staging: lustre: move kernel_user_comm.c from libcfs to lustre

Move the kernel portion from libcfs to obdclass. This code is
only used by lustre. This is broken out of the original patch
14270. The part covered by this change is as follows:

The original code in kernel_user_comm.c is split into two parts:

  * obdclass/kernelcomm.c for the kernel part. filp_user_write() was
    moved there, and linux-fs.c deleted;
  * liblustreapi_kernelconn.c for the user part. The calls to CDEBUG
    have been removed, and calls to CERROR have been transformed to
    llapi_err_noerrno. The type lustre_kernelcomm has been removed and
    replace by struct lustre_kernelcomm.

Various names and filenames have been harmonized to *kernelcomm*.

Signed-off-by: frank zago <fzago@cray.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6245
Reviewed-on: http://review.whamcloud.com/14270
Reviewed-by: Nathan Rutman <nathan.rutman@seagate.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 250 insertions, 5 deletions

diff --git a/drivers/staging/lustre/lustre/obdclass/Makefile b/drivers/staging/lustre/lustre/obdclass/Makefile
index acc685712ce9..c404eb3864ff 100644
--- a/drivers/staging/lustre/lustre/obdclass/Makefile
+++ b/drivers/staging/lustre/lustre/obdclass/Makefile
@@ -2,8 +2,8 @@ obj-$(CONFIG_LUSTRE_FS) += obdclass.o
 
