Merge branch 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull gadgetfs fixes from Al Viro:
 "Assorted fixes around AIO on gadgetfs: leaks, use-after-free, troubles
  caused by ->f_op flipping"

* 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  gadgetfs: really get rid of switching ->f_op
  gadgetfs: get rid of flipping ->f_op in ep_config()
  gadget: switch ep_io_operations to ->read_iter/->write_iter
  gadgetfs: use-after-free in ->aio_read()
  gadget/function/f_fs.c: switch to ->{read,write}_iter()
  gadget/function/f_fs.c: use put iov_iter into io_data
  gadget/function/f_fs.c: close leaks
  move iov_iter.c from mm/ to lib/
  new helper: dup_iter()

6 files changed, 291 insertions, 400 deletions

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index af98b096af2f..175c9956cbe3 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -144,10 +144,9 @@ struct ffs_io_data {
         bool read;
 
         struct kiocb *kiocb;
-        const struct iovec *iovec;
-        unsigned long nr_segs;
-        char __user *buf;
-        size_t len;
+        struct iov_iter data;
+        const void *to_free;
+        char *buf;
 
         struct mm_struct *mm;
         struct work_struct work;
@@ -649,29 +648,10 @@ static void ffs_user_copy_worker(struct work_struct *work)
                                          io_data->req->actual;
 
         if (io_data->read && ret > 0) {
-                int i;
-                size_t pos = 0;
-
-                /*
-                 * Since req->length may be bigger than io_data->len (after
-                 * being rounded up to maxpacketsize), we may end up with more
-                 * data then user space has space for.
-                 */
-                ret = min_t(int, ret, io_data->len);
-
                 use_mm(io_data->mm);
-                for (i = 0; i < io_data->nr_segs; i++) {
-                        size_t len = min_t(size_t, ret - pos,
-                                        io_data->iovec[i].iov_len);
-                        if (!len)
-                                break;
-                        if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
-                                                 &io_data->buf[pos], len))) {
-                                ret = -EFAULT;
-                                break;
-                        }
-                        pos += len;
-                }
+                ret = copy_to_iter(io_data->buf, ret, &io_data->data);
+                if (iov_iter_count(&io_data->data))
+                        ret = -EFAULT;
                 unuse_mm(io_data->mm);
         }
 
@@ -684,7 +664,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
 
         io_data->kiocb->private = NULL;
         if (io_data->read)
-                kfree(io_data->iovec);
+                kfree(io_data->to_free);
         kfree(io_data->buf);
         kfree(io_data);
 }
@@ -743,6 +723,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
                  * before the waiting completes, so do not assign to 'gadget' earlier
                  */
                 struct usb_gadget *gadget = epfile->ffs->gadget;
+                size_t copied;
 
                 spin_lock_irq(&epfile->ffs->eps_lock);
                 /* In the meantime, endpoint got disabled or changed. */
@@ -750,34 +731,21 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
                         spin_unlock_irq(&epfile->ffs->eps_lock);
                         return -ESHUTDOWN;
                 }
+                data_len = iov_iter_count(&io_data->data);
                 /*
                  * Controller may require buffer size to be aligned to
                  * maxpacketsize of an out endpoint.
                  */
-                data_len = io_data->read ?
-                           usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
-                           io_data->len;
+                if (io_data->read)
+                        data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
                 spin_unlock_irq(&epfile->ffs->eps_lock);
 
                 data = kmalloc(data_len, GFP_KERNEL);
                 if (unlikely(!data))
                         return -ENOMEM;
-                if (io_data->aio && !io_data->read) {
-                        int i;
-                        size_t pos = 0;
-                        for (i = 0; i < io_data->nr_segs; i++) {
-                                if (unlikely(copy_from_user(&data[pos],
-                                             io_data->iovec[i].iov_base,
-                                             io_data->iovec[i].iov_len))) {
-                                        ret = -EFAULT;
-                                        goto error;
-                                }
-                                pos += io_data->iovec[i].iov_len;
-                        }
-                } else {
-                        if (!io_data->read &&
-                            unlikely(__copy_from_user(data, io_data->buf,
-                                                      io_data->len))) {
+                if (!io_data->read) {
+                        copied = copy_from_iter(data, data_len, &io_data->data);
+                        if (copied != data_len) {
                                 ret = -EFAULT;
                                 goto error;
                         }
@@ -876,10 +844,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
                                  */
                                 ret = ep->status;
                                 if (io_data->read && ret > 0) {
-                                        ret = min_t(size_t, ret, io_data->len);
-
-                                        if (unlikely(copy_to_user(io_data->buf,
-                                                data, ret)))
+                                        ret = copy_to_iter(data, ret, &io_data->data);
+                                        if (unlikely(iov_iter_count(&io_data->data)))
                                                 ret = -EFAULT;
                                 }
                         }
@@ -898,37 +864,6 @@ error:
         return ret;
 }
 
