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authorLogan Gunthorpe <logang@deltatee.com>2019-05-23 16:30:53 -0600
committerJon Mason <jdmason@kudzu.us>2019-06-13 08:59:47 -0400
commit246a42c51bc5dd247629f86c87d5e1b7628343c4 (patch)
tree92be49c08271bb83b9f5fc653192dc131b8f8301
parentfcdf8e95fa3b97097bd4e200f0ee04df85b04d99 (diff)
NTB: Introduce helper functions to calculate logical port number
This patch introduces the "Logical Port Number" which is similar to the "Port Number" in that it enumerates the ports in the system. The original (or Physical) "Port Number" can be any number used by the hardware to uniquely identify a port in the system. The "Logical Port Number" enumerates all ports in the system from 0 to the number of ports minus one. For example a system with 5 ports might have the following port numbers which would be enumerated thusly: Port Number: 1 2 5 7 116 Logical Port Number: 0 1 2 3 4 The logical port number is useful when calculating which resources to use for which peers. So we thus define two helper functions: ntb_logical_port_number() and ntb_peer_logical_port_number() which provide the "Logical Port Number" for the local port and any peer respectively. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Allen Hubbe <allenbh@gmail.com> Cc: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
-rw-r--r--include/linux/ntb.h53
1 files changed, 52 insertions, 1 deletions
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 604abc883741..2fadd0352683 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -616,7 +616,6 @@ static inline int ntb_port_number(struct ntb_dev *ntb)
return ntb->ops->port_number(ntb);
}
-
/**
* ntb_peer_port_count() - get the number of peer device ports
* @ntb: NTB device context.
@@ -654,6 +653,58 @@ static inline int ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
}
/**
+ * ntb_logical_port_number() - get the logical port number of the local port
+ * @ntb: NTB device context.
+ *
+ * The Logical Port Number is defined to be a unique number for each
+ * port starting from zero through to the number of ports minus one.
+ * This is in contrast to the Port Number where each port can be assigned
+ * any unique physical number by the hardware.
+ *
+ * The logical port number is useful for calculating the resource indexes
+ * used by peers.
+ *
+ * Return: the logical port number or negative value indicating an error
+ */
+static inline int ntb_logical_port_number(struct ntb_dev *ntb)
+{
+ int lport = ntb_port_number(ntb);
+ int pidx;
+
+ if (lport < 0)
+ return lport;
+
+ for (pidx = 0; pidx < ntb_peer_port_count(ntb); pidx++)
+ if (lport <= ntb_peer_port_number(ntb, pidx))
+ return pidx;
+
+ return pidx;
+}
+
+/**
+ * ntb_peer_logical_port_number() - get the logical peer port by given index
+ * @ntb: NTB device context.
+ * @pidx: Peer port index.
+ *
+ * The Logical Port Number is defined to be a unique number for each
+ * port starting from zero through to the number of ports minus one.
+ * This is in contrast to the Port Number where each port can be assigned
+ * any unique physical number by the hardware.
+ *
+ * The logical port number is useful for calculating the resource indexes
+ * used by peers.
+ *
+ * Return: the peer's logical port number or negative value indicating an error
+ */
+static inline int ntb_peer_logical_port_number(struct ntb_dev *ntb, int pidx)
+{
+ if (ntb_peer_port_number(ntb, pidx) < ntb_port_number(ntb))
+ return pidx;
+ else
+ return pidx + 1;
+}
+
+/**
* ntb_peer_port_idx() - get the peer device port index by given port number
* @ntb: NTB device context.
* @port: Peer port number.