Re: [Qemu-devel] [PATCH] exec.c: Use tb1->phys_hash_next directly in tb_remove

[Peter Maydell]

On 20 November 2012 12:30, 陳韋任 (Wei-Ren Chen) <address@hidden> wrote:
>   When tb_remove was first commited at fd6ce8f6, there were three different
> calls pass different names to offsetof. In current codebase, the other two
> calls are replaced with tb_page_remove. There is no need to have a general
> tb_remove. Omit passing the third parameter and using tb1->phys_hash_next
> directly.

I like this, it makes the function less confusing to remove this
now-unneeded generality.

> Signed-off-by: Chen Wei-Ren <address@hidden>
> ---
>  exec.c |   10 ++++------
>  1 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 8435de0..e54fce2 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -863,17 +863,16 @@ static void tb_page_check(void)
>  #endif
>
>  /* invalidate one TB */

This comment is now a bit out of date (and in fact it has been for
some time) and should probably be deleted. (The function that really
needs a comment is the top level tb_phys_invalidate(), rather than
the helpers tb_hash_remove/tb_page_remove/tb_jmp_remove.)

> -static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb,
> -                             int next_offset)
> +static inline void tb_hash_remove(TranslationBlock **ptb, TranslationBlock 
> *tb)
>  {
>      TranslationBlock *tb1;
>      for(;;) {
>          tb1 = *ptb;
>          if (tb1 == tb) {
> -            *ptb = *(TranslationBlock **)((char *)tb1 + next_offset);
> +            *ptb = tb1->phys_hash_next;
>              break;
>          }
> -        ptb = (TranslationBlock **)((char *)tb1 + next_offset);
> +        ptb = &(tb1->phys_hash_next);

You don't need these brackets.

>      }
>  }
>
> @@ -940,8 +939,7 @@ void tb_phys_invalidate(TranslationBlock *tb, 
> tb_page_addr_t page_addr)
>      /* remove the TB from the hash list */
>      phys_pc = tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);
>      h = tb_phys_hash_func(phys_pc);
> -    tb_remove(&tb_phys_hash[h], tb,
> -              offsetof(TranslationBlock, phys_hash_next));
> +    tb_hash_remove(&tb_phys_hash[h], tb);
>
>      /* remove the TB from the page list */
>      if (tb->page_addr[0] != page_addr) {
> --
> 1.7.3.4


-- PMM