+/**
+ * bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
+ * @kiocb: kiocb describing the IO
+ * @nr_iovecs: number of iovecs to pre-allocate
+ * @bs: bio_set to allocate from
+ *
+ * Description:
+ * Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
+ * used to check if we should dip into the per-cpu bio_set allocation
+ * cache. The allocation uses GFP_KERNEL internally. On return, the
+ * bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
+ * MUST be done from process context, not hard/soft IRQ.
+ *
+ */
+struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
+ struct bio_set *bs)
+{
+ struct bio_alloc_cache *cache;
+ struct bio *bio;
+
+ if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE) || nr_vecs > BIO_INLINE_VECS)
+ return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
+
+ cache = per_cpu_ptr(bs->cache, get_cpu());
+ bio = bio_list_pop(&cache->free_list);
+ if (bio) {
+ cache->nr--;
+ put_cpu();
+ bio_init(bio, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs);
+ bio->bi_pool = bs;
+ bio_set_flag(bio, BIO_PERCPU_CACHE);
+ return bio;
+ }
+ put_cpu();
+ bio = bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
+ bio_set_flag(bio, BIO_PERCPU_CACHE);
+ return bio;
+}
+EXPORT_SYMBOL_GPL(bio_alloc_kiocb);
+