2007-11-06 18:04:19

by J. Bruce Fields

[permalink] [raw]
Subject: rpc_pipefs patches

I've been reading through rpc_pipefs and have some documentation and
minor cleanup. Please apply (unless they're crap or something).

--b.


2007-11-06 18:05:36

by J. Bruce Fields

[permalink] [raw]
Subject: [PATCH 1/2] sunrpc: rpc_pipe_poll may miss available data in some cases

From: J. Bruce Fields <[email protected]>

Pipe messages start out life on a queue on the inode, but when first
read they're moved to the filp's private pointer. So it's possible for
a poll here to return null even though there's a partially read message
available.

Signed-off-by: J. Bruce Fields <[email protected]>
---
net/sunrpc/rpc_pipe.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 18f0a8d..c59f3ca 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -280,7 +280,7 @@ rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
mask = POLLOUT | POLLWRNORM;
if (rpci->ops == NULL)
mask |= POLLERR | POLLHUP;
- if (!list_empty(&rpci->pipe))
+ if (filp->private_data || !list_empty(&rpci->pipe))
mask |= POLLIN | POLLRDNORM;
return mask;
}
--
1.5.3.5.561.g140d

2007-11-06 18:06:03

by J. Bruce Fields

[permalink] [raw]
Subject: [PATCH 2/2] sunrpc: document the rpc_pipefs kernel api

From: J. Bruce Fields <[email protected]>

Add kerneldoc comments for the rpc_pipefs.c functions that are exported.

Signed-off-by: J. Bruce Fields <[email protected]>
---
net/sunrpc/rpc_pipe.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 51 insertions(+), 1 deletions(-)

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index c59f3ca..5364e2e 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -76,6 +76,16 @@ rpc_timeout_upcall_queue(struct work_struct *work)
rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
}

+/**
+ * rpc_queue_upcall
+ * @inode: inode of upcall pipe on which to queue given message
+ * @msg: message to queue
+ *
+ * Call with an @inode created by rpc_mkpipe() to queue an upcall.
+ * A userspace process may then later read the upcall by performing a
+ * read on an open file for this inode. It is up to the caller to
+ * initialize the fields of @msg (other than @msg->list) appropriately.
+ */
int
rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
{
@@ -663,7 +673,16 @@ rpc_lookup_negative(char *path, struct nameidata *nd)
return dentry;
}

-
+/**
+ * rpc_mkdir - Create a new directory in rpc_pipefs
+ * @path: path from the rpc_pipefs root to the new directory
+ * @rpc_clnt: rpc client to associate with this directory
+ *
+ * This creates a directory at the given @path associated with
+ * @rpc_clnt, which will contain a file named "info" with some basic
+ * information about the client, together with any "pipes" that may
+ * later be created using rpc_mkpipe().
+ */
struct dentry *
rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
{
@@ -699,6 +718,10 @@ err_dput:
goto out;
}

+/**
+ * rpc_rmdir - Remove a directory created with rpc_mkdir()
+ * @dentry: directory to remove
+ */
int
rpc_rmdir(struct dentry *dentry)
{
@@ -717,6 +740,25 @@ rpc_rmdir(struct dentry *dentry)
return error;
}

+/**
+ * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
+ * @parent: dentry of directory to create new "pipe" in
+ * @name: name of pipe
+ * @private: private data to associate with the pipe, for the caller's use
+ * @ops: operations defining the behavior of the pipe: upcall, downcall,
+ * release_pipe, and destroy_msg.
+ *
+ * Data is made available for userspace to read by calls to
+ * rpc_queue_upcall(). The actual reads will result in calls to
+ * @ops->upcall, which will be called with the file pointer,
+ * message, and userspace buffer to copy to.
+ *
+ * Writes can come at any time, and do not necessarily have to be
+ * responses to upcalls. They will result in calls to @msg->downcall.
+ *
+ * The @private argument passed here will be available to all these methods
+ * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
+ */
struct dentry *
rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
{
@@ -764,6 +806,14 @@ err_dput:
goto out;
}

+/**
+ * rpc_unlink - remove a pipe
+ * @dentry: dentry for the pipe, as returned from rpc_mkpipe
+ *
+ * After this call, lookups will no longer find the pipe, and any
+ * attempts to read or write using preexisting opens of the pipe will
+ * return -EPIPE.
+ */
int
rpc_unlink(struct dentry *dentry)
{
--
1.5.3.5.561.g140d