-static ssize_t
-ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
-                 loff_t *ptr)
-{
-        struct ffs_io_data io_data;
-
-        ENTER();
-
-        io_data.aio = false;
-        io_data.read = false;
-        io_data.buf = (char * __user)buf;
-        io_data.len = len;
-
-        return ffs_epfile_io(file, &io_data);
-}
-
-static ssize_t
-ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
-{
-        struct ffs_io_data io_data;
-
-        ENTER();
-
-        io_data.aio = false;
-        io_data.read = true;
-        io_data.buf = buf;
-        io_data.len = len;
-
-        return ffs_epfile_io(file, &io_data);
-}
-
 static int
 ffs_epfile_open(struct inode *inode, struct file *file)
 {
@@ -965,67 +900,86 @@ static int ffs_aio_cancel(struct kiocb *kiocb)
         return value;
 }
 
-static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
-                                    const struct iovec *iovec,
-                                    unsigned long nr_segs, loff_t loff)
+static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 {
-        struct ffs_io_data *io_data;
+        struct ffs_io_data io_data, *p = &io_data;
+        ssize_t res;
 
         ENTER();
 
-        io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
-        if (unlikely(!io_data))
-                return -ENOMEM;
+        if (!is_sync_kiocb(kiocb)) {
+                p = kmalloc(sizeof(io_data), GFP_KERNEL);
+                if (unlikely(!p))
+                        return -ENOMEM;
+                p->aio = true;
+        } else {
+                p->aio = false;
+        }
 
-        io_data->aio = true;
-        io_data->read = false;
-        io_data->kiocb = kiocb;
-        io_data->iovec = iovec;
-        io_data->nr_segs = nr_segs;
-        io_data->len = kiocb->ki_nbytes;
-        io_data->mm = current->mm;
+        p->read = false;
+        p->kiocb = kiocb;
+        p->data = *from;
+        p->mm = current->mm;
 
-        kiocb->private = io_data;
+        kiocb->private = p;
 
         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 
-        return ffs_epfile_io(kiocb->ki_filp, io_data);
+        res = ffs_epfile_io(kiocb->ki_filp, p);
+        if (res == -EIOCBQUEUED)
+                return res;
+        if (p->aio)
+                kfree(p);
+        else
+                *from = p->data;
+        return res;
 }
 
-static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
-                                   const struct iovec *iovec,
-                                   unsigned long nr_segs, loff_t loff)
+static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 {
-        struct ffs_io_data *io_data;
-        struct iovec *iovec_copy;
+        struct ffs_io_data io_data, *p = &io_data;
+        ssize_t res;
 
         ENTER();
 
-        iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
-        if (unlikely(!iovec_copy))
-                return -ENOMEM;
-
-        memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
-
-        io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
-        if (unlikely(!io_data)) {
-                kfree(iovec_copy);
-                return -ENOMEM;
+        if (!is_sync_kiocb(kiocb)) {
+                p = kmalloc(sizeof(io_data), GFP_KERNEL);
+                if (unlikely(!p))
+                        return -ENOMEM;
+                p->aio = true;
+        } else {
+                p->aio = false;
         }
 
-        io_data->aio = true;
-        io_data->read = true;
-        io_data->kiocb = kiocb;
-        io_data->iovec = iovec_copy;
-        io_data->nr_segs = nr_segs;
-        io_data->len = kiocb->ki_nbytes;
-        io_data->mm = current->mm;
+        p->read = true;
+        p->kiocb = kiocb;
+        if (p->aio) {
+                p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
+                if (!p->to_free) {
+                        kfree(p);
+                        return -ENOMEM;
+                }
+        } else {
+                p->data = *to;
+                p->to_free = NULL;
+        }
+        p->mm = current->mm;
 
