[PATCHv5.1 3/5] usb: gadget: f_fs: remove loop from I/O function

[Michal Nazarewicz]

When endpoint changes (due to it being disabled or alt setting changed),
mimic the action as if the change happened after the request has been
queued, instead of retrying with the new endpoint.

Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
---
 drivers/usb/gadget/f_fs.c | 94 ++++++++++++++++++++---------------------------
 1 file changed, 40 insertions(+), 54 deletions(-)

Fixed checkpatch.pl issues pointed out by David.

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 0658908..6cb0b22 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -758,73 +758,59 @@ static ssize_t ffs_epfile_io(struct file *file,
 	ssize_t ret;
 	int halt;
 
-	goto first_try;
-	do {
-		spin_unlock_irq(&epfile->ffs->eps_lock);
-		mutex_unlock(&epfile->mutex);
+	/* Are we still active? */
+	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
+		ret = -ENODEV;
+		goto error;
+	}
 
-first_try:
-		/* Are we still active? */
-		if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
-			ret = -ENODEV;
+	/* Wait for endpoint to be enabled */
+	ep = epfile->ep;
+	if (!ep) {
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
 			goto error;
 		}
 
-		/* Wait for endpoint to be enabled */
-		ep = epfile->ep;
-		if (!ep) {
-			if (file->f_flags & O_NONBLOCK) {
-				ret = -EAGAIN;
-				goto error;
-			}
-
-			if (wait_event_interruptible(epfile->wait,
-						     (ep = epfile->ep))) {
-				ret = -EINTR;
-				goto error;
-			}
-		}
-
-		/* Do we halt? */
-		halt = !read == !epfile->in;
-		if (halt && epfile->isoc) {
-			ret = -EINVAL;
+		ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
+		if (ret) {
+			ret = -EINTR;
 			goto error;
 		}
+	}
 
-		/* Allocate & copy */
-		if (!halt && !data) {
-			data = kzalloc(len, GFP_KERNEL);
-			if (unlikely(!data))
-				return -ENOMEM;
+	/* Do we halt? */
+	halt = !read == !epfile->in;
+	if (halt && epfile->isoc) {
+		ret = -EINVAL;
+		goto error;
+	}
 
-			if (!read &&
-			    unlikely(__copy_from_user(data, buf, len))) {
-				ret = -EFAULT;
-				goto error;
-			}
-		}
+	/* Allocate & copy */
+	if (!halt) {
+		data = kmalloc(len, GFP_KERNEL);
+		if (unlikely(!data))
+			return -ENOMEM;
 
-		/* We will be using request */
-		ret = ffs_mutex_lock(&epfile->mutex,
-				     file->f_flags & O_NONBLOCK);
-		if (unlikely(ret))
+		if (!read && unlikely(copy_from_user(data, buf, len))) {
+			ret = -EFAULT;
 			goto error;
+		}
+	}
 
-		/*
-		 * We're called from user space, we can use _irq rather then
-		 * _irqsave
-		 */
-		spin_lock_irq(&epfile->ffs->eps_lock);
+	/* We will be using request */
+	ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
+	if (unlikely(ret))
+		goto error;
 
-		/*
-		 * While we were acquiring mutex endpoint got disabled
-		 * or changed?
-		 */
-	} while (unlikely(epfile->ep != ep));
+	spin_lock_irq(&epfile->ffs->eps_lock);
 
-	/* Halt */
-	if (unlikely(halt)) {
+	if (epfile->ep != ep) {
+		/* In the meantime, endpoint got disabled or changed. */
+		ret = -ESHUTDOWN;
+		spin_unlock_irq(&epfile->ffs->eps_lock);
+	} else if (halt) {
+		/* Halt */
 		if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 			usb_ep_set_halt(ep->ep);
 		spin_unlock_irq(&epfile->ffs->eps_lock);
-- 
1.8.4.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/