This patch build the generic message format for simple_rpc_pipefs.
Messages
may simply be the header itself, although having an optional data payload
follow
the header allows much more flexibility. Additional it creates an
rpc_pipefs pipe
named @name at the root of the mounted rpc_pipefs filesystem.
If @wait_for_open is non-zero and an upcall is later queued but the
userland
end of the pipe has not yet been opened, the upcall will remain queued
until
the pipe is opened; otherwise, the upcall queueing will return with -EPIPE.
Alloc/init a generic pipefs message header and copy into its message body
an arbitrary data payload.
The implementation serve as generic, general-purpose message headers for
easy
rpc_pipefs I/O. When an upcall is made, the pipefs_hdr_t is assigned to a
struct rpc_pipe_msg and delivered therein.
When one thinks of an upcall "message", in simple_rpc_pipefs that's a
pipefs_hdr_t
(possibly with an attached message body). A struct rpc_pipe_msg is
actually only
the -vehicle- by which the "real" message is delivered and processed.
In order to queue a pipefs msg for an upcall to userspace, the code places
the calling
thread on @uplist, and block the thread to wait for a reply. If @timeout
is nonzero,
the thread will be blocked for at most @timeout jiffies. Once a reply is
received by
your downcall handler, call pipefs_assign_upcall_reply() with @uplist to
find the
corresponding upcall, assign the reply, and wake the waiting thread.
At the end of the creation of the "message" the return value pointer may
be an error
that will be checked with IS_ERR() before attempting to access the reply
message.
Callers are responsible for freeing @msg, unless
pipefs_generic_destroy_msg()
is used as the ->destroy_msg() callback and the PIPEFS_AUTOFREE_UPCALL_MSG
flag is set in @upflags.
Signed-off-by: Sorin Faibish <sfaibish@xxxxxxxxxxx>
---
include/linux/sunrpc/rpc_pipe_fs.h | 4 +
include/linux/sunrpc/simple_rpc_pipefs.h | 112 ++++++++
net/sunrpc/Makefile | 2 +-
net/sunrpc/simple_rpc_pipefs.c | 423
++++++++++++++++++++++++++++++
4 files changed, 540 insertions(+), 1 deletions(-)
create mode 100644 include/linux/sunrpc/simple_rpc_pipefs.h
create mode 100644 net/sunrpc/simple_rpc_pipefs.c
diff --git a/include/linux/sunrpc/rpc_pipe_fs.h
b/include/linux/sunrpc/rpc_pipe_fs.h
index 6f942c9..2177d50 100644
--- a/include/linux/sunrpc/rpc_pipe_fs.h
+++ b/include/linux/sunrpc/rpc_pipe_fs.h
@@ -12,6 +12,10 @@ struct rpc_pipe_msg {
size_t len;
size_t copied;
int errno;
+#define PIPEFS_AUTOFREE_RPCMSG 0x01 /* frees rpc_pipe_msg */
+#define PIPEFS_AUTOFREE_RPCMSG_DATA 0x02 /* frees rpc_pipe_msg->data */
+#define PIPEFS_AUTOFREE_UPCALL_MSG PIPEFS_AUTOFREE_RPCMSG_DATA
+ u8 flags;
};
struct rpc_pipe_ops {
diff --git a/include/linux/sunrpc/simple_rpc_pipefs.h
b/include/linux/sunrpc/simple_rpc_pipefs.h
new file mode 100644
index 0000000..b51ef31
--- /dev/null
+++ b/include/linux/sunrpc/simple_rpc_pipefs.h
@@ -0,0 +1,112 @@
+/*
+ * linux/fs/gfs2/simple_rpc_pipefs.h
+ *
+ * Copyright (c) 2008 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * David M. Richter <richterd@xxxxxxxxxxxxxx>
+ *
+ * Drawing on work done by Andy Adamson <andros@xxxxxxxxxxxxxx> and
+ * Marius Eriksen <marius@xxxxxxxxxx>. Thanks for the help over the
+ * years, guys.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the University nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * With thanks to CITI's project sponsor and partner, IBM.