-        kiocb->private = io_data;
+        kiocb->private = p;
 
         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 
-        return ffs_epfile_io(kiocb->ki_filp, io_data);
+        res = ffs_epfile_io(kiocb->ki_filp, p);
+        if (res == -EIOCBQUEUED)
+                return res;
+
+        if (p->aio) {
+                kfree(p->to_free);
+                kfree(p);
+        } else {
+                *to = p->data;
+        }
+        return res;
 }
 
 static int
@@ -1105,10 +1059,10 @@ static const struct file_operations ffs_epfile_operations = {
         .llseek =       no_llseek,
 
         .open =         ffs_epfile_open,
-        .write =        ffs_epfile_write,
-        .read =         ffs_epfile_read,
-        .aio_write =    ffs_epfile_aio_write,
-        .aio_read =     ffs_epfile_aio_read,
+        .write =        new_sync_write,
+        .read =         new_sync_read,
+        .write_iter =   ffs_epfile_write_iter,
+        .read_iter =    ffs_epfile_read_iter,
         .release =      ffs_epfile_release,
         .unlocked_ioctl =       ffs_epfile_ioctl,
 };
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index db49ec4c748e..200f9a584064 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -74,6 +74,8 @@ MODULE_DESCRIPTION (DRIVER_DESC);
 MODULE_AUTHOR ("David Brownell");
 MODULE_LICENSE ("GPL");
 
+static int ep_open(struct inode *, struct file *);
+
 
 /*----------------------------------------------------------------------*/
 
@@ -283,14 +285,15 @@ static void epio_complete (struct usb_ep *ep, struct usb_request *req)
  * still need dev->lock to use epdata->ep.
  */
 static int
-get_ready_ep (unsigned f_flags, struct ep_data *epdata)
+get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 {
         int     val;
 
         if (f_flags & O_NONBLOCK) {
                 if (!mutex_trylock(&epdata->lock))
                         goto nonblock;
-                if (epdata->state != STATE_EP_ENABLED) {
+                if (epdata->state != STATE_EP_ENABLED &&
+                    (!is_write || epdata->state != STATE_EP_READY)) {
                         mutex_unlock(&epdata->lock);
 nonblock:
                         val = -EAGAIN;
@@ -305,18 +308,20 @@ nonblock:
 
         switch (epdata->state) {
         case STATE_EP_ENABLED:
+                return 0;
+        case STATE_EP_READY:                    /* not configured yet */
+                if (is_write)
+                        return 0;
+                // FALLTHRU
+        case STATE_EP_UNBOUND:                  /* clean disconnect */
                 break;
         // case STATE_EP_DISABLED:              /* "can't happen" */
-        // case STATE_EP_READY:                 /* "can't happen" */
         default:                                /* error! */
                 pr_debug ("%s: ep %p not available, state %d\n",
                                 shortname, epdata, epdata->state);
-                // FALLTHROUGH
-        case STATE_EP_UNBOUND:                  /* clean disconnect */
-                val = -ENODEV;
-                mutex_unlock(&epdata->lock);
         }
-        return val;
+        mutex_unlock(&epdata->lock);
+        return -ENODEV;
 }
 
 static ssize_t
@@ -363,97 +368,6 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len)
         return value;
 }
 
