hartmannathan commented on a change in pull request #5718:
URL: https://github.com/apache/incubator-nuttx/pull/5718#discussion_r824860390
##########
File path: drivers/can/can.c
##########
@@ -407,46 +406,48 @@ static int can_open(FAR struct file *filep)
* for this device, then perform hardware initialization.
*/
- if (list_is_empty(&dev->cd_readers))
+ caninfo("ocount: %u\n", dev->cd_crefs);
+
+ if (dev->cd_crefs >= 255)
{
- caninfo("ocount: %d\n", 0);
+ /* Limit to no more than 255 opens */
+ ret = -EMFILE;
+ goto errout;
+ }
+ else
+ {
flags = enter_critical_section();
- ret = dev_setup(dev);
- if (ret >= 0)
+
+ if (dev->cd_crefs == 0)
{
- /* Mark the FIFOs empty */
+ ret = dev_setup(dev);
+ if (ret == OK)
+ {
+ /* Mark the FIFOs empty */
- dev->cd_xmit.tx_head = 0;
- dev->cd_xmit.tx_queue = 0;
- dev->cd_xmit.tx_tail = 0;
+ dev->cd_xmit.tx_head = 0;
+ dev->cd_xmit.tx_queue = 0;
+ dev->cd_xmit.tx_tail = 0;
- /* Finally, Enable the CAN RX interrupt */
+ /* Finally, Enable the CAN RX interrupt */
- dev_rxint(dev, true);
+ dev_rxint(dev, true);
+ }
}
- list_add_head(&dev->cd_readers,
- (FAR struct list_node *)init_can_reader(filep));
-
- leave_critical_section(flags);
- }
- else
- {
- tmp = list_length(&dev->cd_readers);
- caninfo("ocount: %d\n", tmp);
-
- if (tmp >= 255)
+ if (ret == OK)
Review comment:
This ret may be the one from either can_takesem() or dev_setup(). Not
saying that's a problem, just saying.
##########
File path: drivers/can/can.c
##########
@@ -407,46 +406,48 @@ static int can_open(FAR struct file *filep)
* for this device, then perform hardware initialization.
*/
- if (list_is_empty(&dev->cd_readers))
+ caninfo("ocount: %u\n", dev->cd_crefs);
+
+ if (dev->cd_crefs >= 255)
{
- caninfo("ocount: %d\n", 0);
+ /* Limit to no more than 255 opens */
Review comment:
LGTM; we were missing this before and could rollover if too many opens.
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