+ */
+
+#ifndef _SIMPLE_RPC_PIPEFS_H_
+#define _SIMPLE_RPC_PIPEFS_H_
+
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mount.h>
+#include <linux/sched.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+
+
+#define payload_of(headerp) ((void *)(headerp + 1))
+
+/*
+ * pipefs_hdr_t -- the generic message format for simple_rpc_pipefs.
Messages
+ * may simply be the header itself, although having an optional data
payload
+ * follow the header allows much more flexibility.
+ *
+ * Messages are created using pipefs_alloc_init_msg() and
+ * pipefs_alloc_init_msg_padded(), both of which accept a pointer to an
+ * (optional) data payload.
+ *
+ * Given a pipefs_hdr_t *msg that has a struct foo payload, the data can
be
+ * accessed using: struct foo *foop = payload_of(msg)
+ */
+typedef struct pipefs_hdr {
+ u32 msgid;
+ u8 type;
+ u8 flags;
+ u16 totallen; /* length of entire message, including hdr itself */
+ u32 status;
+} pipefs_hdr_t;
+
+/*
+ * pipefs_list_t -- a type of list used for tracking callers who've made
an
+ * upcall and are blocked waiting for a reply.
+ *
+ * See pipefs_queue_upcall_waitreply() and pipefs_assign_upcall_reply().
+ */
+typedef struct pipefs_list {
+ struct list_head list;
+ spinlock_t list_lock;
+} pipefs_list_t;
+
+
+/* See net/sunrpc/simple_rpc_pipefs.c for more info on using these
functions. */
+extern struct dentry *pipefs_mkpipe(const char *name,
+ struct rpc_pipe_ops *ops,
+ int wait_for_open);
+extern void pipefs_closepipe(struct dentry *pipe);
+extern void pipefs_init_list(pipefs_list_t *list);
+extern pipefs_hdr_t *pipefs_alloc_init_msg(u32 msgid, u8 type, u8 flags,
+ void *data, u16 datalen);
+extern pipefs_hdr_t *pipefs_alloc_init_msg_padded(u32 msgid, u8 type,
+ u8 flags, void *data,
+ u16 datalen, u16 padlen);
+extern pipefs_hdr_t *pipefs_queue_upcall_waitreply(struct dentry *pipe,
+ pipefs_hdr_t *msg,
+ pipefs_list_t *uplist,
+ u8 upflags, u32 timeout);
+extern int pipefs_queue_upcall_noreply(struct dentry *pipe, pipefs_hdr_t
*msg,
+ u8 upflags);
+extern int pipefs_assign_upcall_reply(pipefs_hdr_t *reply,
+ pipefs_list_t *uplist);
+extern pipefs_hdr_t *pipefs_readmsg(struct file *filp, const char __user
*src,
+ size_t len);
+extern ssize_t pipefs_generic_upcall(struct file *filp,
+ struct rpc_pipe_msg *rpcmsg,
+ char __user *dst, size_t buflen);
+extern void pipefs_generic_destroy_msg(struct rpc_pipe_msg *rpcmsg);
+
+#endif /* _SIMPLE_RPC_PIPEFS_H_ */
diff --git a/net/sunrpc/Makefile b/net/sunrpc/Makefile
index 9d2fca5..e102040 100644
--- a/net/sunrpc/Makefile
+++ b/net/sunrpc/Makefile
@@ -12,7 +12,7 @@ sunrpc-y := clnt.o xprt.o socklib.o xprtsock.o sched.o \
svc.o svcsock.o svcauth.o svcauth_unix.o \
addr.o rpcb_clnt.o timer.o xdr.o \
sunrpc_syms.o cache.o rpc_pipe.o \
- svc_xprt.o
+ svc_xprt.o simple_rpc_pipefs.o
sunrpc-$(CONFIG_NFS_V4_1) += backchannel_rqst.o bc_svc.o
sunrpc-$(CONFIG_PROC_FS) += stats.o
sunrpc-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/net/sunrpc/simple_rpc_pipefs.c
b/net/sunrpc/simple_rpc_pipefs.c
new file mode 100644
index 0000000..13cf1a2
--- /dev/null
+++ b/net/sunrpc/simple_rpc_pipefs.c
@@ -0,0 +1,423 @@
+/*
+ * net/sunrpc/simple_rpc_pipefs.c
+ *
+ * Copyright (c) 2008 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * David M. Richter <richterd@xxxxxxxxxxxxxx>
+ *
+ * Drawing on work done by Andy Adamson <andros@xxxxxxxxxxxxxx> and
+ * Marius Eriksen <marius@xxxxxxxxxx>. Thanks for the help over the
+ * years, guys.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the University nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * With thanks to CITI's project sponsor and partner, IBM.