-
-/* handle a synchronous OUT bulk/intr/iso transfer */
-static ssize_t
-ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
-{
-        struct ep_data          *data = fd->private_data;
-        void                    *kbuf;
-        ssize_t                 value;
-
-        if ((value = get_ready_ep (fd->f_flags, data)) < 0)
-                return value;
-
-        /* halt any endpoint by doing a "wrong direction" i/o call */
-        if (usb_endpoint_dir_in(&data->desc)) {
-                if (usb_endpoint_xfer_isoc(&data->desc)) {
-                        mutex_unlock(&data->lock);
-                        return -EINVAL;
-                }
-                DBG (data->dev, "%s halt\n", data->name);
-                spin_lock_irq (&data->dev->lock);
-                if (likely (data->ep != NULL))
-                        usb_ep_set_halt (data->ep);
-                spin_unlock_irq (&data->dev->lock);
-                mutex_unlock(&data->lock);
-                return -EBADMSG;
-        }
-
-        /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
-
-        value = -ENOMEM;
-        kbuf = kmalloc (len, GFP_KERNEL);
-        if (unlikely (!kbuf))
-                goto free1;
-
-        value = ep_io (data, kbuf, len);
-        VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
-                data->name, len, (int) value);
-        if (value >= 0 && copy_to_user (buf, kbuf, value))
-                value = -EFAULT;
-
-free1:
-        mutex_unlock(&data->lock);
-        kfree (kbuf);
-        return value;
-}
-
-/* handle a synchronous IN bulk/intr/iso transfer */
-static ssize_t
-ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
-{
-        struct ep_data          *data = fd->private_data;
-        void                    *kbuf;
-        ssize_t                 value;
-
-        if ((value = get_ready_ep (fd->f_flags, data)) < 0)
-                return value;
-
-        /* halt any endpoint by doing a "wrong direction" i/o call */
-        if (!usb_endpoint_dir_in(&data->desc)) {
-                if (usb_endpoint_xfer_isoc(&data->desc)) {
-                        mutex_unlock(&data->lock);
-                        return -EINVAL;
-                }
-                DBG (data->dev, "%s halt\n", data->name);
-                spin_lock_irq (&data->dev->lock);
-                if (likely (data->ep != NULL))
-                        usb_ep_set_halt (data->ep);
-                spin_unlock_irq (&data->dev->lock);
-                mutex_unlock(&data->lock);
-                return -EBADMSG;
-        }
-
-        /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
-
-        value = -ENOMEM;
-        kbuf = memdup_user(buf, len);
-        if (IS_ERR(kbuf)) {
-                value = PTR_ERR(kbuf);
-                kbuf = NULL;
-                goto free1;
-        }
-
-        value = ep_io (data, kbuf, len);
-        VDEBUG (data->dev, "%s write %zu IN, status %d\n",
-                data->name, len, (int) value);
-free1:
-        mutex_unlock(&data->lock);
-        kfree (kbuf);
-        return value;
-}
-
 static int
 ep_release (struct inode *inode, struct file *fd)
 {
@@ -481,7 +395,7 @@ static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
         struct ep_data          *data = fd->private_data;
         int                     status;
 
-        if ((status = get_ready_ep (fd->f_flags, data)) < 0)
+        if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
                 return status;
 
         spin_lock_irq (&data->dev->lock);
@@ -517,8 +431,8 @@ struct kiocb_priv {
         struct mm_struct        *mm;
         struct work_struct      work;
         void                    *buf;
-        const struct iovec      *iv;
-        unsigned long           nr_segs;
+        struct iov_iter         to;
+        const void              *to_free;
         unsigned                actual;
 };
 
@@ -541,35 +455,6 @@ static int ep_aio_cancel(struct kiocb *iocb)
         return value;
 }
 
-static ssize_t ep_copy_to_user(struct kiocb_priv *priv)
-{
-        ssize_t                 len, total;
-        void                    *to_copy;
-        int                     i;
-
-        /* copy stuff into user buffers */
-        total = priv->actual;
-        len = 0;
-        to_copy = priv->buf;
-        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, to_copy, this)) {
-                        if (len == 0)
-                                len = -EFAULT;
-                        break;
-                }
-
-                total -= this;
-                len += this;
-                to_copy += this;
-                if (total == 0)
-                        break;
-        }
-
-        return len;
-}
-
 static void ep_user_copy_worker(struct work_struct *work)
 {
         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
@@ -578,13 +463,16 @@ static void ep_user_copy_worker(struct work_struct *work)
         size_t ret;
 
         use_mm(mm);
-        ret = ep_copy_to_user(priv);
+        ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
         unuse_mm(mm);
+        if (!ret)
+                ret = -EFAULT;
 
         /* completing the iocb can drop the ctx and mm, don't touch mm after */
         aio_complete(iocb, ret, ret);
 
         kfree(priv->buf);
+        kfree(priv->to_free);
         kfree(priv);
 }
 
@@ -603,8 +491,9 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
          * don't need to copy anything to userspace, so we can
          * complete the aio request immediately.
          */
-        if (priv->iv == NULL || unlikely(req->actual == 0)) {
+        if (priv->to_free == NULL || unlikely(req->actual == 0)) {
                 kfree(req->buf);
+                kfree(priv->to_free);
                 kfree(priv);
                 iocb->private = NULL;
                 /* aio_complete() reports bytes-transferred _and_ faults */
@@ -618,6 +507,7 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 
                 priv->buf = req->buf;
                 priv->actual = req->actual;
+                INIT_WORK(&priv->work, ep_user_copy_worker);
                 schedule_work(&priv->work);
         }
         spin_unlock(&epdata->dev->lock);
@@ -626,38 +516,17 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *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
-)
+static ssize_t ep_aio(struct kiocb *iocb,
+                      struct kiocb_priv *priv,
+                      struct ep_data *epdata,
+                      char *buf,
+                      size_t len)
 {
-        struct kiocb_priv       *priv;
-        struct usb_request      *req;
-        ssize_t                 value;
+        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->iocb = iocb;
-        priv->iv = iv;
-        priv->nr_segs = nr_segs;
-        INIT_WORK(&priv->work, ep_user_copy_worker);
-
-        value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
-        if (unlikely(value < 0)) {
-                kfree(priv);
-                goto fail;
-        }
 
         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
         get_ep(epdata);
@@ -669,75 +538,154 @@ fail:
          * 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);
+        value = -ENODEV;
+        if (unlikely(epdata->ep))
+                goto fail;
 
-        mutex_unlock(&epdata->lock);
+        req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
+        value = -ENOMEM;
+        if (unlikely(!req))
+                goto fail;
 
-        if (unlikely(value)) {
-                kfree(priv);
-                put_ep(epdata);
-        } else
-                value = -EIOCBQUEUED;
+        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);
+                goto fail;
+        }
+        spin_unlock_irq(&epdata->dev->lock);
+        return -EIOCBQUEUED;
+
+fail:
+        spin_unlock_irq(&epdata->dev->lock);
+        kfree(priv->to_free);
+        kfree(priv);
+        put_ep(epdata);
         return value;
 }
 
 static ssize_t
-ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
-                unsigned long nr_segs, loff_t o)
+ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-        struct ep_data          *epdata = iocb->ki_filp->private_data;
-        char                    *buf;
+        struct file *file = iocb->ki_filp;
+        struct ep_data *epdata = file->private_data;
+        size_t len = iov_iter_count(to);
+        ssize_t value;
+        char *buf;
 
-        if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
-                return -EINVAL;
+        if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
+                return value;
 
-        buf = kmalloc(iocb->ki_nbytes, GFP_KERNEL);
-        if (unlikely(!buf))
-                return -ENOMEM;
+        /* halt any endpoint by doing a "wrong direction" i/o call */
+        if (usb_endpoint_dir_in(&epdata->desc)) {
+                if (usb_endpoint_xfer_isoc(&epdata->desc) ||
+                    !is_sync_kiocb(iocb)) {
+                        mutex_unlock(&epdata->lock);
+                        return -EINVAL;
+                }
+                DBG (epdata->dev, "%s halt\n", epdata->name);
+                spin_lock_irq(&epdata->dev->lock);
+                if (likely(epdata->ep != NULL))
+                        usb_ep_set_halt(epdata->ep);
+                spin_unlock_irq(&epdata->dev->lock);
+                mutex_unlock(&epdata->lock);
+                return -EBADMSG;
+        }
 
-        return ep_aio_rwtail(iocb, buf, iocb->ki_nbytes, epdata, iov, nr_segs);
+        buf = kmalloc(len, GFP_KERNEL);
+        if (unlikely(!buf)) {
+                mutex_unlock(&epdata->lock);
+                return -ENOMEM;
+        }
+        if (is_sync_kiocb(iocb)) {
+                value = ep_io(epdata, buf, len);
+                if (value >= 0 && copy_to_iter(buf, value, to))
+                        value = -EFAULT;
+        } else {
+                struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
+                value = -ENOMEM;
+                if (!priv)
+                        goto fail;
+                priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
+                if (!priv->to_free) {
+                        kfree(priv);
+                        goto fail;
+                }
+                value = ep_aio(iocb, priv, epdata, buf, len);
+                if (value == -EIOCBQUEUED)
+                        buf = NULL;
+        }
+fail:
+        kfree(buf);
+        mutex_unlock(&epdata->lock);
+        return value;
 }
 
