This removes the aio implementation from the usb gadget file system. Aside
from making very creative (!) use of the aio retry path, it can't be of any
use performance-wise because it always kmalloc()s a bounce buffer for the
*whole* I/O size. Perhaps the only reason to keep it around is the ability
to cancel I/O requests, which only applies when using the user space async
I/O interface. I highly doubt that is enough incentive to justify the extra
complexity here or in user-space, so I think it's a safe bet to remove this.
If that feature still desired, it would be possible to implement a sync
interface that does an interruptible sleep.
I can be convinced otherwise, but the alternatives are difficult. See for
example the "fuse, get_user_pages, flush_anon_page, aliasing caches and all
that again" LKML thread recently for why it's waaay easier to kmalloc a
bounce buffer here, and (ab)use the retry interface.
---
diff -urpN -X dontdiff a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c
--- a/drivers/usb/gadget/inode.c 2007-01-10 13:23:46.000000000 -0800
+++ b/drivers/usb/gadget/inode.c 2007-01-10 16:56:09.000000000 -0800
@@ -527,218 +527,6 @@ static int ep_ioctl (struct inode *inode
/*----------------------------------------------------------------------*/
-/* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
-
-struct kiocb_priv {
- struct usb_request *req;
- struct ep_data *epdata;
- void *buf;
- const struct iovec *iv;
- unsigned long nr_segs;
- unsigned actual;
-};
-
-static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e)
-{
- struct kiocb_priv *priv = iocb->private;
- struct ep_data *epdata;
- int value;
-
- local_irq_disable();
- epdata = priv->epdata;
- // spin_lock(&epdata->dev->lock);
- kiocbSetCancelled(iocb);
- if (likely(epdata && epdata->ep && priv->req))
- value = usb_ep_dequeue (epdata->ep, priv->req);
- else
- value = -EINVAL;
- // spin_unlock(&epdata->dev->lock);
- local_irq_enable();
-
- aio_put_req(iocb);
- return value;
-}
-
-static int ep_aio_read_retry(struct kiocb *iocb)
-{
- struct kiocb_priv *priv = iocb->private;
- ssize_t total;
- int i, err = 0;
-
- /* we "retry" to get the right mm context for this: */
-
- /* copy stuff into user buffers */
- total = priv->actual;
- for (i=0; i < priv->nr_segs; i++) {
- ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
-
- if (copy_to_user(priv->iv[i].iov_base, priv->buf, this)) {
- err = -EFAULT;
- break;
- }
-
- total -= this;
- if (total == 0)
- break;
- }
- kfree(priv->buf);
- kfree(priv);
- aio_put_req(iocb);
- return err;
-}
-
-static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
-{
- struct kiocb *iocb = req->context;
- struct kiocb_priv *priv = iocb->private;
- struct ep_data *epdata = priv->epdata;
-
- /* lock against disconnect (and ideally, cancel) */
- spin_lock(&epdata->dev->lock);
- priv->req = NULL;
- priv->epdata = NULL;
- if (priv->iv == NULL
- || unlikely(req->actual == 0)
- || unlikely(kiocbIsCancelled(iocb))) {
- kfree(req->buf);
- kfree(priv);
- iocb->private = NULL;
- /* aio_complete() reports bytes-transferred _and_ faults */
- if (unlikely(kiocbIsCancelled(iocb)))
- aio_put_req(iocb);
- else
- aio_complete(iocb, req->actual, req->status);
- } else {
- /* retry() won't report both; so we hide some faults */
- if (unlikely(0 != req->status))
- DBG(epdata->dev, "%s fault %d len %d\n",
- ep->name, req->status, req->actual);
-
- priv->buf = req->buf;
- priv->actual = req->actual;
- kick_iocb(iocb);
- }
- spin_unlock(&epdata->dev->lock);
-
- usb_ep_free_request(ep, req);
- put_ep(epdata);
-}
-
-static ssize_t
-ep_aio_rwtail(
- struct kiocb *iocb,
- char *buf,
- size_t len,
- struct ep_data *epdata,
- const struct iovec *iv,
- unsigned long nr_segs
-)
-{
- struct kiocb_priv *priv;
- struct usb_request *req;
- ssize_t value;
-
- priv = kmalloc(sizeof *priv, GFP_KERNEL);
- if (!priv) {
- value = -ENOMEM;
-fail:
- kfree(buf);
- return value;
- }
- iocb->private = priv;
- priv->iv = iv;
- priv->nr_segs = nr_segs;
-
- value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
- if (unlikely(value < 0)) {
- kfree(priv);
- goto fail;
- }
-
- iocb->ki_cancel = ep_aio_cancel;
- get_ep(epdata);
- priv->epdata = epdata;
- priv->actual = 0;
-
- /* each kiocb is coupled to one usb_request, but we can't
- * allocate or submit those if the host disconnected.
- */
- spin_lock_irq(&epdata->dev->lock);
- if (likely(epdata->ep)) {
- req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
- if (likely(req)) {
- priv->req = req;
- req->buf = buf;
- req->length = len;
- req->complete = ep_aio_complete;
- req->context = iocb;
- value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
- if (unlikely(0 != value))
- usb_ep_free_request(epdata->ep, req);
- } else
- value = -EAGAIN;
- } else
- value = -ENODEV;
- spin_unlock_irq(&epdata->dev->lock);
-
- up(&epdata->lock);
-
- if (unlikely(value)) {
- kfree(priv);
- put_ep(epdata);
- } else
- value = (iv ? -EIOCBRETRY : -EIOCBQUEUED);
- return value;
-}
-
-static ssize_t
-ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t o)
-{
- struct ep_data *epdata = iocb->ki_filp->private_data;
- char *buf;
- size_t len = iov_length(iov, nr_segs);
-
- if (unlikely(epdata->desc.bEndpointAddress & USB_DIR_IN))
- return -EINVAL;
-
- buf = kmalloc(len, GFP_KERNEL);
- if (unlikely(!buf))
- return -ENOMEM;
-
- iocb->ki_retry = ep_aio_read_retry;
- return ep_aio_rwtail(iocb, buf, len, epdata, iov, nr_segs);
-}
-
-static ssize_t
-ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t o)
-{
- struct ep_data *epdata = iocb->ki_filp->private_data;
- char *buf;
- size_t len = 0;
- int i = 0;
-
- if (unlikely(!(epdata->desc.bEndpointAddress & USB_DIR_IN)))
- return -EINVAL;
-
- buf = kmalloc(iov_length(iov, nr_segs), GFP_KERNEL);
- if (unlikely(!buf))
- return -ENOMEM;
-
- for (i=0; i < nr_segs; i++) {
- if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
- iov[i].iov_len) != 0)) {
- kfree(buf);
- return -EFAULT;
- }
- len += iov[i].iov_len;
- }
- return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
-}
-
-/*----------------------------------------------------------------------*/
-
/* used after endpoint configuration */
static const struct file_operations ep_io_operations = {
.owner = THIS_MODULE,
@@ -748,9 +536,6 @@ static const struct file_operations ep_i
.write = ep_write,
.ioctl = ep_ioctl,
.release = ep_release,
-
- .aio_read = ep_aio_read,
- .aio_write = ep_aio_write,
};
/* ENDPOINT INITIALIZATION
-
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