On (20/07/09 15:29), John Ogness wrote:
[..]
> +/*
> + * A data block: mapped directly to the beginning of the data block area
> + * specified as a logical position within the data ring.
> + *
> + * @id: the ID of the associated descriptor
> + * @data: the writer data
> + *
> + * Note that the size of a data block is only known by its associated
> + * descriptor.
> + */
> +struct prb_data_block {
> + unsigned long id;
> + char data[0];
> +};
A nit: I think someone will send "Replace zero-length arrays with
flexible array member" soon enough:
- char data[0];
+ char data[];
[..]
> +/*
> + * Sanity checker for reserve size. The ringbuffer code assumes that a data
> + * block does not exceed the maximum possible size that could fit within the
> + * ringbuffer. This function provides that basic size check so that the
> + * assumption is safe.
> + *
> + * Writers are also not allowed to write 0-sized (data-less) records. Such
> + * records are used only internally by the ringbuffer.
> + */
> +static bool data_check_size(struct prb_data_ring *data_ring, unsigned int size)
> +{
> + struct prb_data_block *db = NULL;
> +
> + /*
> + * Writers are not allowed to write data-less records. Such records
> + * are used only internally by the ringbuffer to denote records where
> + * their data failed to allocate or have been lost.
> + */
A nit: The same data-less records comment is some 5 lines earlier. But OK.
> + if (size == 0)
> + return false;
[..]
> +void prb_init(struct printk_ringbuffer *rb,
> + char *text_buf, unsigned int textbits,
> + char *dict_buf, unsigned int dictbits,
> + struct prb_desc *descs, unsigned int descbits)
> +{
> + memset(descs, 0, _DESCS_COUNT(descbits) * sizeof(descs[0]));
> +
> + rb->desc_ring.count_bits = descbits;
> + rb->desc_ring.descs = descs;
> + atomic_long_set(&rb->desc_ring.head_id, DESC0_ID(descbits));
> + atomic_long_set(&rb->desc_ring.tail_id, DESC0_ID(descbits));
> +
> + rb->text_data_ring.size_bits = textbits;
> + rb->text_data_ring.data = text_buf;
> + atomic_long_set(&rb->text_data_ring.head_lpos, BLK0_LPOS(textbits));
> + atomic_long_set(&rb->text_data_ring.tail_lpos, BLK0_LPOS(textbits));
> +
> + rb->dict_data_ring.size_bits = dictbits;
> + rb->dict_data_ring.data = dict_buf;
> + atomic_long_set(&rb->dict_data_ring.head_lpos, BLK0_LPOS(dictbits));
> + atomic_long_set(&rb->dict_data_ring.tail_lpos, BLK0_LPOS(dictbits));
> +
Just a side note: some people want !CONFIG_PRINTK builds. I wonder
how many people will want !CONFIG_PRINTK_DICT. The core logbuf/dict
logbuf split is really cool.
-ss
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