Re: [PATCH v8 06/30] packet: Add packet_data()

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Aug 05, 2025 at 05:46:04PM +0200, Laurent Vivier wrote:
> packet_data() gets the data range from a packet descriptor from a
> given pool.
> 
> It uses iov_tail to return the packet memory.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

I assume the idea is to eventually replace packet_get() with this?

> ---
>  packet.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  packet.h |  5 +++++
>  2 files changed, 47 insertions(+)
> 
> diff --git a/packet.c b/packet.c
> index 98ded4e27aae..82adc9fd1a39 100644
> --- a/packet.c
> +++ b/packet.c
> @@ -190,6 +190,48 @@ void *packet_get_do(const struct pool *p, const size_t idx,
>  	return r;
>  }
>  
> +/**
> + * packet_data_do() - Get data range from packet descriptor from given pool
> + * @p:		Packet pool
> + * @idx:	Index of packet descriptor in pool
> + * @data:	IOV tail to store the address of the data (output)
> + * @func:	For tracing: name of calling function, NULL means no trace()
> + * @line:	For tracing: caller line of function call
> + *
> + * Return: false if packet index is invalid, true otherwise.
> + * 	   If something wrong with @data, don't return at all (assert).
> + */
> +/* cppcheck-suppress unusedFunction */
> +bool packet_data_do(const struct pool *p, size_t idx,
> +		    struct iov_tail *data,
> +		    const char *func, int line)
> +{
> +	size_t i;
> +
> +	ASSERT_WITH_MSG(p->count <= p->size,
> +			"Corrupted pool count: %zu, size: %zu, %s:%i",
> +			p->count, p->size, func, line);
> +
> +	if (idx >= p->count) {
> +		debug("packet %zu from pool size: %zu, count: %zu, "
> +		      "%s:%i", idx, p->size, p->count, func, line);
> +		return false;
> +	}
> +
> +	data->cnt = 1;
> +	data->off = 0;
> +	data->iov = &p->pkt[idx];
> +
> +	for (i = 0; i < data->cnt; i++) {
> +		ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base,
> +						    data->iov[i].iov_len,
> +						    func, line),
> +				"Corrupt packet pool, %s:%i", func, line);
> +	}
> +
> +	return true;
> +}
> +
>  /**
>   * pool_flush() - Flush a packet pool
>   * @p:		Pointer to packet pool
> diff --git a/packet.h b/packet.h
> index af40b39b5251..062afb978124 100644
> --- a/packet.h
> +++ b/packet.h
> @@ -39,6 +39,9 @@ void *packet_get_try_do(const struct pool *p, const size_t idx,
>  void *packet_get_do(const struct pool *p, const size_t idx,
>  		    size_t offset, size_t len, size_t *left,
>  		    const char *func, int line);
> +bool packet_data_do(const struct pool *p, const size_t idx,
> +		    struct iov_tail *data,
> +		    const char *func, int line);
>  bool pool_full(const struct pool *p);
>  void pool_flush(struct pool *p);
>  
> @@ -49,6 +52,8 @@ void pool_flush(struct pool *p);
>  	packet_get_try_do(p, idx, offset, len, left, __func__, __LINE__)
>  #define packet_get(p, idx, offset, len, left)				\
>  	packet_get_do(p, idx, offset, len, left, __func__, __LINE__)
> +#define packet_data(p, idx, data)					\
> +	packet_data_do(p, idx, data, __func__, __LINE__)
>  
>  #define PACKET_POOL_DECL(_name, _size, _buf)				\
>  struct _name ## _t {							\

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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