[PATCH 1/5] hwrng: core - Use struct completion for cleanup_done

2014-12-22 Thread Herbert Xu 
There is no point in doing a manual completion for cleanup_done
when struct completion fits in perfectly.

Signed-off-by: Herbert Xu 
---

 drivers/char/hw_random/core.c |   12 +++-
 include/linux/hw_random.h |3 ++-
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 6ec4225..3dba2cf 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -60,7 +60,6 @@ static DEFINE_MUTEX(rng_mutex);
 static DEFINE_MUTEX(reading_mutex);
 static int data_avail;
 static u8 *rng_buffer, *rng_fillbuf;
-static DECLARE_WAIT_QUEUE_HEAD(rng_done);
 static unsigned short current_quality;
 static unsigned short default_quality; /* = 0; default to "off" */
 
@@ -100,10 +99,7 @@ static inline void cleanup_rng(struct kref *kref)
if (rng->cleanup)
rng->cleanup(rng);
 
-   /* cleanup_done should be updated after cleanup finishes */
-   smp_wmb();
-   rng->cleanup_done = true;
-   wake_up_all(&rng_done);
+   complete(&rng->cleanup_done);
 }
 
 static void set_current_rng(struct hwrng *rng)
@@ -498,7 +494,7 @@ int hwrng_register(struct hwrng *rng)
add_early_randomness(rng);
}
 
-   rng->cleanup_done = false;
+   init_completion(&rng->cleanup_done);
 
 out_unlock:
mutex_unlock(&rng_mutex);
@@ -532,9 +528,7 @@ void hwrng_unregister(struct hwrng *rng)
} else
mutex_unlock(&rng_mutex);
 
-   /* Just in case rng is reading right now, wait. */
-   wait_event(rng_done, rng->cleanup_done &&
-  atomic_read(&rng->ref.refcount) == 0);
+   wait_for_completion(&rng->cleanup_done);
 }
 EXPORT_SYMBOL_GPL(hwrng_unregister);
 
diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
index 7832e50..eb7b414 100644
--- a/include/linux/hw_random.h
+++ b/include/linux/hw_random.h
@@ -12,6 +12,7 @@
 #ifndef LINUX_HWRANDOM_H_
 #define LINUX_HWRANDOM_H_
 
+#include 
 #include 
 #include 
 #include 
@@ -46,7 +47,7 @@ struct hwrng {
/* internal. */
struct list_head list;
struct kref ref;
-   bool cleanup_done;
+   struct completion cleanup_done;
 };
 
 /** Register a new Hardware Random Number Generator driver. */
--
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Re: [PATCH 1/5] hwrng: core - Use struct completion for cleanup_done

2014-12-25 Thread Rusty Russell 
Herbert Xu  writes:
> There is no point in doing a manual completion for cleanup_done
> when struct completion fits in perfectly.
>
> Signed-off-by: Herbert Xu 

Indeed.

Acked-by: Rusty Russell 

Thanks,
Rusty.

> ---
>
>  drivers/char/hw_random/core.c |   12 +++-
>  include/linux/hw_random.h |3 ++-
>  2 files changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index 6ec4225..3dba2cf 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -60,7 +60,6 @@ static DEFINE_MUTEX(rng_mutex);
>  static DEFINE_MUTEX(reading_mutex);
>  static int data_avail;
>  static u8 *rng_buffer, *rng_fillbuf;
> -static DECLARE_WAIT_QUEUE_HEAD(rng_done);
>  static unsigned short current_quality;
>  static unsigned short default_quality; /* = 0; default to "off" */
>  
> @@ -100,10 +99,7 @@ static inline void cleanup_rng(struct kref *kref)
>   if (rng->cleanup)
>   rng->cleanup(rng);
>  
> - /* cleanup_done should be updated after cleanup finishes */
> - smp_wmb();
> - rng->cleanup_done = true;
> - wake_up_all(&rng_done);
> + complete(&rng->cleanup_done);
>  }
>  
>  static void set_current_rng(struct hwrng *rng)
> @@ -498,7 +494,7 @@ int hwrng_register(struct hwrng *rng)
>   add_early_randomness(rng);
>   }
>  
> - rng->cleanup_done = false;
> + init_completion(&rng->cleanup_done);
>  
>  out_unlock:
>   mutex_unlock(&rng_mutex);
> @@ -532,9 +528,7 @@ void hwrng_unregister(struct hwrng *rng)
>   } else
>   mutex_unlock(&rng_mutex);
>  
> - /* Just in case rng is reading right now, wait. */
> - wait_event(rng_done, rng->cleanup_done &&
> -atomic_read(&rng->ref.refcount) == 0);
> + wait_for_completion(&rng->cleanup_done);
>  }
>  EXPORT_SYMBOL_GPL(hwrng_unregister);
>  
> diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
> index 7832e50..eb7b414 100644
> --- a/include/linux/hw_random.h
> +++ b/include/linux/hw_random.h
> @@ -12,6 +12,7 @@
>  #ifndef LINUX_HWRANDOM_H_
>  #define LINUX_HWRANDOM_H_
>  
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -46,7 +47,7 @@ struct hwrng {
>   /* internal. */
>   struct list_head list;
>   struct kref ref;
> - bool cleanup_done;
> + struct completion cleanup_done;
>  };
>  
>  /** Register a new Hardware Random Number Generator driver. */
--
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