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authorBoaz Harrosh <bharrosh@panasas.com>2010-10-19 16:13:50 +0200
committerJames Bottomley <James.Bottomley@suse.de>2010-10-26 10:42:35 -0500
commit6dd1d8a7953cdc203c6eb694ce8eafe2dcd3e9da (patch)
treed75130fef86fd2a111a3908e7d32f4e6e3302f77
parente96e72c45a1e78e9266dd70113b851395a440ef3 (diff)
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[SCSI] libosd: write/read_sg_kern API
This is a trivial addition to the SG API that can receive kernel pointers. It is only used by the out-of-tree test module. So it's immediate need is questionable. For maintenance ease it might just get in, as it's very small. John. do you need this in the Kernel, or is it only for osd_ktest.ko? Signed-off-by: John A. Chandy <john.chandy@uconn.edu> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
-rw-r--r--drivers/scsi/osd/osd_initiator.c71
-rw-r--r--include/scsi/osd_initiator.h7
2 files changed, 78 insertions, 0 deletions
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index f5b5735f76d..0433ea6f27c 100644
--- 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)
{
diff --git a/include/scsi/osd_initiator.h b/include/scsi/osd_initiator.h
index 169a5dcda09..53a9e886612 100644
--- a/include/scsi/osd_initiator.h
+++ b/include/scsi/osd_initiator.h
@@ -455,6 +455,13 @@ int osd_req_write_sg(struct osd_request *or,
int osd_req_read_sg(struct osd_request *or,
const struct osd_obj_id *obj, struct bio *bio,
const struct osd_sg_entry *sglist, unsigned numentries);
+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);
+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);
+
/*
* Root/Partition/Collection/Object Attributes commands
*/