[openib-general] Re: uverbs events

[ardavis]

Roland Dreier wrote:

>OK, I think I understand the problem.  The old code violates the
>assumptions that gcc makes with -fstrict-aliasing (which is one of the
>optimizations turned on by -O2).  Can you back out the patch to cq.c I
>sent and try this patch instead?
>
>Thanks,
>  Roland
>
>Index: src/doorbell.h
>===================================================================
>--- src/doorbell.h	(revision 2156)
>+++ src/doorbell.h	(working copy)
>@@ -69,14 +69,22 @@ static inline void mthca_write_db_rec(ui
> 
> #elif SIZEOF_LONG == 8
> 
>+#if __BYTE_ORDER == __LITTLE_ENDIAN
>+#  define MTHCA_PAIR_TO_64(val) ((uint64_t) val[1] << 32 | val[0])
>+#elif __BYTE_ORDER == __BIG_ENDIAN
>+#  define MTHCA_PAIR_TO_64(val) ((uint64_t) val[0] << 32 | val[1])
>+#else
>+#  error __BYTE_ORDER not defined
>+#endif
>+
> static inline void mthca_write64(uint32_t val[2], struct mthca_context *ctx, int offset)
> {
>-	*(volatile uint64_t *) (ctx->uar + offset) = *(uint64_t *) val;
>+	*(volatile uint64_t *) (ctx->uar + offset) = MTHCA_PAIR_TO_64(val);
> }
> 
> static inline void mthca_write_db_rec(uint32_t val[2], uint32_t *db)
> {
>-	*(volatile uint64_t *) db = *(uint64_t *) val;
>+	*(volatile uint64_t *) db = MTHCA_PAIR_TO_64(val);
> }
> 
> #else
>
>  
>
Done. Works fine.