Since sg-read is a bidi operation, it is a gain to convert
a single sg entry into a regular read. Better do this in the
generic layer then force each caller to do so.
Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
---
drivers/scsi/osd/osd_initiator.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 0433ea6..19ddf65 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -1005,11 +1005,23 @@ int osd_req_read_sg(struct osd_request *or,
const struct osd_sg_entry *sglist, unsigned numentries)
{
u64 len;
- int ret = _add_sg_continuation_descriptor(or, sglist, numentries, &len);
+ u64 off;
+ int ret;
- if (ret)
- return ret;
- osd_req_read(or, obj, 0, bio, len);
+ if (numentries > 1) {
+ off = 0;
+ ret = _add_sg_continuation_descriptor(or, sglist, numentries,
+ &len);
+ if (ret)
+ return ret;
+ } else {
+ /* Optimize the case of single segment, read_sg is a
+ * bidi operation.
+ */
+ len = sglist->len;
+ off = sglist->offset;
+ }
+ osd_req_read(or, obj, off, bio, len);
return 0;
}
--
1.7.2.3
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
