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[SCSI] iscsi_tcp, libiscsi: initial AHS Support

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at libiscsi generic code
  - currently code assumes a storage space of pdu header is allocated
    at llds ctask and is pointed to by iscsi_cmd_task->hdr. Here I add
    a hdr_max field pertaining to that storage, and an hdr_len that
    accumulates the current use of the pdu-header.

  - Add an iscsi_next_hdr() inline which returns the next free space
    to write new Header at. Also iscsi_next_hdr() is used to retrieve
    the address at which to write the header-digest.

  - Add iscsi_add_hdr(length). What the user do is calls iscsi_next_hdr()
    for address of the new header, than calls iscsi_add_hdr(length) with
    the size of the new header. iscsi_add_hdr() will check if space is
    available and update to the new size. length must be padded according
    to standard.

  - Add 2 padding inline helpers thanks to Olaf. Current patch does not
    use them but Following patches will.
    Also moved definition of ISCSI_PAD_LEN to iscsi_proto.h which had
    PAD_WORD_LEN that was never used anywhere.

  - Let iscsi_prep_scsi_cmd_pdu() signal an Error return since now  it is
    possible that it will fail.

  - I was tired of yet again writing a "this is a digest" comment next to
    sizeof(__u32) so I defined a new ISCSI_DIGEST_SIZE. Now I don't need
    any comments. Changed all places that used sizeof(__u32) or "4" in
    connection to a digest.

  iscsi_tcp specific code
  - At struct iscsi_tcp_cmd_task allocate maximum space allowed in
    standard for all headers following the iscsi_cmd header. and mark
    it so in iscsi_tcp_session_create()
  - At iscsi_send_cmd_hdr() retrieve the correct headers size and
    write header digest at iscsi_next_hdr().

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Boaz Harrosh
2007-12-13 12:43:23 -06:00
committed by James Bottomley
parent 7207fea452
commit 004d6530f8
5 changed files with 94 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
include/scsi/iscsi_proto.h
View File

@@ -27,7 +27,7 @@
#define ISCSI_LISTEN_PORT 3260
/* Padding word length */
#define PAD_WORD_LEN 4
#define ISCSI_PAD_LEN 4
/*
* useful common(control and data pathes) macro
@@ -147,6 +147,14 @@ struct iscsi_rlength_ahdr {
__be32 read_length;
};
/* Extended CDB AHS */
struct iscsi_ecdb_ahdr {
__be16 ahslength; /* CDB length - 15, including reserved byte */
uint8_t ahstype;
uint8_t reserved;
uint8_t ecdb[260 - 16]; /* 4-byte aligned extended CDB spillover */
};
/* SCSI Response Header */
struct iscsi_cmd_rsp {
uint8_t opcode;

33
include/scsi/libiscsi.h
View File

@@ -78,6 +78,9 @@ enum {
#define ISCSI_ADDRESS_BUF_LEN 64
enum {
/* this is the maximum possible storage for AHSs */
ISCSI_MAX_AHS_SIZE = sizeof(struct iscsi_ecdb_ahdr) +
sizeof(struct iscsi_rlength_ahdr),
ISCSI_DIGEST_SIZE = sizeof(__u32),
};
@@ -102,10 +105,13 @@ enum {
struct iscsi_cmd_task {
/*
* Becuae LLDs allocate their hdr differently, this is a pointer to
* that storage. It must be setup at session creation time.
* Because LLDs allocate their hdr differently, this is a pointer
* and length to that storage. It must be setup at session
* creation time.
*/
struct iscsi_cmd *hdr;
unsigned short hdr_max;
unsigned short hdr_len; /* accumulated size of hdr used */
int itt; /* this ITT */
uint32_t unsol_datasn;
@@ -124,6 +130,11 @@ struct iscsi_cmd_task {
void *dd_data; /* driver/transport data */
};
static inline void* iscsi_next_hdr(struct iscsi_cmd_task *ctask)
{
return (void*)ctask->hdr + ctask->hdr_len;
}
struct iscsi_conn {
struct iscsi_cls_conn *cls_conn; /* ptr to class connection */
void *dd_data; /* iscsi_transport data */
@@ -342,4 +353,22 @@ extern void iscsi_requeue_ctask(struct iscsi_cmd_task *ctask);
extern void iscsi_pool_free(struct iscsi_queue *, void **);
extern int iscsi_pool_init(struct iscsi_queue *, int, void ***, int);
/*
* inline functions to deal with padding.
*/
static inline unsigned int
iscsi_padded(unsigned int len)
{
return (len + ISCSI_PAD_LEN - 1) & ~(ISCSI_PAD_LEN - 1);
}
static inline unsigned int
iscsi_padding(unsigned int len)
{
len &= (ISCSI_PAD_LEN - 1);
if (len)
len = ISCSI_PAD_LEN - len;
return len;
}
#endif