-
Boaz Harrosh authored
This patch adds the Scatter-Gather (sg) API to libosd. Scatter-gather enables a write/read of multiple none-contiguous areas of an object, in a single call. The extents may overlap and/or be in any order. The Scatter-Gather list is sent to the target in what is called a "cdb continuation segment". This is yet another possible segment in the osd-out-buffer. It is unlike all other segments in that it sits before the actual "data" segment (which until now was always first), and that it is signed by itself and not part of the data buffer. This is because the cdb-continuation-segment is considered a spill-over of the CDB data, and is therefor signed under OSD_SEC_CAPKEY and higher. TODO: A new osd_finalize_request_ex version should be supplied so the @caps received on the network also contains a size parameter and can be spilled over into the "cdb continuation segment". Thanks to John Chandy <john.chandy@uconn.edu> for the original code, and investigations. And the implementation of SG support in the osd-target. Original-coded-by:
John Chandy <john.chandy@uconn.edu> Signed-off-by:
Boaz Harrosh <bharrosh@panasas.com> Signed-off-by:
James Bottomley <James.Bottomley@suse.de>
e96e72c4