+static ssize_t ep_config(struct ep_data *, const char *, size_t);
+
 static ssize_t
-ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
-                unsigned long nr_segs, loff_t o)
+ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-        struct ep_data          *epdata = iocb->ki_filp->private_data;
-        char                    *buf;
-        size_t                  len = 0;
-        int                     i = 0;
+        struct file *file = iocb->ki_filp;
+        struct ep_data *epdata = file->private_data;
+        size_t len = iov_iter_count(from);
+        bool configured;
+        ssize_t value;
+        char *buf;
+
+        if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
+                return value;
 
-        if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
-                return -EINVAL;
+        configured = epdata->state == STATE_EP_ENABLED;
 
-        buf = kmalloc(iocb->ki_nbytes, GFP_KERNEL);
-        if (unlikely(!buf))
+        /* halt any endpoint by doing a "wrong direction" i/o call */
+        if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
+                if (usb_endpoint_xfer_isoc(&epdata->desc) ||
+                    !is_sync_kiocb(iocb)) {
+                        mutex_unlock(&epdata->lock);
+                        return -EINVAL;
+                }
+                DBG (epdata->dev, "%s halt\n", epdata->name);
+                spin_lock_irq(&epdata->dev->lock);
+                if (likely(epdata->ep != NULL))
+                        usb_ep_set_halt(epdata->ep);
+                spin_unlock_irq(&epdata->dev->lock);
+                mutex_unlock(&epdata->lock);
+                return -EBADMSG;
+        }
+
+        buf = kmalloc(len, GFP_KERNEL);
+        if (unlikely(!buf)) {
+                mutex_unlock(&epdata->lock);
                 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;
+        if (unlikely(copy_from_iter(buf, len, from) != len)) {
+                value = -EFAULT;
+                goto out;
+        }
+
+        if (unlikely(!configured)) {
+                value = ep_config(epdata, buf, len);
+        } else if (is_sync_kiocb(iocb)) {
+                value = ep_io(epdata, buf, len);
+        } else {
+                struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
+                value = -ENOMEM;
+                if (priv) {
+                        value = ep_aio(iocb, priv, epdata, buf, len);
+                        if (value == -EIOCBQUEUED)
+                                buf = NULL;
                 }
-                len += iov[i].iov_len;
         }
-        return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
+out:
+        kfree(buf);
+        mutex_unlock(&epdata->lock);
+        return value;
 }
 
 /*----------------------------------------------------------------------*/
@@ -745,15 +693,15 @@ ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 /* used after endpoint configuration */
 static const struct file_operations ep_io_operations = {
         .owner =        THIS_MODULE,
-        .llseek =       no_llseek,
 
-        .read =         ep_read,
-        .write =        ep_write,
-        .unlocked_ioctl = ep_ioctl,
+        .open =         ep_open,
         .release =      ep_release,
-
-        .aio_read =     ep_aio_read,
-        .aio_write =    ep_aio_write,
+        .llseek =       no_llseek,
+        .read =         new_sync_read,
+        .write =        new_sync_write,
+        .unlocked_ioctl = ep_ioctl,
+        .read_iter =    ep_read_iter,
+        .write_iter =   ep_write_iter,
 };
 
 /* ENDPOINT INITIALIZATION
@@ -770,17 +718,12 @@ static const struct file_operations ep_io_operations = {
  * speed descriptor, then optional high speed descriptor.
  */
 static ssize_t
-ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
+ep_config (struct ep_data *data, const char *buf, size_t len)
 {
-        struct ep_data          *data = fd->private_data;
         struct usb_ep           *ep;
         u32                     tag;
         int                     value, length = len;
 
