9p patches for 6.3 merge window (part 1)

Here is the 9p patches for the 6.3 merge window combining
 the tested and reviewed patches from both Dominique's
 for-next tree and my for-next tree.  Most of these
 patches have been in for-next since December with only
 some reword in the description:
 
 - some fixes and cleanup setting up for a larger set
   of performance patches I've been working on
 - a contributed fixes relating to 9p/rdma
 - some contributed fixes relating to 9p/xen
 
 I've marked this as part 1, I'm not sure I'll be
 submitting part 2.  There were several performance
 patches that I wanted to get in, but the revisions
 after review only went out last week so while they
 have been tested, I haven't received reviews on the
 revisions.
 
 Its been about a decade since I've submitted a pull
 request, sorry if I messed anything up.
 
        -eric
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Merge tag '9p-6.3-for-linus-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull 9p updates from Eric Van Hensbergen:

 - some fixes and cleanup setting up for a larger set of performance
   patches I've been working on

 - a contributed fixes relating to 9p/rdma

 - some contributed fixes relating to 9p/xen

* tag '9p-6.3-for-linus-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: fix error reporting in v9fs_dir_release
  net/9p: fix bug in client create for .L
  9p/rdma: unmap receive dma buffer in rdma_request()/post_recv()
  9p/xen: fix connection sequence
  9p/xen: fix version parsing
  fs/9p: Expand setup of writeback cache to all levels
  net/9p: Adjust maximum MSIZE to account for p9 header

fs/9p/v9fs.c

@@ -468,7 +468,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 
 #ifdef CONFIG_9P_FSCACHE
 	/* register the session for caching */
-	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+	if (v9ses->cache == CACHE_FSCACHE) {
 		rc = v9fs_cache_session_get_cookie(v9ses, dev_name);
 		if (rc < 0)
 			goto err_clnt;

fs/9p/vfs_addr.c

@@ -279,8 +279,6 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	BUG_ON(!v9inode->writeback_fid);
-
 	/* Prefetch area to be written into the cache if we're caching this
 	 * file.  We need to do this before we get a lock on the page in case
 	 * there's more than one writer competing for the same cache block.

fs/9p/vfs_dir.c

@@ -197,7 +197,7 @@ static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
 
 
 /**
- * v9fs_dir_release - close a directory
+ * v9fs_dir_release - called on a close of a file or directory
  * @inode: inode of the directory
  * @filp: file pointer to a directory
  *
@@ -209,6 +209,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 	struct p9_fid *fid;
 	__le32 version;
 	loff_t i_size;
+	int retval = 0;
 
 	fid = filp->private_data;
 	p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
@@ -217,7 +218,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 		spin_lock(&inode->i_lock);
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
-		p9_fid_put(fid);
+		retval = p9_fid_put(fid);
 	}
 
 	if ((filp->f_mode & FMODE_WRITE)) {
@@ -228,7 +229,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 	} else {
 		fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL);
 	}
-	return 0;
+	return retval;
 }
 
 const struct file_operations v9fs_dir_operations = {

fs/9p/vfs_file.c

@@ -74,8 +74,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 	}
 
 	mutex_lock(&v9inode->v_mutex);
-	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
-	    !v9inode->writeback_fid &&
+	if ((v9ses->cache) && !v9inode->writeback_fid &&
 	    ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -93,9 +92,11 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 		v9inode->writeback_fid = (void *) writeback_fid;
 	}
 	mutex_unlock(&v9inode->v_mutex);
-	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+#ifdef CONFIG_9P_FSCACHE
+	if (v9ses->cache == CACHE_FSCACHE)
 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 				   file->f_mode & FMODE_WRITE);
+#endif
 	v9fs_open_fid_add(inode, &fid);
 	return 0;
 out_error:

fs/9p/vfs_inode.c

@@ -843,8 +843,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	inode = d_inode(dentry);
 	v9inode = V9FS_I(inode);
 	mutex_lock(&v9inode->v_mutex);
-	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
-	    !v9inode->writeback_fid &&
+	if ((v9ses->cache) && !v9inode->writeback_fid &&
 	    ((flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid

fs/9p/vfs_inode_dotl.c

@@ -316,8 +316,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 
 	v9inode = V9FS_I(inode);
 	mutex_lock(&v9inode->v_mutex);
-	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
-	    !v9inode->writeback_fid &&
+	if ((v9ses->cache) && !v9inode->writeback_fid &&
 	    ((flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -340,9 +339,11 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 	if (err)
 		goto out;
 	file->private_data = ofid;
-	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+#ifdef CONFIG_9P_FSCACHE
+	if (v9ses->cache == CACHE_FSCACHE)
 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 				   file->f_mode & FMODE_WRITE);
+#endif
 	v9fs_open_fid_add(inode, &ofid);
 	file->f_mode |= FMODE_CREATED;
 out:

net/9p/client.c

@@ -28,7 +28,11 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/9p.h>
 
-#define DEFAULT_MSIZE (128 * 1024)
+/* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
+ * room for write (16 extra) or read (11 extra) operands.
+ */
+
+#define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
 
 /* Client Option Parsing (code inspired by NFS code)
  *  - a little lazy - parse all client options
@@ -1289,7 +1293,7 @@ int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
 		 qid->type, qid->path, qid->version, iounit);
 
