[XFRM]: constify 'struct xfrm_type'

[XFRM]: constify 'struct xfrm_type'

[Eric Dumazet]

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

 include/net/xfrm.h      |    8 ++++----
 net/ipv4/ah4.c          |    2 +-
 net/ipv4/esp4.c         |    2 +-
 net/ipv4/ipcomp.c       |    2 +-
 net/ipv4/xfrm4_tunnel.c |    2 +-
 net/ipv6/ah6.c          |    2 +-
 net/ipv6/esp6.c         |    2 +-
 net/ipv6/ipcomp6.c      |    2 +-
 net/ipv6/mip6.c         |    4 ++--
 net/ipv6/xfrm6_tunnel.c |    2 +-
 net/xfrm/xfrm_state.c   |   16 ++++++++--------
 11 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 5ebb9ba..02d9b1e 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -201,7 +201,7 @@ struct xfrm_state
 
 	/* Reference to data common to all the instances of this
 	 * transformer. */
-	struct xfrm_type	*type;
+	const struct xfrm_type	*type;
 	struct xfrm_mode	*inner_mode;
 	struct xfrm_mode	*outer_mode;
 
@@ -278,7 +278,7 @@ struct xfrm_state_afinfo {
 	unsigned int		proto;
 	unsigned int		eth_proto;
 	struct module		*owner;
-	struct xfrm_type	*type_map[IPPROTO_MAX];
+	const struct xfrm_type	*type_map[IPPROTO_MAX];
 	struct xfrm_mode	*mode_map[XFRM_MODE_MAX];
 	int			(*init_flags)(struct xfrm_state *x);
 	void			(*init_tempsel)(struct xfrm_state *x, struct flowi *fl,
@@ -321,8 +321,8 @@ struct xfrm_type
 	u32			(*get_mtu)(struct xfrm_state *, int size);
 };
 
-extern int xfrm_register_type(struct xfrm_type *type, unsigned short family);
-extern int xfrm_unregister_type(struct xfrm_type *type, unsigned short family);
+extern int xfrm_register_type(const struct xfrm_type *type, unsigned short family);
+extern int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family);
 
 struct xfrm_mode {
 	/*
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 3003503..4463eeb 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -216,10 +216,10 @@ static void xfrm_state_unlock_afinfo(struct xfrm_state_afinfo *afinfo)
 	write_unlock_bh(&xfrm_state_afinfo_lock);
 }
 
-int xfrm_register_type(struct xfrm_type *type, unsigned short family)
+int xfrm_register_type(const struct xfrm_type *type, unsigned short family)
 {
 	struct xfrm_state_afinfo *afinfo = xfrm_state_lock_afinfo(family);
-	struct xfrm_type **typemap;
+	const struct xfrm_type **typemap;
 	int err = 0;
 
 	if (unlikely(afinfo == NULL))
@@ -235,10 +235,10 @@ int xfrm_register_type(struct xfrm_type *type, unsigned short family)
 }
 EXPORT_SYMBOL(xfrm_register_type);
 
-int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
+int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family)
 {
 	struct xfrm_state_afinfo *afinfo = xfrm_state_lock_afinfo(family);
-	struct xfrm_type **typemap;
+	const struct xfrm_type **typemap;
 	int err = 0;
 
 	if (unlikely(afinfo == NULL))
@@ -254,11 +254,11 @@ int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
 }
 EXPORT_SYMBOL(xfrm_unregister_type);
 
-static struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
+static const struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
 {
 	struct xfrm_state_afinfo *afinfo;
-	struct xfrm_type **typemap;
-	struct xfrm_type *type;
+	const struct xfrm_type **typemap;
+	const struct xfrm_type *type;
 	int modload_attempted = 0;
 
 retry:
@@ -281,7 +281,7 @@ retry:
 	return type;
 }
 
-static void xfrm_put_type(struct xfrm_type *type)
+static void xfrm_put_type(const struct xfrm_type *type)
 {
 	module_put(type->owner);
 }
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index d76803a..9d4555e 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -300,7 +300,7 @@ static void ah_destroy(struct xfrm_state *x)
 }
 
 
-static struct xfrm_type ah_type =
+static const struct xfrm_type ah_type =
 {
 	.description	= "AH4",
 	.owner		= THIS_MODULE,
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 28ea5c7..602779d 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -448,7 +448,7 @@ error:
 	return -EINVAL;
 }
 
-static struct xfrm_type esp_type =
+static const struct xfrm_type esp_type =
 {
 	.description	= "ESP4",
 	.owner		= THIS_MODULE,
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index f4af99a..b271f87 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -434,7 +434,7 @@ error:
 	goto out;
 }
 
-static struct xfrm_type ipcomp_type = {
+static const struct xfrm_type ipcomp_type = {
 	.description	= "IPCOMP4",
 	.owner		= THIS_MODULE,
 	.proto	     	= IPPROTO_COMP,
diff --git a/net/ipv4/xfrm4_tunnel.c b/net/ipv4/xfrm4_tunnel.c
index 3268451..87f77e4 100644
--- a/net/ipv4/xfrm4_tunnel.c
+++ b/net/ipv4/xfrm4_tunnel.c
@@ -38,7 +38,7 @@ static void ipip_destroy(struct xfrm_state *x)
 {
 }
 
