[PATCH] zd1211rw: Readd zd_addr_t cast

[PATCH] zd1211rw: Readd zd_addr_t cast

[Daniel Drake]

Robert P.J. Day's recent commit ("getting rid of all casts of k[cmz]alloc()
calls") introduced a sparse warning for zd1211rw, related to our type-checking
of addresses.

	zd_chip.c:116:15: warning: implicit cast to nocast type

This patch readds the type cast, it is correct.

Signed-off-by: Daniel Drake <dsd@gentoo.org>

Index: linux/drivers/net/wireless/zd1211rw/zd_chip.c
===================================================================
--- linux.orig/drivers/net/wireless/zd1211rw/zd_chip.c
+++ linux/drivers/net/wireless/zd1211rw/zd_chip.c
@@ -113,7 +113,7 @@ int zd_ioread32v_locked(struct zd_chip *
 
 	/* Allocate a single memory block for values and addresses. */
 	count16 = 2*count;
-	a16 = kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
+	a16 = (zd_addr_t *) kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
 		                   GFP_NOFS);
 	if (!a16) {
 		dev_dbg_f(zd_chip_dev(chip),

Re: [PATCH] zd1211rw: Readd zd_addr_t cast

[Michael Buesch]

On Saturday 10 February 2007 02:27, Daniel Drake wrote:
> Robert P.J. Day's recent commit ("getting rid of all casts of k[cmz]alloc()
> calls") introduced a sparse warning for zd1211rw, related to our type-checking
> of addresses.
> 
> 	zd_chip.c:116:15: warning: implicit cast to nocast type
> 
> This patch readds the type cast, it is correct.
> 
> Signed-off-by: Daniel Drake <dsd-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
> 
> Index: linux/drivers/net/wireless/zd1211rw/zd_chip.c
> ===================================================================
> --- linux.orig/drivers/net/wireless/zd1211rw/zd_chip.c
> +++ linux/drivers/net/wireless/zd1211rw/zd_chip.c
> @@ -113,7 +113,7 @@ int zd_ioread32v_locked(struct zd_chip *
>  
>  	/* Allocate a single memory block for values and addresses. */
>  	count16 = 2*count;
> -	a16 = kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> +	a16 = (zd_addr_t *) kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
>  		                   GFP_NOFS);

Unrelated, but I am wondering since quite some time why you pass GFP_NOFS here.
Any special reason? I think in general there is no good reason for code outside
of the VFS to use this flag.
IMHO you should pass either GFP_ATOMIC or GFP_KERNEL.
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Re: [PATCH] zd1211rw: Readd zd_addr_t cast

[Ulrich Kunitz]

On 07-02-10 07:02 Michael Buesch wrote:

> On Saturday 10 February 2007 02:27, Daniel Drake wrote:
> > Robert P.J. Day's recent commit ("getting rid of all casts of k[cmz]alloc()
> > calls") introduced a sparse warning for zd1211rw, related to our type-checking
> > of addresses.
> > 
> > 	zd_chip.c:116:15: warning: implicit cast to nocast type
> > 
> > This patch readds the type cast, it is correct.
> > 
> > Signed-off-by: Daniel Drake <dsd@gentoo.org>
> > 
> > Index: linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > ===================================================================
> > --- linux.orig/drivers/net/wireless/zd1211rw/zd_chip.c
> > +++ linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > @@ -113,7 +113,7 @@ int zd_ioread32v_locked(struct zd_chip *
> >  
> >  	/* Allocate a single memory block for values and addresses. */
> >  	count16 = 2*count;
> > -	a16 = kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> > +	a16 = (zd_addr_t *) kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> >  		                   GFP_NOFS);
> 
> Unrelated, but I am wondering since quite some time why you pass GFP_NOFS here.
> Any special reason? I think in general there is no good reason for code outside
> of the VFS to use this flag.
> IMHO you should pass either GFP_ATOMIC or GFP_KERNEL.

Michael,

you are right. The theory has been to prevent the NFS operations
while being in the kernel. But no driver in drivers/net is using
it. I will exchange it by GFP_KERNEL, this code is protected by a
mutex and is not atomic.

Ciao,

Uli

-- 
Uli Kunitz

Re: [PATCH] zd1211rw: Readd zd_addr_t cast

[Joe Perches]

On Sat, 2007-02-10 at 07:02 +0100, Michael Buesch wrote:
> On Saturday 10 February 2007 02:27, Daniel Drake wrote:
> > Robert P.J. Day's recent commit ("getting rid of all casts of k[cmz]alloc()
> > calls") introduced a sparse warning for zd1211rw, related to our type-checking
> > of addresses.
> > > 	zd_chip.c:116:15: warning: implicit cast to nocast type
> > This patch readds the type cast, it is correct.
> > Signed-off-by: Daniel Drake <dsd@gentoo.org>
> > Index: linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > ===================================================================
> > --- linux.orig/drivers/net/wireless/zd1211rw/zd_chip.c
> > +++ linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > @@ -113,7 +113,7 @@ int zd_ioread32v_locked(struct zd_chip *
> >  
> >  	/* Allocate a single memory block for values and addresses. */
> >  	count16 = 2*count;
> > -	a16 = kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> > +	a16 = (zd_addr_t *) kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> >  		                   GFP_NOFS);

I think it better to remove this __nocast instead.
This is the only use of __nocast outside of kmem in the kernel tree.

Why not just remove __nocast and use u16 instead of zd_addr_t?

If not the removal of the __nocast, would it be better to have a
void pointer there?

	tmp = kcalloc(count16, sizeof(zd_addr_t) + sizeof(u16), GFP_KERNEL);
	[]
	a16 = (zd_addr_t *)tmp;
	v16 = a16 + count16;
	[]
	kfree(tmp);

Re: [PATCH] zd1211rw: Readd zd_addr_t cast

[Ulrich Kunitz]

On 07-02-10 10:51 Joe Perches wrote:

> On Sat, 2007-02-10 at 07:02 +0100, Michael Buesch wrote:
> > On Saturday 10 February 2007 02:27, Daniel Drake wrote:
> > > Robert P.J. Day's recent commit ("getting rid of all casts of k[cmz]alloc()
> > > calls") introduced a sparse warning for zd1211rw, related to our type-checking
> > > of addresses.
> > > > 	zd_chip.c:116:15: warning: implicit cast to nocast type
> > > This patch readds the type cast, it is correct.
> > > Signed-off-by: Daniel Drake <dsd-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
> > > Index: linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > > ===================================================================
> > > --- linux.orig/drivers/net/wireless/zd1211rw/zd_chip.c
> > > +++ linux/drivers/net/wireless/zd1211rw/zd_chip.c
> > > @@ -113,7 +113,7 @@ int zd_ioread32v_locked(struct zd_chip *
> > >  
> > >  	/* Allocate a single memory block for values and addresses. */
> > >  	count16 = 2*count;
> > > -	a16 = kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> > > +	a16 = (zd_addr_t *) kmalloc(count16 * (sizeof(zd_addr_t) + sizeof(u16)),
> > >  		                   GFP_NOFS);
> 
> I think it better to remove this __nocast instead.
> This is the only use of __nocast outside of kmem in the kernel tree.
> 
> Why not just remove __nocast and use u16 instead of zd_addr_t?

Using the __nocast type sparse catches errors, when address and
value arguments are used in the wrong order for calls of the
zd_ioread* and zd_iowrite* functions. I'm a lazy guy, I like tools
do the hard work for me. 

> If not the removal of the __nocast, would it be better to have a
> void pointer there?

I don't think that an explicit cast requires the introduction of a
temporary variable.

-- 
Uli Kunitz
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