 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
-	ofid->mode = mode;
+	ofid->mode = flags;
 	ofid->iounit = iounit;
 
 free_and_error:

net/9p/trans_rdma.c

@@ -385,6 +385,7 @@ post_recv(struct p9_client *client, struct p9_rdma_context *c)
 	struct p9_trans_rdma *rdma = client->trans;
 	struct ib_recv_wr wr;
 	struct ib_sge sge;
+	int ret;
 
 	c->busa = ib_dma_map_single(rdma->cm_id->device,
 				    c->rc.sdata, client->msize,
@@ -402,7 +403,12 @@ post_recv(struct p9_client *client, struct p9_rdma_context *c)
 	wr.wr_cqe = &c->cqe;
 	wr.sg_list = &sge;
 	wr.num_sge = 1;
-	return ib_post_recv(rdma->qp, &wr, NULL);
+
+	ret = ib_post_recv(rdma->qp, &wr, NULL);
+	if (ret)
+		ib_dma_unmap_single(rdma->cm_id->device, c->busa,
+				    client->msize, DMA_FROM_DEVICE);
+	return ret;
 
  error:
 	p9_debug(P9_DEBUG_ERROR, "EIO\n");
@@ -499,7 +505,7 @@ dont_need_post_recv:
 
 	if (down_interruptible(&rdma->sq_sem)) {
 		err = -EINTR;
-		goto send_error;
+		goto dma_unmap;
 	}
 
 	/* Mark request as `sent' *before* we actually send it,
@@ -509,11 +515,14 @@ dont_need_post_recv:
 	WRITE_ONCE(req->status, REQ_STATUS_SENT);
 	err = ib_post_send(rdma->qp, &wr, NULL);
 	if (err)
-		goto send_error;
+		goto dma_unmap;
 
 	/* Success */
 	return 0;
 
+dma_unmap:
+	ib_dma_unmap_single(rdma->cm_id->device, c->busa,
+			    c->req->tc.size, DMA_TO_DEVICE);
  /* Handle errors that happened during or while preparing the send: */
  send_error:
 	WRITE_ONCE(req->status, REQ_STATUS_ERROR);

net/9p/trans_xen.c

@@ -372,19 +372,24 @@ out:
 	return ret;
 }
 
-static int xen_9pfs_front_probe(struct xenbus_device *dev,
-				const struct xenbus_device_id *id)
+static int xen_9pfs_front_init(struct xenbus_device *dev)
 {
 	int ret, i;
 	struct xenbus_transaction xbt;
-	struct xen_9pfs_front_priv *priv = NULL;
-	char *versions;
+	struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev);
+	char *versions, *v;
 	unsigned int max_rings, max_ring_order, len = 0;
 
 	versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
 	if (IS_ERR(versions))
 		return PTR_ERR(versions);
-	if (strcmp(versions, "1")) {
+	for (v = versions; *v; v++) {
+		if (simple_strtoul(v, &v, 10) == 1) {
+			v = NULL;
+			break;
+		}
+	}
+	if (v) {
 		kfree(versions);
 		return -EINVAL;
 	}
@@ -399,11 +404,6 @@ static int xen_9pfs_front_probe(struct xenbus_device *dev,
 	if (p9_xen_trans.maxsize > XEN_FLEX_RING_SIZE(max_ring_order))
 		p9_xen_trans.maxsize = XEN_FLEX_RING_SIZE(max_ring_order) / 2;
 
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-
-	priv->dev = dev;
 	priv->num_rings = XEN_9PFS_NUM_RINGS;
 	priv->rings = kcalloc(priv->num_rings, sizeof(*priv->rings),
 			      GFP_KERNEL);
@@ -462,23 +462,35 @@ static int xen_9pfs_front_probe(struct xenbus_device *dev,
 		goto error;
 	}
 
-	write_lock(&xen_9pfs_lock);
-	list_add_tail(&priv->list, &xen_9pfs_devs);
-	write_unlock(&xen_9pfs_lock);
-	dev_set_drvdata(&dev->dev, priv);
-	xenbus_switch_state(dev, XenbusStateInitialised);
-
 	return 0;
 
  error_xenbus:
 	xenbus_transaction_end(xbt, 1);
 	xenbus_dev_fatal(dev, ret, "writing xenstore");
  error:
-	dev_set_drvdata(&dev->dev, NULL);
 	xen_9pfs_front_free(priv);
 	return ret;
 }
 
+static int xen_9pfs_front_probe(struct xenbus_device *dev,
+				const struct xenbus_device_id *id)
+{
+	struct xen_9pfs_front_priv *priv = NULL;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+	dev_set_drvdata(&dev->dev, priv);
+
+	write_lock(&xen_9pfs_lock);
+	list_add_tail(&priv->list, &xen_9pfs_devs);
+	write_unlock(&xen_9pfs_lock);
+
+	return 0;
+}
+
 static int xen_9pfs_front_resume(struct xenbus_device *dev)
 {
 	dev_warn(&dev->dev, "suspend/resume unsupported\n");
@@ -497,6 +509,8 @@ static void xen_9pfs_front_changed(struct xenbus_device *dev,
 		break;
 
 	case XenbusStateInitWait:
+		if (!xen_9pfs_front_init(dev))
+			xenbus_switch_state(dev, XenbusStateInitialised);
 		break;
 
 	case XenbusStateConnected: