IB/srp: Implement SRP_CRED_REQ and SRP_AER_REQ
This patch adds support for SRP_CRED_REQ to avoid a lockup by targets
that use that mechanism to return credits to the initiator. This
prevents a lockup observed in the field where we would never add the
credits from the SRP_CRED_REQ to our current count, and would therefore
never send another command to the target.
Minimal support for SRP_AER_REQ is also added, as these messages can
also be used to convey additional credits to the initiator.
Based upon extensive debugging and code by Bart Van Assche and a bug
report by Chris Worley.
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/include/scsi/srp.h b/include/scsi/srp.h
index ad178fa..1ae84db 100644
--- a/include/scsi/srp.h
+++ b/include/scsi/srp.h
@@ -239,4 +239,42 @@
u8 data[0];
} __attribute__((packed));
+struct srp_cred_req {
+ u8 opcode;
+ u8 sol_not;
+ u8 reserved[2];
+ __be32 req_lim_delta;
+ u64 tag;
+};
+
+struct srp_cred_rsp {
+ u8 opcode;
+ u8 reserved[7];
+ u64 tag;
+};
+
+/*
+ * The SRP spec defines the fixed portion of the AER_REQ structure to be
+ * 36 bytes, so it needs to be packed to avoid having it padded to 40 bytes
+ * on 64-bit architectures.
+ */
+struct srp_aer_req {
+ u8 opcode;
+ u8 sol_not;
+ u8 reserved[2];
+ __be32 req_lim_delta;
+ u64 tag;
+ u32 reserved2;
+ __be64 lun;
+ __be32 sense_data_len;
+ u32 reserved3;
+ u8 sense_data[0];
+} __attribute__((packed));
+
+struct srp_aer_rsp {
+ u8 opcode;
+ u8 reserved[7];
+ u64 tag;
+};
+
#endif /* SCSI_SRP_H */