeten 3 participants 5 messages Jun 8, 2012 Staging

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H Hartley Sweeten

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#0 lore raw

PATCH 1/1 staging: comedi: serial2002: quiet NULL pointer sparse noise

Quiet a number of sparse warnings in this file:

warning: Using plain integer as NULL pointer

Signed-off-by H Hartley Sweeten <[email protected]>
Cc Ian Abbott <[email protected]>
Cc Mori Hess <[email protected]>
Cc Greg Kroah-Hartman <[email protected]>

---

drivers/staging/comedi/drivers/serial2002.c +6 -6
index 9200310..c25808c 100644
@@ -643,7 +643,7 @@ err_alloc_configs:
 
 		if (result) {
 			if (devpriv->tty) {
-				filp_close(devpriv->tty, 0);
+				filp_close(devpriv->tty, NULL);
 				devpriv->tty = NULL;
 			}
 		}

@@ -653,8 +653,8 @@ err_alloc_configs:
 
 static void serial_2002_close(struct comedi_device *dev)
 {
-	if (!IS_ERR(devpriv->tty) && (devpriv->tty != 0))
-		filp_close(devpriv->tty, 0);
+	if (!IS_ERR(devpriv->tty) && devpriv->tty)
+		filp_close(devpriv->tty, NULL);
 }
 
 static int serial2002_di_rinsn(struct comedi_device *dev,

@@ -819,7 +819,7 @@ static int serial2002_attach(struct comedi_device *dev,
 	s->subdev_flags = SDF_READABLE | SDF_GROUND;
 	s->n_chan = 0;
 	s->maxdata = 1;
-	s->range_table = 0;
+	s->range_table = NULL;
 	s->insn_read = &serial2002_ai_rinsn;
 
 	/* analog output subdevice */

@@ -828,7 +828,7 @@ static int serial2002_attach(struct comedi_device *dev,
 	s->subdev_flags = SDF_WRITEABLE;
 	s->n_chan = 0;
 	s->maxdata = 1;
-	s->range_table = 0;
+	s->range_table = NULL;
 	s->insn_write = &serial2002_ao_winsn;
 	s->insn_read = &serial2002_ao_rinsn;
 

@@ -838,7 +838,7 @@ static int serial2002_attach(struct comedi_device *dev,
 	s->subdev_flags = SDF_READABLE | SDF_LSAMPL;
 	s->n_chan = 0;
 	s->maxdata = 1;
-	s->range_table = 0;
+	s->range_table = NULL;
 	s->insn_read = &serial2002_ei_rinsn;
 
 	return 1;
#1 lore raw
Quoted 3 lines · H Hartley Sweeten

Quiet a number of sparse warnings in this file:

warning: Using plain integer as NULL pointer

I wonder why sparse warns about that for a literal, unadorned 0? I suppose NULL is more explicit, but a plain 0 means the same as NULL in a pointer context (unlike a zero from some random expression).

Signature · 2 lines
-=( Ian Abbott @ MEV Ltd.    E-mail: <[email protected]>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-
#2 lore raw
Quoted 9 lines · Ian Abbott
Quoted 3 lines · H Hartley Sweeten

Quiet a number of sparse warnings in this file:

warning: Using plain integer as NULL pointer

I wonder why sparse warns about that for a literal, unadorned 0? I suppose NULL is more explicit, but a plain 0 means the same as NULL in a pointer context (unlike a zero from some random expression).

http://lwn.net/Articles/93574/

regards,
dan carpenter

#3 lore raw
Quoted 11 lines · Dan Carpenter
Quoted 8 lines · Ian Abbott
Quoted 3 lines · H Hartley Sweeten

Quiet a number of sparse warnings in this file:

warning: Using plain integer as NULL pointer

I wonder why sparse warns about that for a literal, unadorned 0? I suppose NULL is more explicit, but a plain 0 means the same as NULL in a pointer context (unlike a zero from some random expression).

http://lwn.net/Articles/93574/

Thanks for the link. I understand the intent to make null pointer constants easier to recognize. Still, the text of the sparse warning message "Using plain integer as NULL pointer" is technically incorrect since 0 is not an integer (plain or otherwise) in a pointer context, it's a null pointer constant.

I wonder if it also issues that warning for a struct initializer such as {0} where the first member of the struct is a pointer, or would it expect you to use {NULL} which is more confusing when the struct contains a mixture of pointer and non-pointer members?

Signature · 2 lines
-=( Ian Abbott @ MEV Ltd.    E-mail: <[email protected]>             )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587              )=-
#4 lore raw
Quoted 5 lines · Ian Abbott

I wonder if it also issues that warning for a struct initializer such as {0} where the first member of the struct is a pointer, or would it expect you to use {NULL} which is more confusing when the struct contains a mixture of pointer and non-pointer members?

It does warn about that. The fix is to just say:

	struct foo bar = {};

regards,
dan carpenter