-        value = mutex_lock_interruptible(&data->lock);
-        if (value < 0)
-                return value;
-
         if (data->state != STATE_EP_READY) {
                 value = -EL2HLT;
                 goto fail;
@@ -791,9 +734,7 @@ ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
                 goto fail0;
 
         /* we might need to change message format someday */
-        if (copy_from_user (&tag, buf, 4)) {
-                goto fail1;
-        }
+        memcpy(&tag, buf, 4);
         if (tag != 1) {
                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
                 goto fail0;
@@ -806,19 +747,15 @@ ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
          */
 
         /* full/low speed descriptor, then high speed */
-        if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
-                goto fail1;
-        }
+        memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
                 goto fail0;
         if (len != USB_DT_ENDPOINT_SIZE) {
                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
                         goto fail0;
-                if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
-                                        USB_DT_ENDPOINT_SIZE)) {
-                        goto fail1;
-                }
+                memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
+                        USB_DT_ENDPOINT_SIZE);
                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
                                 || data->hs_desc.bDescriptorType
                                         != USB_DT_ENDPOINT) {
@@ -840,24 +777,20 @@ ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
         case USB_SPEED_LOW:
         case USB_SPEED_FULL:
                 ep->desc = &data->desc;
-                value = usb_ep_enable(ep);
-                if (value == 0)
-                        data->state = STATE_EP_ENABLED;
                 break;
         case USB_SPEED_HIGH:
                 /* fails if caller didn't provide that descriptor... */
                 ep->desc = &data->hs_desc;
-                value = usb_ep_enable(ep);
-                if (value == 0)
-                        data->state = STATE_EP_ENABLED;
                 break;
         default:
                 DBG(data->dev, "unconnected, %s init abandoned\n",
                                 data->name);
                 value = -EINVAL;
+                goto gone;
         }
+        value = usb_ep_enable(ep);
         if (value == 0) {
-                fd->f_op = &ep_io_operations;
+                data->state = STATE_EP_ENABLED;
                 value = length;
         }
 gone:
@@ -867,14 +800,10 @@ fail:
                 data->desc.bDescriptorType = 0;
                 data->hs_desc.bDescriptorType = 0;
         }
-        mutex_unlock(&data->lock);
         return value;
 fail0:
         value = -EINVAL;
         goto fail;
-fail1:
-        value = -EFAULT;
-        goto fail;
 }
 
 static int
@@ -902,15 +831,6 @@ ep_open (struct inode *inode, struct file *fd)
         return value;
 }
 
-/* used before endpoint configuration */
-static const struct file_operations ep_config_operations = {
-        .llseek =       no_llseek,
-
-        .open =         ep_open,
-        .write =        ep_config,
-        .release =      ep_release,
-};
-
 /*----------------------------------------------------------------------*/
 
 /* EP0 IMPLEMENTATION can be partly in userspace.
@@ -989,6 +909,10 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
         enum ep0_state                  state;
 
         spin_lock_irq (&dev->lock);
+        if (dev->state <= STATE_DEV_OPENED) {
+                retval = -EINVAL;
+                goto done;
+        }
 
         /* report fd mode change before acting on it */
         if (dev->setup_abort) {
@@ -1187,8 +1111,6 @@ ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
         struct dev_data         *dev = fd->private_data;
         ssize_t                 retval = -ESRCH;
 
-        spin_lock_irq (&dev->lock);
-
         /* report fd mode change before acting on it */
         if (dev->setup_abort) {
                 dev->setup_abort = 0;
@@ -1234,7 +1156,6 @@ ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
         } else
                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
 
-        spin_unlock_irq (&dev->lock);
         return retval;
 }
 
@@ -1281,6 +1202,9 @@ ep0_poll (struct file *fd, poll_table *wait)
        struct dev_data         *dev = fd->private_data;
        int                     mask = 0;
 
+        if (dev->state <= STATE_DEV_OPENED)
+                return DEFAULT_POLLMASK;
+
        poll_wait(fd, &dev->wait, wait);
 
        spin_lock_irq (&dev->lock);
@@ -1316,19 +1240,6 @@ static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
         return ret;
 }
 
