/** * __sg_free_table - Free a previously mapped sg table * @table: The sg table header to use * @max_ents: The maximum number of entries per single scatterlist * @free_fn: Free function * * Description: * Free an sg table previously allocated and setup with * __sg_alloc_table(). The @max_ents value must be identical to * that previously used with __sg_alloc_table(). * **/ void __sg_free_table(struct sg_table *table, unsigned int max_ents, sg_free_fn *free_fn) { struct scatterlist *sgl, *next; if (unlikely(!table->sgl)) return; sgl = table->sgl; while (table->orig_nents && sgl) { unsigned int alloc_size = table->orig_nents; unsigned int sg_size; /* * If we have more than max_ents segments left, * then assign 'next' to the sg table after the current one. * sg_size is then one less than alloc size, since the last * element is the chain pointer. */ if (alloc_size > max_ents) { next = sg_chain_ptr(&sgl[max_ents - 1]); alloc_size = max_ents; sg_size = alloc_size - 1; } else { sg_size = alloc_size; next = NULL; } table->orig_nents -= sg_size; free_fn(sgl, alloc_size); sgl = next; } table->sgl = NULL; }
void __sg_free_table(struct sg_table *table, unsigned int max_ents, sg_free_fn *free_fn) { struct scatterlist *sgl, *next; if (unlikely(!table->sgl)) return; sgl = table->sgl; while (table->orig_nents) { unsigned int alloc_size = table->orig_nents; unsigned int sg_size; if (alloc_size > max_ents) { next = sg_chain_ptr(&sgl[max_ents - 1]); alloc_size = max_ents; sg_size = alloc_size - 1; } else { sg_size = alloc_size; next = NULL; } table->orig_nents -= sg_size; free_fn(sgl, alloc_size); sgl = next; } table->sgl = NULL; }
/** * sg_next - return the next scatterlist entry in a list * @sg: The current sg entry * * Description: * Usually the next entry will be @sg@ + 1, but if this sg element is part * of a chained scatterlist, it could jump to the start of a new * scatterlist array. * **/ struct scatterlist *sg_next(struct scatterlist *sg) { #ifdef CONFIG_DEBUG_SG BUG_ON(sg->sg_magic != SG_MAGIC); #endif if (sg_is_last(sg)) return NULL; sg++; if (unlikely(sg_is_chain(sg))) sg = sg_chain_ptr(sg); return sg; }