[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] [linux] Fix xenbus device to allow replies larger than 4096 bytes.
# HG changeset patch # User Christian Limpach <Christian.Limpach@xxxxxxxxxxxxx> # Date 1175076118 -3600 # Node ID f9d23364567aef2430c47ac6e451c6b7ed0bf959 # Parent 4c5ea17290fe4157d657d46d220f47a1a9ed8256 [linux] Fix xenbus device to allow replies larger than 4096 bytes. Also fix reply_queue mutex across fragmented replies and for concurrent readers. Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxxx> --- linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_dev.c | 86 +++++++++++++------ 1 files changed, 59 insertions(+), 27 deletions(-) diff -r 4c5ea17290fe -r f9d23364567a linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_dev.c --- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_dev.c Wed Mar 28 10:41:53 2007 +0100 +++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_dev.c Wed Mar 28 11:01:58 2007 +0100 @@ -58,6 +58,13 @@ 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; @@ -73,9 +80,7 @@ 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; @@ -88,18 +93,34 @@ static ssize_t xenbus_dev_read(struct fi size_t len, loff_t *ppos) { struct xenbus_dev_data *u = filp->private_data; - int i; - - 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++; - } + struct read_buffer *rb; + int i, ret; + + 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; } @@ -107,16 +128,20 @@ static void queue_reply(struct xenbus_de static void queue_reply(struct xenbus_dev_data *u, char *data, unsigned int len) { - int i; - - mutex_lock(&u->reply_mutex); - - for (i = 0; i < len; i++, u->read_prod++) - u->read_buffer[MASK_READ_IDX(u->read_prod)] = data[i]; - - BUG_ON((u->read_prod - u->read_cons) > sizeof(u->read_buffer)); - - mutex_unlock(&u->reply_mutex); + struct read_buffer *rb; + + if (len == 0) + return; + + rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); + BUG_ON(rb == NULL); + + rb->cons = 0; + rb->len = len; + + memcpy(rb->msg, data, len); + + list_add_tail(&rb->list, &u->read_buffers); wake_up(&u->read_waitq); } @@ -155,10 +180,12 @@ 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); @@ -230,8 +257,10 @@ 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; @@ -282,8 +311,10 @@ static ssize_t xenbus_dev_write(struct f hdr.type = msg_type; hdr.len = strlen(XS_RESP) + 1; + mutex_lock(&u->reply_mutex); queue_reply(u, (char *)&hdr, sizeof(hdr)); queue_reply(u, (char *)XS_RESP, hdr.len); + mutex_unlock(&u->reply_mutex); break; } @@ -312,6 +343,7 @@ 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); @@ -349,7 +381,7 @@ 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; } _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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