Re: [dpdk-dev] [PATCH v3] ring: add function to free a ring

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Oct 02, 2015 at 03:01:25PM +0100, Pablo de Lara wrote:
> From: "Pablo de Lara" <pablo.de.lara.guarch@intel.com>
> 
> When creating a ring, a memzone is created to allocate it in memory,
> but the ring could not be freed, as memzones could not be.
> 
> Since memzones can be freed now, then rings can be as well,
> taking into account if they were initialized using pre-allocated memory
> (in which case, memory should be freed externally) or using rte_memzone_reserve
> (with rte_ring_create), freeing the memory with rte_memzone_free.
> 
> Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
> ---
> Changes in v3:
>  - Simplify patch using stored memzone address in ring structure
>  - Change copyright date

I think you need to call out that this patch depends upon
http://dpdk.org/dev/patchwork/patch/7308/

> 
> Changes in v2:
>  - Include note in release notes
>  - Add error log when ring cannot be freed
> 
> This patch depends on patch "rte_ring: store memzone pointer inside ring"
> 
>  doc/guides/rel_notes/release_2_2.rst |  4 +++
>  lib/librte_ring/rte_ring.c           | 47 +++++++++++++++++++++++++++++++++++-
>  lib/librte_ring/rte_ring.h           |  7 ++++++
>  lib/librte_ring/rte_ring_version.map |  7 ++++++
>  4 files changed, 64 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/guides/rel_notes/release_2_2.rst b/doc/guides/rel_notes/release_2_2.rst
> index 5687676..24937ac 100644
> --- a/doc/guides/rel_notes/release_2_2.rst
> +++ b/doc/guides/rel_notes/release_2_2.rst
> @@ -4,6 +4,10 @@ DPDK Release 2.2
>  New Features
>  ------------
>  
> +* **Enabled freeing of rte_ring.**
> +
> +  New function rte_ring_free() allows the user to free a ring
> +  if it was created with rte_ring_create().
>  
>  Resolved Issues
>  ---------------
> diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
> index 4e78e14..d80faf3 100644
> --- a/lib/librte_ring/rte_ring.c
> +++ b/lib/librte_ring/rte_ring.c
> @@ -1,7 +1,7 @@
>  /*-
>   *   BSD LICENSE
>   *
> - *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
> + *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
>   *   All rights reserved.
>   *
>   *   Redistribution and use in source and binary forms, with or without
> @@ -209,6 +209,51 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
>  	return r;
>  }
>  
> +/* free the ring */
> +void
> +rte_ring_free(struct rte_ring *r)
> +{
> +	struct rte_ring_list *ring_list = NULL;
> +	struct rte_tailq_entry *te;
> +
> +	if (r == NULL)
> +		return;
> +
> +	/*
> +	 * Ring was not created with rte_ring_create,
> +	 * therefore, there is no memzone to free.
> +	 */
> +	if (r->memzone == NULL) {
> +		RTE_LOG(ERR, RING, "Cannot free ring (not created with rte_ring_create()");
> +		return;
> +	}
> +
> +	if (rte_memzone_free(r->memzone) != 0) {
> +		RTE_LOG(ERR, RING, "Cannot free memory\n");
> +		return;
> +	}
> +
> +	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
> +	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
> +
> +	/* find out tailq entry */
> +	TAILQ_FOREACH(te, ring_list, next) {
> +		if (te->data == (void *) r)
> +			break;
> +	}
> +
> +	if (te == NULL) {
> +		rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
> +		return;
> +	}
> +
> +	TAILQ_REMOVE(ring_list, te, next);
> +
> +	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
> +
> +	rte_free(te);
> +}
> +
>  /*
>   * change the high water mark. If *count* is 0, water marking is
>   * disabled
> diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
> index df45f3f..fb5a626 100644
> --- a/lib/librte_ring/rte_ring.h
> +++ b/lib/librte_ring/rte_ring.h
> @@ -304,6 +304,13 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
>   */
>  struct rte_ring *rte_ring_create(const char *name, unsigned count,
>  				 int socket_id, unsigned flags);
> +/**
> + * De-allocate all memory used by the ring.
> + *
> + * @param r
> + *   Ring to free
> + */
> +void rte_ring_free(struct rte_ring *r);
>  
>  /**
>   * Change the high water mark.
> diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
> index 982fdd1..5474b98 100644
> --- a/lib/librte_ring/rte_ring_version.map
> +++ b/lib/librte_ring/rte_ring_version.map
> @@ -11,3 +11,10 @@ DPDK_2.0 {
>  
>  	local: *;
>  };
> +
> +DPDK_2.2 {
> +	global:
> +
> +	rte_ring_free;
> +
> +} DPDK_2.0;
> -- 
> 2.4.3
>