From e96e72c45a1e78e9266dd70113b851395a440ef3 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Tue, 19 Oct 2010 14:22:21 +0200 Subject: [SCSI] libosd: Support for scatter gather write/read commands 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 for the original code, and investigations. And the implementation of SG support in the osd-target. Original-coded-by: John Chandy Signed-off-by: Boaz Harrosh Signed-off-by: James Bottomley --- include/scsi/osd_protocol.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'include/scsi/osd_protocol.h') diff --git a/include/scsi/osd_protocol.h b/include/scsi/osd_protocol.h index 685661283540..a6026da25f3e 100644 --- a/include/scsi/osd_protocol.h +++ b/include/scsi/osd_protocol.h @@ -631,4 +631,46 @@ static inline void osd_sec_set_caps(struct osd_capability_head *cap, put_unaligned_le16(bit_mask, &cap->permissions_bit_mask); } +/* osd2r05a sec 5.3: CDB continuation segment formats */ +enum osd_continuation_segment_format { + CDB_CONTINUATION_FORMAT_V2 = 0x01, +}; + +struct osd_continuation_segment_header { + u8 format; + u8 reserved1; + __be16 service_action; + __be32 reserved2; + u8 integrity_check[OSDv2_CRYPTO_KEYID_SIZE]; +} __packed; + +/* osd2r05a sec 5.4.1: CDB continuation descriptors */ +enum osd_continuation_descriptor_type { + NO_MORE_DESCRIPTORS = 0x0000, + SCATTER_GATHER_LIST = 0x0001, + QUERY_LIST = 0x0002, + USER_OBJECT = 0x0003, + COPY_USER_OBJECT_SOURCE = 0x0101, + EXTENSION_CAPABILITIES = 0xFFEE +}; + +struct osd_continuation_descriptor_header { + __be16 type; + u8 reserved; + u8 pad_length; + __be32 length; +} __packed; + + +/* osd2r05a sec 5.4.2: Scatter/gather list */ +struct osd_sg_list_entry { + __be64 offset; + __be64 len; +}; + +struct osd_sg_continuation_descriptor { + struct osd_continuation_descriptor_header hdr; + struct osd_sg_list_entry entries[]; +}; + #endif /* ndef __OSD_PROTOCOL_H__ */ -- cgit v1.2.1