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authorOliver Neukum <oliver@neukum.org>2009-09-09 10:23:35 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2009-09-23 06:46:40 -0700
commit798199867385417ba6494472e39c016e3340758c (patch)
tree0be421533a966075130254d41ba0ae7ea0a25e71 /drivers/usb
parente7389cc9a7ff7c6e760e741c81a751c834f7d145 (diff)
USB: make usb-skeleton honor O_NONBLOCK in write path
usb:usb-skeleton: honor O_NONBLOCK in write path nonblocking writes are allowed by using down_trylock if necessary to reserve an URB Signed-off-by: Oliver Neukum <oliver@neukum.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/usb-skeleton.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 5ffa3e24685..768fda9064e 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -399,9 +399,16 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
goto exit;
/* limit the number of URBs in flight to stop a user from using up all RAM */
- if (down_interruptible(&dev->limit_sem)) {
- retval = -ERESTARTSYS;
- goto exit;
+ if (!file->f_flags & O_NONBLOCK) {
+ if (down_interruptible(&dev->limit_sem)) {
+ retval = -ERESTARTSYS;
+ goto exit;
+ }
+ } else {
+ if (down_trylock(&dev->limit_sem)) {
+ retval = -EAGAIN;
+ goto exit;
+ }
}
spin_lock_irq(&dev->err_lock);