Re: [Qemu-devel] [PATCH 04/10] seqlock: rename write_lock/unlock to write_begin/end

["Alex Bennée" <alex.bennee@linaro.org>]

Emilio G. Cota <cota@braap.org> writes:

> It is a more appropriate name, now that the mutex embedded
> in the seqlock is gone.
>
> Signed-off-by: Emilio G. Cota <cota@braap.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  cpus.c                 | 28 ++++++++++++++--------------
>  include/qemu/seqlock.h |  4 ++--
>  2 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 7f550b9..7dad2e6 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -247,13 +247,13 @@ int64_t cpu_get_clock(void)
>  void cpu_enable_ticks(void)
>  {
>      /* Here, the really thing protected by seqlock is cpu_clock_offset. */
> -    seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_begin(&timers_state.vm_clock_seqlock);
>      if (!timers_state.cpu_ticks_enabled) {
>          timers_state.cpu_ticks_offset -= cpu_get_host_ticks();
>          timers_state.cpu_clock_offset -= get_clock();
>          timers_state.cpu_ticks_enabled = 1;
>      }
> -    seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_end(&timers_state.vm_clock_seqlock);
>  }
>
>  /* disable cpu_get_ticks() : the clock is stopped. You must not call
> @@ -263,13 +263,13 @@ void cpu_enable_ticks(void)
>  void cpu_disable_ticks(void)
>  {
>      /* Here, the really thing protected by seqlock is cpu_clock_offset. */
> -    seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_begin(&timers_state.vm_clock_seqlock);
>      if (timers_state.cpu_ticks_enabled) {
>          timers_state.cpu_ticks_offset += cpu_get_host_ticks();
>          timers_state.cpu_clock_offset = cpu_get_clock_locked();
>          timers_state.cpu_ticks_enabled = 0;
>      }
> -    seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_end(&timers_state.vm_clock_seqlock);
>  }
>
>  /* Correlation between real and virtual time is always going to be
> @@ -292,7 +292,7 @@ static void icount_adjust(void)
>          return;
>      }
>
> -    seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_begin(&timers_state.vm_clock_seqlock);
>      cur_time = cpu_get_clock_locked();
>      cur_icount = cpu_get_icount_locked();
>
> @@ -313,7 +313,7 @@ static void icount_adjust(void)
>      last_delta = delta;
>      timers_state.qemu_icount_bias = cur_icount
>                                - (timers_state.qemu_icount << icount_time_shift);
> -    seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_end(&timers_state.vm_clock_seqlock);
>  }
>
>  static void icount_adjust_rt(void *opaque)
> @@ -345,7 +345,7 @@ static void icount_warp_rt(void)
>          return;
>      }
>
> -    seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_begin(&timers_state.vm_clock_seqlock);
>      if (runstate_is_running()) {
>          int64_t clock = REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT,
>                                       cpu_get_clock_locked());
> @@ -364,7 +364,7 @@ static void icount_warp_rt(void)
>          timers_state.qemu_icount_bias += warp_delta;
>      }
>      vm_clock_warp_start = -1;
> -    seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +    seqlock_write_end(&timers_state.vm_clock_seqlock);
>
>      if (qemu_clock_expired(QEMU_CLOCK_VIRTUAL)) {
>          qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
> @@ -389,9 +389,9 @@ void qtest_clock_warp(int64_t dest)
>          int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
>          int64_t warp = qemu_soonest_timeout(dest - clock, deadline);
>
> -        seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +        seqlock_write_begin(&timers_state.vm_clock_seqlock);
>          timers_state.qemu_icount_bias += warp;
> -        seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +        seqlock_write_end(&timers_state.vm_clock_seqlock);
>
>          qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
>          timerlist_run_timers(aio_context->tlg.tl[QEMU_CLOCK_VIRTUAL]);
> @@ -458,9 +458,9 @@ void qemu_start_warp_timer(void)
>               * It is useful when we want a deterministic execution time,
>               * isolated from host latencies.
>               */
> -            seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +            seqlock_write_begin(&timers_state.vm_clock_seqlock);
>              timers_state.qemu_icount_bias += deadline;
> -            seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +            seqlock_write_end(&timers_state.vm_clock_seqlock);
>              qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
>          } else {
>              /*
> @@ -471,11 +471,11 @@ void qemu_start_warp_timer(void)
>               * you will not be sending network packets continuously instead of
>               * every 100ms.
>               */
> -            seqlock_write_lock(&timers_state.vm_clock_seqlock);
> +            seqlock_write_begin(&timers_state.vm_clock_seqlock);
>              if (vm_clock_warp_start == -1 || vm_clock_warp_start > clock) {
>                  vm_clock_warp_start = clock;
>              }
> -            seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> +            seqlock_write_end(&timers_state.vm_clock_seqlock);
>              timer_mod_anticipate(icount_warp_timer, clock + deadline);
>          }
>      } else if (deadline == 0) {
> diff --git a/include/qemu/seqlock.h b/include/qemu/seqlock.h
> index e673482..4dfc055 100644
> --- a/include/qemu/seqlock.h
> +++ b/include/qemu/seqlock.h
> @@ -28,7 +28,7 @@ static inline void seqlock_init(QemuSeqLock *sl)
>  }
>
>  /* Lock out other writers and update the count.  */
> -static inline void seqlock_write_lock(QemuSeqLock *sl)
> +static inline void seqlock_write_begin(QemuSeqLock *sl)
>  {
>      ++sl->sequence;
>
> @@ -36,7 +36,7 @@ static inline void seqlock_write_lock(QemuSeqLock *sl)
>      smp_wmb();
>  }
>
> -static inline void seqlock_write_unlock(QemuSeqLock *sl)
> +static inline void seqlock_write_end(QemuSeqLock *sl)
>  {
>      /* Write other fields before finalizing sequence.  */
>      smp_wmb();


--
Alex Bennée