adulau/aha
1
0
Fork 0
mirror of https://github.com/adulau/aha.git synced 2024-12-28 11:46:19 +00:00
Code Issues Projects Releases Packages Wiki Activity

USB: CDC WDM driver doesn't support non-blocking reads

Browse source 
support for O_NONBLOCK in read and write path
by simply not waiting for data in read or availability
of the write urb in write but returning -EAGAIN

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Tested-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum 2009-09-09 10:12:48 +02:00 committed by Greg Kroah-Hartman
parent ce60c48871
commit 7f1dc313d0
1 changed files with 24 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
drivers/usb/class/cdc-wdm.c
View file

@ -313,8 +313,13 @@ static ssize_t wdm_write
r = usb_autopm_get_interface(desc->intf); r = usb_autopm_get_interface(desc->intf);
if (r < 0) if (r < 0)
goto outnp; goto outnp;
r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
&desc->flags)); if (!file->f_flags && O_NONBLOCK)
r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
&desc->flags));
else
if (test_bit(WDM_IN_USE, &desc->flags))
r = -EAGAIN;
if (r < 0) if (r < 0)
goto out; goto out;
@ -377,7 +382,7 @@ outnl:
static ssize_t wdm_read static ssize_t wdm_read
(struct file *file, char __user *buffer, size_t count, loff_t *ppos) (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{ {
int rv, cntr; int rv, cntr = 0;
int i = 0; int i = 0;
struct wdm_device *desc = file->private_data; struct wdm_device *desc = file->private_data;
@ -389,10 +394,23 @@ static ssize_t wdm_read
if (desc->length == 0) { if (desc->length == 0) {
desc->read = 0; desc->read = 0;
retry: retry:
if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
rv = -ENODEV;
goto err;
}
i++; i++;
rv = wait_event_interruptible(desc->wait, if (file->f_flags & O_NONBLOCK) {
test_bit(WDM_READ, &desc->flags)); if (!test_bit(WDM_READ, &desc->flags)) {
rv = cntr ? cntr : -EAGAIN;
goto err;
}
rv = 0;
} else {
rv = wait_event_interruptible(desc->wait,
test_bit(WDM_READ, &desc->flags));
}
/* may have happened while we slept */
if (test_bit(WDM_DISCONNECTING, &desc->flags)) { if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
rv = -ENODEV; rv = -ENODEV;
goto err; goto err;
@ -448,7 +466,7 @@ retry:
err: err:
mutex_unlock(&desc->rlock); mutex_unlock(&desc->rlock);
if (rv < 0) if (rv < 0 && rv != -EAGAIN)
dev_err(&desc->intf->dev, "wdm_read: exit error\n"); dev_err(&desc->intf->dev, "wdm_read: exit error\n");
return rv; return rv;
} }