-static struct xfrm_type ipip_type = {
+static const struct xfrm_type ipip_type = {
 	.description	= "IPIP",
 	.owner		= THIS_MODULE,
 	.proto	     	= IPPROTO_IPIP,
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index fb0d07a..379c8e0 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -515,7 +515,7 @@ static void ah6_destroy(struct xfrm_state *x)
 	kfree(ahp);
 }
 
-static struct xfrm_type ah6_type =
+static const struct xfrm_type ah6_type =
 {
 	.description	= "AH6",
 	.owner		= THIS_MODULE,
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 5bd5292..e3fd9fe 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -395,7 +395,7 @@ error:
 	return -EINVAL;
 }
 
-static struct xfrm_type esp6_type =
+static const struct xfrm_type esp6_type =
 {
 	.description	= "ESP6",
 	.owner	     	= THIS_MODULE,
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index b276d04..c8f38e0 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -450,7 +450,7 @@ error:
 	goto out;
 }
 
-static struct xfrm_type ipcomp6_type =
+static const struct xfrm_type ipcomp6_type =
 {
 	.description	= "IPCOMP6",
 	.owner		= THIS_MODULE,
diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index 49d3966..cd8a5bd 100644
--- a/net/ipv6/mip6.c
+++ b/net/ipv6/mip6.c
@@ -330,7 +330,7 @@ static void mip6_destopt_destroy(struct xfrm_state *x)
 {
 }
 
-static struct xfrm_type mip6_destopt_type =
+static const struct xfrm_type mip6_destopt_type =
 {
 	.description	= "MIP6DESTOPT",
 	.owner		= THIS_MODULE,
@@ -462,7 +462,7 @@ static void mip6_rthdr_destroy(struct xfrm_state *x)
 {
 }
 
-static struct xfrm_type mip6_rthdr_type =
+static const struct xfrm_type mip6_rthdr_type =
 {
 	.description	= "MIP6RT",
 	.owner		= THIS_MODULE,
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index fae90ff..639fe8a 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -319,7 +319,7 @@ static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 }
 
-static struct xfrm_type xfrm6_tunnel_type = {
+static const struct xfrm_type xfrm6_tunnel_type = {
 	.description	= "IP6IP6",
 	.owner          = THIS_MODULE,
 	.proto		= IPPROTO_IPV6,

Re: [XFRM]: constify 'struct xfrm_type'

[Joe Perches]

On Thu, 2008-01-24 at 12:26 +0100, Eric Dumazet wrote:
> -	struct xfrm_type *type;
> +	const struct xfrm_type *type;

Perhaps const foo * const bar; for most or all of these
conversions?

Re: [XFRM]: constify 'struct xfrm_type'

[Eric Dumazet]

Joe Perches a écrit :
> On Thu, 2008-01-24 at 12:26 +0100, Eric Dumazet wrote:
>> -	struct xfrm_type *type;
>> +	const struct xfrm_type *type;
> 
> Perhaps const foo * const bar; for most or all of these
> conversions?
> 

Hum...

Having const data is nice because moving them from .data to .rodata,
but what would be practical gains to use a const pointer ???

Re: [XFRM]: constify 'struct xfrm_type'

[Joe Perches]

On Thu, 2008-01-24 at 19:23 +0100, Eric Dumazet wrote:
> Having const data is nice because moving them from .data to .rodata,
> but what would be practical gains to use a const pointer ???

const data is good, using pointers to const data is good.
using const pointers to const data is good.
using const pointers to data not specified as const is not so good.

Here's what you are doing now.

+static void xfrm_put_type(const struct xfrm_type *type)
[...]
+	const struct xfrm_type *type;

cheers, Joe

Re: [XFRM]: constify 'struct xfrm_type'

[Eric Dumazet]

Joe Perches a écrit :
> On Thu, 2008-01-24 at 19:23 +0100, Eric Dumazet wrote:
>> Having const data is nice because moving them from .data to .rodata,
>> but what would be practical gains to use a const pointer ???
> 
> const data is good, using pointers to const data is good.

Yes, this is what is done.

> using const pointers to const data is good.

const pointers are seldom used in linux kernel, because mostly useless.

> using const pointers to data not specified as const is not so good.

You misread the patch. I am not using const pointers at all, but const data.



> 
> Here's what you are doing now.
> 
> +static void xfrm_put_type(const struct xfrm_type *type)
> [...]
> +	const struct xfrm_type *type;
> 

Yes, this was the plan, I meant it.

I still dont understand what *you* want to do.

Doing :

int xfrm_unregister_type(const struct xfrm_type * const type, const unsigned 
short family)

instead of :

int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family)

buys nothing for the caller.

Re: [XFRM]: constify 'struct xfrm_type'

[Joe Perches]

On Thu, 2008-01-24 at 20:24 +0100, Eric Dumazet wrote:
> I still dont understand what *you* want to do.

Mark the accesses as "* const" not "const *"

Re: [XFRM]: constify 'struct xfrm_type'

[David Miller]

From: Eric Dumazet <dada1@cosmosbay.com>
Date: Thu, 24 Jan 2008 12:26:21 +0100

> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

Applied, thanks Eric.