-/* used after device configuration */
-static const struct file_operations ep0_io_operations = {
-        .owner =        THIS_MODULE,
-        .llseek =       no_llseek,
-
-        .read =         ep0_read,
-        .write =        ep0_write,
-        .fasync =       ep0_fasync,
-        .poll =         ep0_poll,
-        .unlocked_ioctl =       dev_ioctl,
-        .release =      dev_release,
-};
-
 /*----------------------------------------------------------------------*/
 
 /* The in-kernel gadget driver handles most ep0 issues, in particular
@@ -1650,7 +1561,7 @@ static int activate_ep_files (struct dev_data *dev)
                         goto enomem1;
 
                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
-                                data, &ep_config_operations);
+                                data, &ep_io_operations);
                 if (!data->dentry)
                         goto enomem2;
                 list_add_tail (&data->epfiles, &dev->epfiles);
@@ -1852,6 +1763,14 @@ dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
         u32                     tag;
         char                    *kbuf;
 
+        spin_lock_irq(&dev->lock);
+        if (dev->state > STATE_DEV_OPENED) {
+                value = ep0_write(fd, buf, len, ptr);
+                spin_unlock_irq(&dev->lock);
+                return value;
+        }
+        spin_unlock_irq(&dev->lock);
+
         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
                 return -EINVAL;
 
@@ -1925,7 +1844,6 @@ dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
                  * on, they can work ... except in cleanup paths that
                  * kick in after the ep0 descriptor is closed.
                  */
-                fd->f_op = &ep0_io_operations;
                 value = len;
         }
         return value;
@@ -1956,12 +1874,14 @@ dev_open (struct inode *inode, struct file *fd)
         return value;
 }
 
-static const struct file_operations dev_init_operations = {
+static const struct file_operations ep0_operations = {
         .llseek =       no_llseek,
 
         .open =         dev_open,
+        .read =         ep0_read,
         .write =        dev_config,
         .fasync =       ep0_fasync,
+        .poll =         ep0_poll,
         .unlocked_ioctl = dev_ioctl,
         .release =      dev_release,
 };
@@ -2077,7 +1997,7 @@ gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
                 goto Enomem;
 
         dev->sb = sb;
-        dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &dev_init_operations);
+        dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
         if (!dev->dentry) {
                 put_dev(dev);
                 goto Enomem;
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 07a022641996..71880299ed48 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -98,6 +98,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
                         size_t maxsize, size_t *start);
 int iov_iter_npages(const struct iov_iter *i, int maxpages);
 
+const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
+
 static inline size_t iov_iter_count(struct iov_iter *i)
 {
         return i->count;
diff --git a/lib/Makefile b/lib/Makefile
index 87eb3bffc283..58f74d2dd396 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -24,7 +24,7 @@ obj-y	+= lockref.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
          bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
-         gcd.o lcm.o list_sort.o uuid.o flex_array.o clz_ctz.o \
+         gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \
          bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
          percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o
 obj-y += string_helpers.o
diff --git a/mm/iov_iter.c b/lib/iov_iter.c
index 827732047da1..9d96e283520c 100644
--- a/mm/iov_iter.c
+++ b/lib/iov_iter.c
@@ -751,3 +751,18 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
         return npages;
 }
 EXPORT_SYMBOL(iov_iter_npages);
+
+const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
+{
+        *new = *old;
+        if (new->type & ITER_BVEC)
+                return new->bvec = kmemdup(new->bvec,
+                                    new->nr_segs * sizeof(struct bio_vec),
+                                    flags);
+        else
+                /* iovec and kvec have identical layout */
+                return new->iov = kmemdup(new->iov,
+                                   new->nr_segs * sizeof(struct iovec),
+                                   flags);
+}
+EXPORT_SYMBOL(dup_iter);
diff --git a/mm/Makefile b/mm/Makefile
index 3c1caa2693bd..15dbe9903c27 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -21,7 +21,7 @@ obj-y			:= filemap.o mempool.o oom_kill.o \
                            mm_init.o mmu_context.o percpu.o slab_common.o \
                            compaction.o vmacache.o \
                            interval_tree.o list_lru.o workingset.o \
-                           iov_iter.o debug.o $(mmu-y)
+                           debug.o $(mmu-y)
 
 obj-y += init-mm.o