Attachment 198351 Details for Bug 294691 – Backported patch from upstream to RHEL5

[patch] Backported patch from upstream to RHEL5

rhel5-xenbus-device.patch (text/plain), 4.14 KB, created by Flavio Leitner on 2007-09-18 13:36:14 UTC

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Creator: Flavio Leitner

Created: 2007-09-18 13:36:14 UTC

Size: 4.14 KB

patch

obsolete

>Index: linux-2.6.18.i386/drivers/xen/xenbus/xenbus_dev.c
>===================================================================
>--- linux-2.6.18.i386.orig/drivers/xen/xenbus/xenbus_dev.c
>+++ linux-2.6.18.i386/drivers/xen/xenbus/xenbus_dev.c
>@@ -53,6 +53,13 @@ struct xenbus_dev_transaction {
> 	struct xenbus_transaction handle;
> };
> 
>+struct read_buffer {
>+	struct list_head list;
>+	unsigned int cons;
>+	unsigned int len;
>+	char msg[];
>+};
>+
> struct xenbus_dev_data {
> 	/* In-progress transaction. */
> 	struct list_head transactions;
>@@ -68,9 +75,7 @@ struct xenbus_dev_data {
> 	} u;
> 
> 	/* Response queue. */
>-#define MASK_READ_IDX(idx) ((idx)&(PAGE_SIZE-1))
>-	char read_buffer[PAGE_SIZE];
>-	unsigned int read_cons, read_prod;
>+	struct list_head read_buffers;
> 	wait_queue_head_t read_waitq;
> 
> 	struct mutex reply_mutex;
>@@ -83,35 +88,55 @@ static ssize_t xenbus_dev_read(struct fi
> 			       size_t len, loff_t *ppos)
> {
> 	struct xenbus_dev_data *u = filp->private_data;
>-	int i;
>+	struct read_buffer *rb;
>+	int i, ret;
> 
>-	if (wait_event_interruptible(u->read_waitq,
>-				     u->read_prod != u->read_cons))
>-		return -EINTR;
>-
>-	for (i = 0; i < len; i++) {
>-		if (u->read_cons == u->read_prod)
>-			break;
>-		put_user(u->read_buffer[MASK_READ_IDX(u->read_cons)], ubuf+i);
>-		u->read_cons++;
>+	mutex_lock(&u->reply_mutex);
>+	while (list_empty(&u->read_buffers)) {
>+		mutex_unlock(&u->reply_mutex);
>+		ret = wait_event_interruptible(u->read_waitq,
>+					       !list_empty(&u->read_buffers));
>+		if (ret)
>+			return ret;
>+		mutex_lock(&u->reply_mutex);
> 	}
> 
>+	rb = list_entry(u->read_buffers.next, struct read_buffer, list);
>+	for (i = 0; i < len;) {
>+		put_user(rb->msg[rb->cons], ubuf + i);
>+		i++;
>+		rb->cons++;
>+		if (rb->cons == rb->len) {
>+			list_del(&rb->list);
>+			kfree(rb);
>+			if (list_empty(&u->read_buffers))
>+				break;
>+			rb = list_entry(u->read_buffers.next,
>+					struct read_buffer, list);
>+		}
>+	}
>+	mutex_unlock(&u->reply_mutex);
>+
> 	return i;
> }
> 
> static void queue_reply(struct xenbus_dev_data *u,
> 			char *data, unsigned int len)
> {
>-	int i;
>+	struct read_buffer *rb;
> 
>-	mutex_lock(&u->reply_mutex);
>+	if (len == 0)
>+		return;
> 
>-	for (i = 0; i < len; i++, u->read_prod++)
>-		u->read_buffer[MASK_READ_IDX(u->read_prod)] = data[i];
>+	rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL);
>+	BUG_ON(rb == NULL);
> 
>-	BUG_ON((u->read_prod - u->read_cons) > sizeof(u->read_buffer));
>+	rb->cons = 0;
>+	rb->len = len;
> 
>-	mutex_unlock(&u->reply_mutex);
>+	memcpy(rb->msg, data, len);
>+
>+	list_add_tail(&rb->list, &u->read_buffers);
> 
> 	wake_up(&u->read_waitq);
> }
>@@ -150,10 +175,12 @@ static void watch_fired(struct xenbus_wa
> 
> 	hdr.type = XS_WATCH_EVENT;
> 	hdr.len = body_len;
>-	
>+
>+	mutex_lock(&adap->dev_data->reply_mutex);
> 	queue_reply(adap->dev_data, (char *)&hdr, sizeof(hdr));
> 	queue_reply(adap->dev_data, (char *)path, path_len);
> 	queue_reply(adap->dev_data, (char *)token, tok_len);
>+	mutex_unlock(&adap->dev_data->reply_mutex);
> }
> 
> static LIST_HEAD(watch_list);
>@@ -217,8 +244,10 @@ static ssize_t xenbus_dev_write(struct f
> 			list_del(&trans->list);
> 			kfree(trans);
> 		}
>+		mutex_lock(&u->reply_mutex);
> 		queue_reply(u, (char *)&u->u.msg, sizeof(u->u.msg));
> 		queue_reply(u, (char *)reply, u->u.msg.len);
>+		mutex_unlock(&u->reply_mutex);
> 		kfree(reply);
> 		break;
> 
>@@ -253,8 +282,10 @@ static ssize_t xenbus_dev_write(struct f
> 
> 			hdr.type = XS_WATCH;
> 			hdr.len = strlen(XS_WATCH_RESP) + 1;
>+			mutex_lock(&u->reply_mutex);
> 			queue_reply(u, (char *)&hdr, sizeof(hdr));
> 			queue_reply(u, (char *)XS_WATCH_RESP, hdr.len);
>+			mutex_unlock(&u->reply_mutex);
> 		} else {
> 			list_for_each_entry_safe(watch, tmp_watch,
>                                                  &u->watches, list) {
>@@ -295,6 +326,7 @@ static int xenbus_dev_open(struct inode 
> 
> 	INIT_LIST_HEAD(&u->transactions);
> 	INIT_LIST_HEAD(&u->watches);
>+	INIT_LIST_HEAD(&u->read_buffers);
> 	init_waitqueue_head(&u->read_waitq);
> 
> 	mutex_init(&u->reply_mutex);
>@@ -332,7 +364,7 @@ static unsigned int xenbus_dev_poll(stru
> 	struct xenbus_dev_data *u = file->private_data;
> 
> 	poll_wait(file, &u->read_waitq, wait);
>-	if (u->read_cons != u->read_prod)
>+	if (!list_empty(&u->read_buffers))
> 		return POLLIN | POLLRDNORM;
> 	return 0;
> }

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Attachments on bug 294691: 198351