+ */
+
+#include <linux/completion.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/sunrpc/simple_rpc_pipefs.h>
+
+
+/*
+ * Make an rpc_pipefs pipe named @name at the root of the mounted
rpc_pipefs
+ * filesystem.
+ *
+ * If @wait_for_open is non-zero and an upcall is later queued but the
userland
+ * end of the pipe has not yet been opened, the upcall will remain queued
until
+ * the pipe is opened; otherwise, the upcall queueing will return with
-EPIPE.
+ */
+struct dentry* pipefs_mkpipe(const char *name, struct rpc_pipe_ops *ops,
+ int wait_for_open)
+{
+ struct dentry *dir, *pipe;
+ struct vfsmount *mnt;
+
+ mnt = rpc_get_mount();
+ if (IS_ERR(mnt)) {
+ pipe = ERR_CAST(mnt);
+ goto out;
+ }
+ dir = mnt->mnt_root;
+ if (!dir) {
+ pipe = ERR_PTR(-ENOENT);
+ goto out;
+ }
+ pipe = rpc_mkpipe(dir, name, NULL, ops,
+ wait_for_open ? RPC_PIPE_WAIT_FOR_OPEN : 0);
+out:
+ return pipe;
+}
+EXPORT_SYMBOL(pipefs_mkpipe);
+
+/*
+ * Shutdown a pipe made by pipefs_mkpipe().
+ * XXX: do we need to retain an extra reference on the mount?
+ */
+void pipefs_closepipe(struct dentry *pipe)
+{
+ rpc_unlink(pipe);
+ rpc_put_mount();
+}
+EXPORT_SYMBOL(pipefs_closepipe);
+
+/*
+ * Initialize a pipefs_list_t -- which are a way to keep track of callers
+ * who're blocked having made an upcall and are awaiting a reply.
+ *
+ * See pipefs_queue_upcall_waitreply() and pipefs_find_upcall_msgid() for
how
+ * to use them.
+ */
+inline void pipefs_init_list(pipefs_list_t *list)
+{
+ INIT_LIST_HEAD(&list->list);
+ spin_lock_init(&list->list_lock);
+}
+EXPORT_SYMBOL(pipefs_init_list);
+
+/*
+ * Alloc/init a generic pipefs message header and copy into its message
body
+ * an arbitrary data payload.
+ *
+ * pipefs_hdr_t's are meant to serve as generic, general-purpose message
+ * headers for easy rpc_pipefs I/O. When an upcall is made, the
+ * pipefs_hdr_t is assigned to a struct rpc_pipe_msg and delivered
+ * therein. --And yes, the naming can seem a little confusing at first:
+ *
+ * When one thinks of an upcall "message", in simple_rpc_pipefs that's a
+ * pipefs_hdr_t (possibly with an attached message body). A
+ * struct rpc_pipe_msg is actually only the -vehicle- by which the "real"
+ * message is delivered and processed.
+ */
+pipefs_hdr_t* pipefs_alloc_init_msg_padded(u32 msgid, u8 type, u8 flags,
+ void *data, u16 datalen, u16 padlen)
+{
+ u16 totallen;
+ pipefs_hdr_t *msg = NULL;
+
+ totallen = sizeof(*msg) + datalen + padlen;
+ if (totallen > PAGE_SIZE) {
+ msg = ERR_PTR(-E2BIG);
+ goto out;
+ }
+
+ msg = kzalloc(totallen, GFP_KERNEL);
+ if (!msg) {
+ msg = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ msg->msgid = msgid;
+ msg->type = type;
+ msg->flags = flags;
+ msg->totallen = totallen;
+ memcpy(payload_of(msg), data, datalen);
+out:
+ return msg;
+}
+EXPORT_SYMBOL(pipefs_alloc_init_msg_padded);
+
+/*
+ * See the description of pipefs_alloc_init_msg_padded().
+ */
+pipefs_hdr_t* pipefs_alloc_init_msg(u32 msgid, u8 type, u8 flags,
+ void *data, u16 datalen)
+{
+ return pipefs_alloc_init_msg_padded(msgid, type, flags, data,
+ datalen, 0);
+}
+EXPORT_SYMBOL(pipefs_alloc_init_msg);
+
+
+static void pipefs_init_rpcmsg(struct rpc_pipe_msg *rpcmsg, pipefs_hdr_t
*msg,
+ u8 upflags)
+{
+ memset(rpcmsg, 0, sizeof(*rpcmsg));
+ rpcmsg->data = msg;
+ rpcmsg->len = msg->totallen;
+ rpcmsg->flags = upflags;
+}
+
+static struct rpc_pipe_msg* pipefs_alloc_init_rpcmsg(pipefs_hdr_t *msg,
+ u8 upflags)
+{
+ struct rpc_pipe_msg *rpcmsg;
+
+ rpcmsg = kmalloc(sizeof(*rpcmsg), GFP_KERNEL);
+ if (!rpcmsg)
+ return ERR_PTR(-ENOMEM);
+
+ pipefs_init_rpcmsg(rpcmsg, msg, upflags);
+ return rpcmsg;
+}
+
+
+/* represents an upcall that'll block and wait for a reply */
+typedef struct pipefs_upcall {
+ u32 msgid;
+ struct rpc_pipe_msg rpcmsg;
+ struct list_head list;
+ wait_queue_head_t waitq;
+ struct pipefs_hdr *reply;
+} pipefs_upcall_t;
+
+
+static void pipefs_init_upcall_waitreply(pipefs_upcall_t *upcall,
+ pipefs_hdr_t *msg, u8 upflags)
+{
+ upcall->reply = NULL;
+ upcall->msgid = msg->msgid;
+ INIT_LIST_HEAD(&upcall->list);
+ init_waitqueue_head(&upcall->waitq);
+ pipefs_init_rpcmsg(&upcall->rpcmsg, msg, upflags);
+}
+
+static int __pipefs_queue_upcall_waitreply(struct dentry *pipe,
+ pipefs_upcall_t *upcall,
+ pipefs_list_t *uplist, u32 timeout)
+{
+ int err = 0;
+ DECLARE_WAITQUEUE(wq, current);
+
+ add_wait_queue(&upcall->waitq, &wq);
+ spin_lock(&uplist->list_lock);
+ list_add(&upcall->list, &uplist->list);
+ spin_unlock(&uplist->list_lock);
+
+ err = rpc_queue_upcall(pipe->d_inode, &upcall->rpcmsg);
+ if (err < 0)
+ goto out;
+
+ if (timeout) {
+ /* retval of 0 means timer expired */
+ err = schedule_timeout_uninterruptible(timeout);
+ if (err == 0 && upcall->reply == NULL)
+ err = -ETIMEDOUT;
+ } else {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule();
+ __set_current_state(TASK_RUNNING);
+ }
+
+out:
+ spin_lock(&uplist->list_lock);
+ list_del_init(&upcall->list);
+ spin_unlock(&uplist->list_lock);
+ remove_wait_queue(&upcall->waitq, &wq);
+ return err;
+}
+
+/*
+ * Queue a pipefs msg for an upcall to userspace, place the calling thread
+ * on @uplist, and block the thread to wait for a reply. If @timeout is
+ * nonzero, the thread will be blocked for at most @timeout jiffies.
