This allows users to make an ioctl call as the first action on a
connection. Ex, some functions might want to get endpoint size
before making any i/os.
Previously, calling ioctls before read/write would depending on the
timing of endpoints being enabled.
ESHUTDOWN is now a possible return value and ENODEV is not, so change
docs accordingly.
Signed-off-by: Jerry Zhang <zhangje...@google.com>
---
Changelog since v2:
- Updated doc to account for -ESHUTDOWN
Changelog since v1:
- Guarded against epfile->ep changing after taking lock
drivers/usb/gadget/function/f_fs.c | 93 +++++++++++++++++++++----------------
include/uapi/linux/usb/functionfs.h | 7 +--
2 files changed, 58 insertions(+), 42 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c
b/drivers/usb/gadget/function/f_fs.c
index a0085571824d..04425e6b457a 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1190,6 +1190,7 @@ static long ffs_epfile_ioctl(struct file *file, unsigned
code,
unsigned long value)
{
struct ffs_epfile *epfile = file->private_data;
+ struct ffs_ep *ep;
int ret;
ENTER();
@@ -1197,50 +1198,64 @@ static long ffs_epfile_ioctl(struct file *file,
unsigned code,
if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
return -ENODEV;
+ /* Wait for endpoint to be enabled */
+ ep = epfile->ep;
+ if (!ep) {
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
+ if (ret)
+ return -EINTR;
+ }
+
spin_lock_irq(&epfile->ffs->eps_lock);
- if (likely(epfile->ep)) {
- switch (code) {
- case FUNCTIONFS_FIFO_STATUS:
- ret = usb_ep_fifo_status(epfile->ep->ep);
- break;
- case FUNCTIONFS_FIFO_FLUSH:
- usb_ep_fifo_flush(epfile->ep->ep);
- ret = 0;
- break;
- case FUNCTIONFS_CLEAR_HALT:
- ret = usb_ep_clear_halt(epfile->ep->ep);
- break;
- case FUNCTIONFS_ENDPOINT_REVMAP:
- ret = epfile->ep->num;
- break;
- case FUNCTIONFS_ENDPOINT_DESC:
- {
- int desc_idx;
- struct usb_endpoint_descriptor *desc;
- switch (epfile->ffs->gadget->speed) {
- case USB_SPEED_SUPER:
- desc_idx = 2;
- break;
- case USB_SPEED_HIGH:
- desc_idx = 1;
- break;
- default:
- desc_idx = 0;
- }
- desc = epfile->ep->descs[desc_idx];
+ /* In the meantime, endpoint got disabled or changed. */
+ if (epfile->ep != ep) {
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+ return -ESHUTDOWN;
+ }
- spin_unlock_irq(&epfile->ffs->eps_lock);
- ret = copy_to_user((void *)value, desc, desc->bLength);
- if (ret)
- ret = -EFAULT;
- return ret;
- }
+ switch (code) {
+ case FUNCTIONFS_FIFO_STATUS:
+ ret = usb_ep_fifo_status(epfile->ep->ep);
+ break;
+ case FUNCTIONFS_FIFO_FLUSH:
+ usb_ep_fifo_flush(epfile->ep->ep);
+ ret = 0;
+ break;
+ case FUNCTIONFS_CLEAR_HALT:
+ ret = usb_ep_clear_halt(epfile->ep->ep);
+ break;
+ case FUNCTIONFS_ENDPOINT_REVMAP:
+ ret = epfile->ep->num;
+ break;
+ case FUNCTIONFS_ENDPOINT_DESC:
+ {
+ int desc_idx;
+ struct usb_endpoint_descriptor *desc;
+
+ switch (epfile->ffs->gadget->speed) {
+ case USB_SPEED_SUPER:
+ desc_idx = 2;
+ break;
+ case USB_SPEED_HIGH:
+ desc_idx = 1;
+ break;
default:
- ret = -ENOTTY;
+ desc_idx = 0;
}
- } else {
- ret = -ENODEV;
+ desc = epfile->ep->descs[desc_idx];
+
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+ ret = copy_to_user((void *)value, desc, desc->bLength);
+ if (ret)
+ ret = -EFAULT;
+ return ret;
+ }
+ default:
+ ret = -ENOTTY;
}
spin_unlock_irq(&epfile->ffs->eps_lock);
diff --git a/include/uapi/linux/usb/functionfs.h
b/include/uapi/linux/usb/functionfs.h
index b2a31a55a612..297bca230dd0 100644
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -275,13 +275,14 @@ struct usb_functionfs_event {
#define FUNCTIONFS_INTERFACE_REVMAP _IO('g', 128)
/*
- * Returns real bEndpointAddress of an endpoint. If function is not
- * active returns -ENODEV.
+ * Returns real bEndpointAddress of an endpoint. If endpoint shuts down
+ * during the call, returns -ESHUTDOWN.
*/
#define FUNCTIONFS_ENDPOINT_REVMAP _IO('g', 129)
/*
- * Returns endpoint descriptor. If function is not active returns -ENODEV.
+ * Returns endpoint descriptor. If endpoint shuts down during the call,
+ * returns -ESHUTDOWN.
*/
#define FUNCTIONFS_ENDPOINT_DESC _IOR('g', 130, \
struct usb_endpoint_descriptor)
--
2.12.2.816.g2cccc81164-goog
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