lkml.org 
[lkml]   [2007]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 9/24] make atomic_read() behave consistently on ia64
    From: Chris Snook <csnook@redhat.com>

    Purify volatile use for atomic[64]_t on ia64.

    Signed-off-by: Chris Snook <csnook@redhat.com>

    --- linux-2.6.23-rc2-orig/include/asm-ia64/atomic.h 2007-07-08 19:32:17.000000000 -0400
    +++ linux-2.6.23-rc2/include/asm-ia64/atomic.h 2007-08-09 06:53:48.000000000 -0400
    @@ -17,18 +17,18 @@
    #include <asm/intrinsics.h>
    #include <asm/system.h>

    -/*
    - * On IA-64, counter must always be volatile to ensure that that the
    - * memory accesses are ordered.
    - */
    -typedef struct { volatile __s32 counter; } atomic_t;
    -typedef struct { volatile __s64 counter; } atomic64_t;
    +typedef struct { __s32 counter; } atomic_t;
    +typedef struct { __s64 counter; } atomic64_t;

    #define ATOMIC_INIT(i) ((atomic_t) { (i) })
    #define ATOMIC64_INIT(i) ((atomic64_t) { (i) })

    -#define atomic_read(v) ((v)->counter)
    -#define atomic64_read(v) ((v)->counter)
    +/*
    + * Casting to volatile here minimizes the need for barriers,
    + * without having to declare the type itself as volatile.
    + */
    +#define atomic_read(v) (*(volatile __s32 *)&(v)->counter)
    +#define atomic64_read(v) (*(volatile __s64 *)&(v)->counter)

    #define atomic_set(v,i) (((v)->counter) = (i))
    #define atomic64_set(v,i) (((v)->counter) = (i))
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2007-08-09 15:55    [W:0.025 / U:59.868 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site