diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c b/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c new file mode 100644 index 000000000000..d6d3b2e0f307 --- /dev/null +++ b/drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c @@ -0,0 +1,346 @@ +/* + * 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 <linux/libcfs/libcfs.h> + +#ifdef LUSTRE_UTILS +/* This is the userspace side. */ + +/** Start the userspace side of a KUC pipe. + * @param link Private descriptor for pipe/socket. + * @param groups KUC broadcast group to listen to + * (can be null for unicast to this pid) + */ +int libcfs_ukuc_start(lustre_kernelcomm *link, int group) +{ + int pfd[2]; + + if (pipe(pfd) < 0) + return -errno; + + memset(link, 0, sizeof(*link)); + link->lk_rfd = pfd[0]; + link->lk_wfd = pfd[1]; + link->lk_group = group; + link->lk_uid = getpid(); + return 0; +} + +int libcfs_ukuc_stop(lustre_kernelcomm *link) +{ + if (link->lk_wfd > 0) + close(link->lk_wfd); + return close(link->lk_rfd); +} + +#define lhsz sizeof(*kuch) + +/** Read a message from the link. + * Allocates memory, returns handle + * + * @param link Private descriptor for pipe/socket. + * @param buf Buffer to read into, must include size for kuc_hdr + * @param maxsize Maximum message size allowed + * @param transport Only listen to messages on this transport + * (and the generic transport) + */ +int libcfs_ukuc_msg_get(lustre_kernelcomm *link, char *buf, int maxsize, + int transport) +{ + struct kuc_hdr *kuch; + int rc = 0; + + memset(buf, 0, maxsize); + + CDEBUG(D_KUC, "Waiting for message from kernel on fd %d\n", + link->lk_rfd); + + while (1) { + /* Read header first to get message size */ + rc = read(link->lk_rfd, buf, lhsz); + if (rc <= 0) { + rc = -errno; + break; + } + kuch = (struct kuc_hdr *)buf; + + CDEBUG(D_KUC, "Received message mg=%x t=%d m=%d l=%d\n", + kuch->kuc_magic, kuch->kuc_transport, kuch->kuc_msgtype, + kuch->kuc_msglen); + + if (kuch->kuc_magic != KUC_MAGIC) { + CERROR("bad message magic %x != %x\n", + kuch->kuc_magic, KUC_MAGIC); + rc = -EPROTO; + break; + } + + if (kuch->kuc_msglen > maxsize) { + rc = -EMSGSIZE; + break; + } + + /* Read payload */ + rc = read(link->lk_rfd, buf + lhsz, kuch->kuc_msglen - lhsz); + if (rc < 0) { + rc = -errno; + break; + } + if (rc < (kuch->kuc_msglen - lhsz)) { + CERROR("short read: got %d of %d bytes\n", + rc, kuch->kuc_msglen); + rc = -EPROTO; + break; + } + + if (kuch->kuc_transport == transport || + kuch->kuc_transport == KUC_TRANSPORT_GENERIC) { + return 0; + } + /* Drop messages for other transports */ + } + return rc; +} + +#else /* LUSTRE_UTILS */ +/* 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 reigstration has a uid and a file pointer */ +struct kkuc_reg { + struct list_head kr_chain; + int kr_uid; + struct file *kr_fp; + __u32 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 identidier for this receiver + * @param group group number + */ +int libcfs_kkuc_group_add(struct file *filp, int uid, int group, __u32 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(®->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) +{ + struct kkuc_reg *reg, *next; + ENTRY; + + 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(®->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); + 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; + ENTRY; + + down_read(&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_read(&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 iextra 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; + ENTRY; + + 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); + +#endif /* LUSTRE_UTILS */ |