[SCSI] iscsi_tcp, libiscsi: initial AHS Support
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>
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index e1fb3d0..a9a9e86 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -78,6 +78,9 @@
#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 @@
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 @@
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_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