+ *
+ * (To convert time units into jiffies, consider the functions
+ * msecs_to_jiffies(), usecs_to_jiffies(), timeval_to_jiffies(), and
+ * timespec_to_jiffies().)
+ *
+ * Once a reply is received by your downcall handler, call
+ * pipefs_assign_upcall_reply() with @uplist to find the corresponding
upcall,
+ * assign the reply, and wake the waiting thread.
+ *
+ * This function's return value pointer may be an error and should be
checked
+ * with IS_ERR() before attempting to access the reply message.
+ *
+ * Callers are responsible for freeing @msg, unless
pipefs_generic_destroy_msg()
+ * is used as the ->destroy_msg() callback and the
PIPEFS_AUTOFREE_UPCALL_MSG
+ * flag is set in @upflags. See also rpc_pipe_fs.h.
+ */
+pipefs_hdr_t *pipefs_queue_upcall_waitreply(struct dentry *pipe,
+ pipefs_hdr_t *msg,
+ pipefs_list_t *uplist,
+ u8 upflags, u32 timeout)
+{
+ int err = 0;
+ pipefs_upcall_t upcall;
+
+ pipefs_init_upcall_waitreply(&upcall, msg, upflags);
+ err = __pipefs_queue_upcall_waitreply(pipe, &upcall, uplist, timeout);
+ if (err < 0) {
+ kfree(upcall.reply);
+ upcall.reply = ERR_PTR(err);
+ }
+
+ return upcall.reply;
+}
+EXPORT_SYMBOL(pipefs_queue_upcall_waitreply);
+
+/*
+ * Queue a pipefs msg for an upcall to userspace and immediately return
(i.e.,
+ * no reply is expected).
+ *
+ * Callers are responsible for freeing @msg, unless
pipefs_generic_destroy_msg()
+ * is used as the ->destroy_msg() callback and the
PIPEFS_AUTOFREE_UPCALL_MSG
+ * flag is set in @upflags. See also rpc_pipe_fs.h.
+ */
+int pipefs_queue_upcall_noreply(struct dentry *pipe, pipefs_hdr_t *msg,
+ u8 upflags)
+{
+ int err = 0;
+ struct rpc_pipe_msg *rpcmsg;
+
+ upflags |= PIPEFS_AUTOFREE_RPCMSG;
+ rpcmsg = pipefs_alloc_init_rpcmsg(msg, upflags);
+ if (IS_ERR(rpcmsg)) {
+ err = PTR_ERR(rpcmsg);
+ goto out;
+ }
+ err = rpc_queue_upcall(pipe->d_inode, rpcmsg);
+out:
+ return err;
+}
+EXPORT_SYMBOL(pipefs_queue_upcall_noreply);
+
+
+static pipefs_upcall_t *pipefs_find_upcall_msgid(u32 msgid,
+ pipefs_list_t *uplist)
+{
+ pipefs_upcall_t *upcall;
+
+ spin_lock(&uplist->list_lock);
+ list_for_each_entry(upcall, &uplist->list, list)
+ if (upcall->msgid == msgid)
+ goto out;
+ upcall = NULL;
+out:
+ spin_unlock(&uplist->list_lock);
+ return upcall;
+}
+
+/*
+ * In your rpc_pipe_ops->downcall() handler, once you've read in a
downcall
+ * message and have determined that it is a reply to a waiting upcall,
+ * you can use this function to find the appropriate upcall, assign the
result,
+ * and wake the upcall thread.
