[openib-general] [PATCH 12/18] [RFC] RDMA Core Resource Management

[Steve Wise]

ISSUES:

- this is using kfifos to manage basically a list of numbers to dish out
as QPIDs, CQIDs, STAGs.  A bitmap would be more efficient memory-wise,
but there is an issue with STAG indecies:  They are supposed to be
random.  This code doesn't handle this, but could if the kfifo list was
randomized.  A bitmap wouldn't support random allocation of stag ids...



--- old/src/linux-kernel/infiniband/hw/cxgb3/core/cxio_resource.c	1969-12-31 18:00:00.000000000 -0600
+++ new/src/linux-kernel/infiniband/hw/cxgb3/core/cxio_resource.c	2006-03-06 09:26:21.000000000 -0600
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2006 Chelsio, Inc. All rights reserved.
+ * Copyright (c) 2006 Open Grid Computing, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+/* Crude resource management */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/kfifo.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include "cxio_hal.h"
+
+static struct kfifo *rhdl_fifo;
+static spinlock_t rhdl_fifo_lock;
+
+static int cxio_init_resource_fifo(struct kfifo **fifo, spinlock_t * fifo_lock,
+				   u32 nr, u32 skip_low, u32 skip_high)
+{
+	u32 i, entry = 0;
+	spin_lock_init(fifo_lock);
+	if (!((*fifo) = kfifo_alloc(nr * sizeof(u32), GFP_KERNEL, fifo_lock)))
+		return -ENOMEM;
+	for (i = 0; i < skip_low + skip_high; i++)
+		__kfifo_put(*fifo, (unsigned char *) &entry, sizeof(u32));
+	for (i = skip_low; i < nr - skip_high; i++)
+		__kfifo_put(*fifo, (unsigned char *) &i, sizeof(u32));
+	for (i = 0; i < skip_low + skip_high; i++)
+		kfifo_get(*fifo, (unsigned char *) &entry, sizeof(u32));
+	return 0;
+}
+
+int cxio_hal_init_rhdl_resource(u32 nr_rhdl)
+{
+	return cxio_init_resource_fifo(&rhdl_fifo, &rhdl_fifo_lock, nr_rhdl, 1,
+				       0);
+}
+
+void cxio_hal_destroy_rhdl_resource(void)
+{
+	kfifo_free(rhdl_fifo);
+}
+
+/* nr_* must be power of 2 */
+int cxio_hal_init_resource(struct cxio_hal_resource **rscpp,
+			   u32 nr_tpt, u32 nr_pbl,
+			   u32 nr_rqt, u32 nr_qpid, u32 nr_cqid, u32 nr_pdid)
+{
+	int err = 0;
+	struct cxio_hal_resource *rscp;
+	if (!(rscp = kmalloc(sizeof(*rscp), GFP_KERNEL))) {
+		return -ENOMEM;
+	}
+	*rscpp = rscp;
+	if ((err =
+	     cxio_init_resource_fifo(&rscp->tpt_fifo, &rscp->tpt_fifo_lock,
+				     nr_tpt, 1, 0)))
+		goto tpt_err;
+	if ((err =
+	     cxio_init_resource_fifo(&rscp->qpid_fifo, &rscp->qpid_fifo_lock,
+				     nr_qpid, 16, 16)))
+		goto qpid_err;
+	if ((err =
+	     cxio_init_resource_fifo(&rscp->cqid_fifo, &rscp->cqid_fifo_lock,
+				     nr_cqid, 1, 0)))
+		goto cqid_err;
+	if ((err =
+	     cxio_init_resource_fifo(&rscp->pdid_fifo, &rscp->pdid_fifo_lock,
+				     nr_pdid, 1, 0)))
+		goto pdid_err;
+	return 0;
+pdid_err:
+	kfifo_free(rscp->cqid_fifo);
+cqid_err:
+	kfifo_free(rscp->qpid_fifo);
+qpid_err:
+	kfifo_free(rscp->tpt_fifo);
+tpt_err:
+	return -ENOMEM;
+}
+
+/*
+ * returns 0 if no resource available
+ */
+static inline u32 cxio_hal_get_resource(struct kfifo *fifo)
+{
+	u32 entry;
+	if (kfifo_get(fifo, (unsigned char *) &entry, sizeof(u32)))
+		return entry;
+	else
+		return 0;	/* fifo emptry */
+}
+
+static inline void cxio_hal_put_resource(struct kfifo *fifo, u32 entry)
+{
+	BUG_ON(kfifo_put(fifo, (unsigned char *) &entry, sizeof(u32)) == 0);
+}
+
+u32 cxio_hal_get_rhdl(void)
+{
+	return cxio_hal_get_resource(rhdl_fifo);
+}
+
+void cxio_hal_put_rhdl(u32 rhdl)
+{
+	cxio_hal_put_resource(rhdl_fifo, rhdl);
+}
+
+u32 cxio_hal_get_stag(struct cxio_hal_resource *rscp)
+{
+	return cxio_hal_get_resource(rscp->tpt_fifo);
+}
+
+void cxio_hal_put_stag(struct cxio_hal_resource *rscp, u32 stag)
+{
+	cxio_hal_put_resource(rscp->tpt_fifo, stag);
+}
+
+u32 cxio_hal_get_qpid(struct cxio_hal_resource *rscp)
+{
+	return cxio_hal_get_resource(rscp->qpid_fifo);
+}
+
+void cxio_hal_put_qpid(struct cxio_hal_resource *rscp, u32 qpid)
+{
+	cxio_hal_put_resource(rscp->qpid_fifo, qpid);
+}
+
+u32 cxio_hal_get_cqid(struct cxio_hal_resource *rscp)
+{
+	return cxio_hal_get_resource(rscp->cqid_fifo);
+}
+
+void cxio_hal_put_cqid(struct cxio_hal_resource *rscp, u32 cqid)
+{
+	cxio_hal_put_resource(rscp->cqid_fifo, cqid);
+}
+
+u32 cxio_hal_get_pdid(struct cxio_hal_resource *rscp)
+{
+	return cxio_hal_get_resource(rscp->pdid_fifo);
+}
+
+void cxio_hal_put_pdid(struct cxio_hal_resource *rscp, u32 pdid)
+{
+	cxio_hal_put_resource(rscp->pdid_fifo, pdid);
+}
+
+void cxio_hal_destroy_resource(struct cxio_hal_resource *rscp)
+{
+	kfifo_free(rscp->tpt_fifo);
+	kfifo_free(rscp->cqid_fifo);
+	kfifo_free(rscp->qpid_fifo);
+	kfifo_free(rscp->pdid_fifo);
+	kfree(rscp);
+}