+int _ore_get_io_state(struct ore_layout *layout,
+ struct ore_components *oc, unsigned numdevs,
+ unsigned sgs_per_dev, unsigned num_par_pages,
+ struct ore_io_state **pios)
+{
+ struct ore_io_state *ios;
+ struct page **pages;
+ struct osd_sg_entry *sgilist;
+ struct __alloc_all_io_state {
+ struct ore_io_state ios;
+ struct ore_per_dev_state per_dev[numdevs];
+ union {
+ struct osd_sg_entry sglist[sgs_per_dev * numdevs];
+ struct page *pages[num_par_pages];
+ };
+ } *_aios;
+
+ if (likely(sizeof(*_aios) <= PAGE_SIZE)) {
+ _aios = kzalloc(sizeof(*_aios), GFP_KERNEL);
+ if (unlikely(!_aios)) {
+ ORE_DBGMSG("Failed kzalloc bytes=%zd\n",
+ sizeof(*_aios));
+ *pios = NULL;
+ return -ENOMEM;
+ }
+ pages = num_par_pages ? _aios->pages : NULL;
+ sgilist = sgs_per_dev ? _aios->sglist : NULL;
+ ios = &_aios->ios;
+ } else {
+ struct __alloc_small_io_state {
+ struct ore_io_state ios;
+ struct ore_per_dev_state per_dev[numdevs];
+ } *_aio_small;
+ union __extra_part {
+ struct osd_sg_entry sglist[sgs_per_dev * numdevs];
+ struct page *pages[num_par_pages];
+ } *extra_part;
+
+ _aio_small = kzalloc(sizeof(*_aio_small), GFP_KERNEL);
+ if (unlikely(!_aio_small)) {
+ ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
+ sizeof(*_aio_small));
+ *pios = NULL;
+ return -ENOMEM;
+ }
+ extra_part = kzalloc(sizeof(*extra_part), GFP_KERNEL);
+ if (unlikely(!extra_part)) {
+ ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
+ sizeof(*extra_part));
+ kfree(_aio_small);
+ *pios = NULL;
+ return -ENOMEM;
+ }
+
+ pages = num_par_pages ? extra_part->pages : NULL;
+ sgilist = sgs_per_dev ? extra_part->sglist : NULL;
+ /* In this case the per_dev[0].sgilist holds the pointer to
+ * be freed
+ */
+ ios = &_aio_small->ios;
+ ios->extra_part_alloc = true;
+ }
+
+ if (pages) {
+ ios->parity_pages = pages;
+ ios->max_par_pages = num_par_pages;
+ }
+ if (sgilist) {
+ unsigned d;
+
+ for (d = 0; d < numdevs; ++d) {
+ ios->per_dev[d].sglist = sgilist;
+ sgilist += sgs_per_dev;
+ }
+ ios->sgs_per_dev = sgs_per_dev;
+ }
+
+ ios->layout = layout;
+ ios->oc = oc;
+ *pios = ios;
+ return 0;
+}
+
+/* Allocate an io_state for only a single group of devices
+ *
+ * If a user needs to call ore_read/write() this version must be used becase it
+ * allocates extra stuff for striping and raid.
+ * The ore might decide to only IO less then @length bytes do to alignmets
+ * and constrains as follows:
+ * - The IO cannot cross group boundary.
+ * - In raid5/6 The end of the IO must align at end of a stripe eg.
+ * (@offset + @length) % strip_size == 0. Or the complete range is within a
+ * single stripe.
+ * - Memory condition only permitted a shorter IO. (A user can use @length=~0
+ * And check the returned ios->length for max_io_size.)
+ *
+ * The caller must check returned ios->length (and/or ios->nr_pages) and
+ * re-issue these pages that fall outside of ios->length
+ */
+int ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,