[SCSI] libosd: write/read_sg_kern API

[pandora-kernel.git] / drivers / scsi / osd / osd_initiator.c

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index f5b5735..0433ea6 100644 (file)
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -1015,6 +1015,77 @@ int osd_req_read_sg(struct osd_request *or,
 }
 EXPORT_SYMBOL(osd_req_read_sg);
 
+/* SG-list write/read Kern API
+ *
+ * osd_req_{write,read}_sg_kern takes an array of @buff pointers and an array
+ * of sg_entries. @numentries indicates how many pointers and sg_entries there
+ * are.  By requiring an array of buff pointers. This allows a caller to do a
+ * single write/read and scatter into multiple buffers.
+ * NOTE: Each buffer + len should not cross a page boundary.
+ */
+static struct bio *_create_sg_bios(struct osd_request *or,
+       void **buff, const struct osd_sg_entry *sglist, unsigned numentries)
+{
+       struct request_queue *q = osd_request_queue(or->osd_dev);
+       struct bio *bio;
+       unsigned i;
+
+       bio = bio_kmalloc(GFP_KERNEL, numentries);
+       if (unlikely(!bio)) {
+               OSD_DEBUG("Faild to allocate BIO size=%u\n", numentries);
+               return ERR_PTR(-ENOMEM);
+       }
+
+       for (i = 0; i < numentries; i++) {
+               unsigned offset = offset_in_page(buff[i]);
+               struct page *page = virt_to_page(buff[i]);
+               unsigned len = sglist[i].len;
+               unsigned added_len;
+
+               BUG_ON(offset + len > PAGE_SIZE);
+               added_len = bio_add_pc_page(q, bio, page, len, offset);
+               if (unlikely(len != added_len)) {
+                       OSD_DEBUG("bio_add_pc_page len(%d) != added_len(%d)\n",
+                                 len, added_len);
+                       bio_put(bio);
+                       return ERR_PTR(-ENOMEM);
+               }
+       }
+
+       return bio;
+}
+
+int osd_req_write_sg_kern(struct osd_request *or,
+       const struct osd_obj_id *obj, void **buff,
+       const struct osd_sg_entry *sglist, unsigned numentries)
+{
+       struct bio *bio = _create_sg_bios(or, buff, sglist, numentries);
+       if (IS_ERR(bio))
+               return PTR_ERR(bio);
+
+       bio->bi_rw |= REQ_WRITE;
+       osd_req_write_sg(or, obj, bio, sglist, numentries);
+
+       return 0;
+}
+EXPORT_SYMBOL(osd_req_write_sg_kern);
+
+int osd_req_read_sg_kern(struct osd_request *or,
+       const struct osd_obj_id *obj, void **buff,
+       const struct osd_sg_entry *sglist, unsigned numentries)
+{
+       struct bio *bio = _create_sg_bios(or, buff, sglist, numentries);
+       if (IS_ERR(bio))
+               return PTR_ERR(bio);
+
+       osd_req_read_sg(or, obj, bio, sglist, numentries);
+
+       return 0;
+}
+EXPORT_SYMBOL(osd_req_read_sg_kern);
+
+
+
 void osd_req_get_attributes(struct osd_request *or,
        const struct osd_obj_id *obj)
 {