SUNRPC: use cmpxchg64() in gss_seq_send64_fetch_and_inc()

Message ID 20181002205809.2300654-1-arnd@arndb.de
State Accepted
Commit 21924765862a0871908a35cb0e53e2e1c169b888
Headers show
Series
  • SUNRPC: use cmpxchg64() in gss_seq_send64_fetch_and_inc()
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Commit Message

Arnd Bergmann Oct. 2, 2018, 8:57 p.m.
The newly introduced gss_seq_send64_fetch_and_inc() fails to build on
32-bit architectures:

net/sunrpc/auth_gss/gss_krb5_seal.c:144:14: note: in expansion of macro 'cmpxchg'
   seq_send = cmpxchg(&ctx->seq_send64, old, old + 1);
              ^~~~~~~
arch/x86/include/asm/cmpxchg.h:128:3: error: call to '__cmpxchg_wrong_size' declared with attribute error: Bad argument size for cmpxchg
   __cmpxchg_wrong_size();     \

As the message tells us, cmpxchg() cannot be used on 64-bit arguments,
that's what cmpxchg64() does.

Fixes: 571ed1fd2390 ("SUNRPC: Replace krb5_seq_lock with a lockless scheme")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 net/sunrpc/auth_gss/gss_krb5_seal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.18.0

Comments

Trond Myklebust Oct. 5, 2018, 1:36 p.m. | #1
On Tue, 2018-10-02 at 22:57 +0200, Arnd Bergmann wrote:
> The newly introduced gss_seq_send64_fetch_and_inc() fails to build on

> 32-bit architectures:

> 

> net/sunrpc/auth_gss/gss_krb5_seal.c:144:14: note: in expansion of

> macro 'cmpxchg'

>    seq_send = cmpxchg(&ctx->seq_send64, old, old + 1);

>               ^~~~~~~

> arch/x86/include/asm/cmpxchg.h:128:3: error: call to

> '__cmpxchg_wrong_size' declared with attribute error: Bad argument

> size for cmpxchg

>    __cmpxchg_wrong_size();     \

> 

> As the message tells us, cmpxchg() cannot be used on 64-bit

> arguments,

> that's what cmpxchg64() does.

> 

> Fixes: 571ed1fd2390 ("SUNRPC: Replace krb5_seq_lock with a lockless

> scheme")

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> ---

>  net/sunrpc/auth_gss/gss_krb5_seal.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c

> b/net/sunrpc/auth_gss/gss_krb5_seal.c

> index 92594681d619..5775b9805bdc 100644

> --- a/net/sunrpc/auth_gss/gss_krb5_seal.c

> +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c

> @@ -141,7 +141,7 @@ gss_seq_send64_fetch_and_inc(struct krb5_ctx

> *ctx)

>  

>  	do {

>  		old = seq_send;

> -		seq_send = cmpxchg(&ctx->seq_send64, old, old + 1);

> +		seq_send = cmpxchg64(&ctx->seq_send64, old, old + 1);

>  	} while (old != seq_send);

>  	return seq_send;

>  }


Thanks Arndt! Applied.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com

Patch

diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c
index 92594681d619..5775b9805bdc 100644
--- a/net/sunrpc/auth_gss/gss_krb5_seal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_seal.c
@@ -141,7 +141,7 @@  gss_seq_send64_fetch_and_inc(struct krb5_ctx *ctx)
 
 	do {
 		old = seq_send;
-		seq_send = cmpxchg(&ctx->seq_send64, old, old + 1);
+		seq_send = cmpxchg64(&ctx->seq_send64, old, old + 1);
 	} while (old != seq_send);
 	return seq_send;
 }