From d4461a602cf39c59f32817162539f4e723621865 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 3 Mar 2015 08:39:34 +0000 Subject: [PATCH] gadgetfs: get rid of flipping ->f_op in ep_config() Final methods start with get_ready_ep(), which will fail unless we have ->state == STATE_EP_ENABLED. So they'd be failing just fine until that first write() anyway. Let's do the following: * get_ready_ep() gets a new argument - true when called from ep_write_iter(), false otherwise. * make it quiet when it finds STATE_EP_READY (no printk, that is; the case won't be impossible after that change). * when that new argument is true, treat STATE_EP_READY the same way as STATE_EP_ENABLED (i.e. return zero and do not unlock). * in ep_write_iter(), after success of get_ready_ep() turn if (!usb_endpoint_dir_in(&epdata->desc)) { into if (epdata->state == STATE_EP_ENABLED && !usb_endpoint_dir_in(&epdata->desc)) { - that logics only applies after config. * have ep_config() take kernel-side buffer (i.e. use memcpy() instead of copy_from_user() in there) and in the "let's call ep_io or ep_aio" (again, in ep_write_iter()) add "... or ep_config() in case it's not configured yet" Signed-off-by: Al Viro --- drivers/usb/gadget/legacy/inode.c | 90 +++++++++++++------------------ 1 file changed, 37 insertions(+), 53 deletions(-) diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index b825edcbf387..c0e25320a3c4 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 @@ -390,7 +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); @@ -572,7 +577,7 @@ ep_read_iter(struct kiocb *iocb, struct iov_iter *to) ssize_t value; char *buf; - if ((value = get_ready_ep(file->f_flags, epdata)) < 0) + if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0) return value; /* halt any endpoint by doing a "wrong direction" i/o call */ @@ -620,20 +625,25 @@ fail: return value; } +static ssize_t ep_config(struct ep_data *, const char *, size_t); + static ssize_t ep_write_iter(struct kiocb *iocb, struct iov_iter *from) { 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)) < 0) + if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0) return value; + configured = epdata->state == STATE_EP_ENABLED; + /* halt any endpoint by doing a "wrong direction" i/o call */ - if (!usb_endpoint_dir_in(&epdata->desc)) { + if (configured && !usb_endpoint_dir_in(&epdata->desc)) { if (usb_endpoint_xfer_isoc(&epdata->desc) || !is_sync_kiocb(iocb)) { mutex_unlock(&epdata->lock); @@ -659,7 +669,9 @@ ep_write_iter(struct kiocb *iocb, struct iov_iter *from) goto out; } - if (is_sync_kiocb(iocb)) { + 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); @@ -681,13 +693,13 @@ out: /* used after endpoint configuration */ static const struct file_operations ep_io_operations = { .owner = THIS_MODULE, - .llseek = no_llseek, + .open = ep_open, + .release = ep_release, + .llseek = no_llseek, .read = new_sync_read, .write = new_sync_write, .unlocked_ioctl = ep_ioctl, - .release = ep_release, - .read_iter = ep_read_iter, .write_iter = ep_write_iter, }; @@ -706,17 +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; @@ -727,9 +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; @@ -742,19 +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) { @@ -776,24 +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: @@ -803,14 +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 @@ -838,15 +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. @@ -1586,7 +1570,7 @@ 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); -- 2.34.1