2007-02-10 01:49:34

by Daniel Drake

[permalink] [raw]
Subject: [PATCH] zd1211rw: Readd zd_addr_t cast

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 <[email protected]>

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),


2007-02-10 06:02:37

by Michael Büsch

[permalink] [raw]
Subject: Re: [PATCH] zd1211rw: Readd zd_addr_t cast

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 <[email protected]>
>
> 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.

2007-02-10 19:56:53

by Ulrich Kunitz

[permalink] [raw]
Subject: Re: [PATCH] zd1211rw: Readd zd_addr_t cast

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 <[email protected]>
> > > 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

2007-02-10 19:22:31

by Joe Perches

[permalink] [raw]
Subject: Re: [PATCH] zd1211rw: Readd zd_addr_t cast

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 <[email protected]>
> > 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);


2007-02-10 07:59:28

by Ulrich Kunitz

[permalink] [raw]
Subject: Re: [PATCH] zd1211rw: Readd zd_addr_t cast

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 <[email protected]>
> >
> > 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