 obdclass-y := linux/linux-module.o linux/linux-obdo.o linux/linux-sysctl.o \
 	      llog.o llog_cat.o llog_obd.o llog_swab.o class_obd.o debug.o \
-	      genops.o uuid.o lprocfs_status.o \
-	      lustre_handles.o lustre_peer.o \
-	      statfs_pack.o obdo.o obd_config.o obd_mount.o \
-	      lu_object.o cl_object.o   \
-	      cl_page.o cl_lock.o cl_io.o lu_ref.o acl.o lprocfs_counters.o
+	      genops.o uuid.o lprocfs_status.o lprocfs_counters.o \
+	      lustre_handles.o lustre_peer.o statfs_pack.o \
+	      obdo.o obd_config.o obd_mount.o lu_object.o lu_ref.o \
+	      cl_object.o cl_page.o cl_lock.o cl_io.o \
+	      acl.o kernelcomm.o
diff --git a/drivers/staging/lustre/lustre/obdclass/kernelcomm.c b/drivers/staging/lustre/lustre/obdclass/kernelcomm.c
new file mode 100644
index 000000000000..3b4731aff9ed
--- /dev/null
+++ b/drivers/staging/lustre/lustre/obdclass/kernelcomm.c
@@ -0,0 +1,245 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * Author: Nathan Rutman <nathan.rutman@sun.com>
+ *
+ * Kernel <-> userspace communication routines.
+ * Using pipes for all arches.
+ */
+
+#define DEBUG_SUBSYSTEM S_CLASS
+#define D_KUC D_OTHER
+
+#include "../../include/linux/libcfs/libcfs.h"
+
+/* This is the kernel side (liblustre as well). */
+
+/**
+ * libcfs_kkuc_msg_put - send an message from kernel to userspace
+ * @param fp to send the message to
+ * @param payload Payload data.  First field of payload is always
+ *   struct kuc_hdr
+ */
+int libcfs_kkuc_msg_put(struct file *filp, void *payload)
+{
+	struct kuc_hdr *kuch = (struct kuc_hdr *)payload;
+	ssize_t count = kuch->kuc_msglen;
+	loff_t offset = 0;
+	mm_segment_t fs;
+	int rc = -ENOSYS;
+
+	if (filp == NULL || IS_ERR(filp))
+		return -EBADF;
+
+	if (kuch->kuc_magic != KUC_MAGIC) {
+		CERROR("KernelComm: bad magic %x\n", kuch->kuc_magic);
+		return -ENOSYS;
+	}
+
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	while (count > 0) {
+		rc = vfs_write(filp, (void __force __user *)payload,
+			       count, &offset);
+		if (rc < 0)
+			break;
+		count -= rc;
+		payload += rc;
+		rc = 0;
+	}
+	set_fs(fs);
+
+	if (rc < 0)
+		CWARN("message send failed (%d)\n", rc);
+	else
+		CDEBUG(D_KUC, "Sent message rc=%d, fp=%p\n", rc, filp);
+
+	return rc;
+}
+EXPORT_SYMBOL(libcfs_kkuc_msg_put);
+
+/* Broadcast groups are global across all mounted filesystems;
+ * i.e. registering for a group on 1 fs will get messages for that
+ * group from any fs */
+/** A single group registration has a uid and a file pointer */
+struct kkuc_reg {
+	struct list_head kr_chain;
+	int		 kr_uid;
+	struct file	*kr_fp;
+	void		*kr_data;
+};
+
+static struct list_head kkuc_groups[KUC_GRP_MAX+1] = {};
+/* Protect message sending against remove and adds */
+static DECLARE_RWSEM(kg_sem);
+
+/** Add a receiver to a broadcast group
+ * @param filp pipe to write into
+ * @param uid identifier for this receiver
+ * @param group group number
+ * @param data user data
+ */
+int libcfs_kkuc_group_add(struct file *filp, int uid, unsigned int group,
+			  void *data)
+{
+	struct kkuc_reg *reg;
+
+	if (group > KUC_GRP_MAX) {
+		CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
+		return -EINVAL;
+	}
+
+	/* fput in group_rem */
+	if (filp == NULL)
+		return -EBADF;
+
+	/* freed in group_rem */
+	reg = kmalloc(sizeof(*reg), 0);
+	if (reg == NULL)
+		return -ENOMEM;
+
+	reg->kr_fp = filp;
+	reg->kr_uid = uid;
+	reg->kr_data = data;
+
+	down_write(&kg_sem);
+	if (kkuc_groups[group].next == NULL)
+		INIT_LIST_HEAD(&kkuc_groups[group]);
+	list_add(&reg->kr_chain, &kkuc_groups[group]);
+	up_write(&kg_sem);
+
+	CDEBUG(D_KUC, "Added uid=%d fp=%p to group %d\n", uid, filp, group);
+
+	return 0;
+}
+EXPORT_SYMBOL(libcfs_kkuc_group_add);
+
+int libcfs_kkuc_group_rem(int uid, int group, void **pdata)
+{
+	struct kkuc_reg *reg, *next;
+
+	if (kkuc_groups[group].next == NULL)
+		return 0;
+
+	if (uid == 0) {
+		/* Broadcast a shutdown message */
+		struct kuc_hdr lh;
+
+		lh.kuc_magic = KUC_MAGIC;
+		lh.kuc_transport = KUC_TRANSPORT_GENERIC;
+		lh.kuc_msgtype = KUC_MSG_SHUTDOWN;
+		lh.kuc_msglen = sizeof(lh);
+		libcfs_kkuc_group_put(group, &lh);
+	}
+
+	down_write(&kg_sem);
+	list_for_each_entry_safe(reg, next, &kkuc_groups[group], kr_chain) {
+		if ((uid == 0) || (uid == reg->kr_uid)) {
+			list_del(&reg->kr_chain);
+			CDEBUG(D_KUC, "Removed uid=%d fp=%p from group %d\n",
+			       reg->kr_uid, reg->kr_fp, group);
+			if (reg->kr_fp != NULL)
+				fput(reg->kr_fp);
+			if (pdata)
+				*pdata = reg->kr_data;
+			kfree(reg);
+		}
+	}
+	up_write(&kg_sem);
+
+	return 0;
+}
+EXPORT_SYMBOL(libcfs_kkuc_group_rem);
+
+int libcfs_kkuc_group_put(int group, void *payload)
+{
+	struct kkuc_reg	*reg;
+	int		 rc = 0;
+	int one_success = 0;
+
+	down_write(&kg_sem);
+	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
+		if (reg->kr_fp != NULL) {
+			rc = libcfs_kkuc_msg_put(reg->kr_fp, payload);
+			if (rc == 0)
+				one_success = 1;
+			else if (rc == -EPIPE) {
+				fput(reg->kr_fp);
+				reg->kr_fp = NULL;
+			}
+		}
+	}
+	up_write(&kg_sem);
+
+	/* don't return an error if the message has been delivered
+	 * at least to one agent */
+	if (one_success)
+		rc = 0;
+
+	return rc;
+}
+EXPORT_SYMBOL(libcfs_kkuc_group_put);
+
+/**
+ * Calls a callback function for each link of the given kuc group.
+ * @param group the group to call the function on.
+ * @param cb_func the function to be called.
+ * @param cb_arg extra argument to be passed to the callback function.
+ */
+int libcfs_kkuc_group_foreach(int group, libcfs_kkuc_cb_t cb_func,
+			      void *cb_arg)
+{
+	struct kkuc_reg *reg;
+	int rc = 0;
+
+	if (group > KUC_GRP_MAX) {
+		CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
+		return -EINVAL;
+	}
+
+	/* no link for this group */
+	if (kkuc_groups[group].next == NULL)
+		return 0;
+
+	down_read(&kg_sem);
+	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
+		if (reg->kr_fp != NULL)
+			rc = cb_func(reg->kr_data, cb_arg);
+	}
+	up_read(&kg_sem);
+
+	return rc;
+}
+EXPORT_SYMBOL(libcfs_kkuc_group_foreach);