+ *
+ * The reply message must have the same msgid as the original upcall
message's.
+ *
+ * See also pipefs_queue_upcall_waitreply() and pipefs_readmsg().
+ */
+int pipefs_assign_upcall_reply(pipefs_hdr_t *reply, pipefs_list_t *uplist)
+{
+ int err = 0;
+ pipefs_upcall_t *upcall;
+
+ upcall = pipefs_find_upcall_msgid(reply->msgid, uplist);
+ if (!upcall) {
+ printk(KERN_ERR "%s: ERROR: have reply but no matching upcall "
+ "for msgid %d\n", __func__, reply->msgid);
+ err = -ENOENT;
+ goto out;
+ }
+ upcall->reply = reply;
+ wake_up(&upcall->waitq);
+out:
+ return err;
+}
+EXPORT_SYMBOL(pipefs_assign_upcall_reply);
+
+/*
+ * Generic method to read-in and return a newly-allocated message which
begins
+ * with a pipefs_hdr_t.
+ */
+pipefs_hdr_t *pipefs_readmsg(struct file *filp, const char __user *src,
+ size_t len)
+{
+ int err = 0, hdrsize;
+ pipefs_hdr_t *msg = NULL;
+
+ hdrsize = sizeof(*msg);
+ if (len < hdrsize) {
+ printk(KERN_ERR "%s: ERROR: header is too short (%d vs %d)\n",
+ __func__, len, hdrsize);
+ err = -EINVAL;
+ goto out;
+ }
+
+ msg = kzalloc(len, GFP_KERNEL);
+ if (!msg) {
+ err = -ENOMEM;
+ goto out;
+ }
+ if (copy_from_user(msg, src, len))
+ err = -EFAULT;
+out:
+ if (err) {
+ kfree(msg);
+ msg = ERR_PTR(err);
+ }
+ return msg;
+}
+EXPORT_SYMBOL(pipefs_readmsg);
+
+/*
+ * Generic rpc_pipe_ops->upcall() handler implementation.
+ *
+ * Don't call this directly: to make an upcall, use
+ * pipefs_queue_upcall_waitreply() or pipefs_queue_upcall_noreply().
+ */
+ssize_t pipefs_generic_upcall(struct file *filp, struct rpc_pipe_msg
*rpcmsg,
+ char __user *dst, size_t buflen)
+{
+ char *data;
+ ssize_t len, left;
+
+ data = (char *)rpcmsg->data + rpcmsg->copied;
+ len = rpcmsg->len - rpcmsg->copied;
+ if (len > buflen)
+ len = buflen;
+
+ left = copy_to_user(dst, data, len);
+ if (left < 0) {
+ rpcmsg->errno = left;
+ return left;
+ }
+
+ len -= left;
+ rpcmsg->copied += len;
+ rpcmsg->errno = 0;
+ return len;
+}
+EXPORT_SYMBOL(pipefs_generic_upcall);
+
+/*
+ * Generic rpc_pipe_ops->destroy_msg() handler implementation.
+ *
+ * Items are only freed if @rpcmsg->flags has been set appropriately.
+ * See pipefs_queue_upcall_noreply() and rpc_pipe_fs.h.
+ */
+void pipefs_generic_destroy_msg(struct rpc_pipe_msg *rpcmsg)
+{
+ if (rpcmsg->flags & PIPEFS_AUTOFREE_UPCALL_MSG)
+ kfree(rpcmsg->data);
+ if (rpcmsg->flags & PIPEFS_AUTOFREE_RPCMSG)
+ kfree(rpcmsg);
+}
+EXPORT_SYMBOL(pipefs_generic_destroy_msg);
+
--
1.6.6.1
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