From: Oliver Neukum <[EMAIL PROTECTED]>
io_edgeport is using a global variable without locking.
This is _the_ classical race condition. This patch switches to atomic_t.
Signed-off-by: Oliver Neukum <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/serial/io_edgeport.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 6a26a2e..187fd42 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -212,7 +212,7 @@ static int debug;
static int low_latency = 1; /* tty low latency flag, on by default */
-static int CmdUrbs = 0; /* Number of outstanding Command Write
Urbs */
+static atomic_t CmdUrbs; /* Number of outstanding Command Write
Urbs */
/* local function prototypes */
@@ -779,8 +779,8 @@ static void edge_bulk_out_cmd_callback (struct urb *urb)
dbg("%s", __FUNCTION__);
- CmdUrbs--;
- dbg("%s - FREE URB %p (outstanding %d)", __FUNCTION__, urb, CmdUrbs);
+ atomic_dec(&CmdUrbs);
+ dbg("%s - FREE URB %p (outstanding %d)", __FUNCTION__, urb,
atomic_read(&CmdUrbs));
/* clean up the transfer buffer */
@@ -2317,8 +2317,8 @@ static int write_cmd_usb (struct edgeport_port
*edge_port, unsigned char *buffer
if (!urb)
return -ENOMEM;
- CmdUrbs++;
- dbg("%s - ALLOCATE URB %p (outstanding %d)", __FUNCTION__, urb,
CmdUrbs);
+ atomic_inc(&CmdUrbs);
+ dbg("%s - ALLOCATE URB %p (outstanding %d)", __FUNCTION__, urb,
atomic_read(&CmdUrbs));
usb_fill_bulk_urb (urb, edge_serial->serial->dev,
usb_sndbulkpipe(edge_serial->serial->dev,
edge_serial->bulk_out_endpoint),
@@ -2332,7 +2332,7 @@ static int write_cmd_usb (struct edgeport_port
*edge_port, unsigned char *buffer
dev_err(&edge_port->port->dev, "%s - usb_submit_urb(write
command) failed, status = %d\n", __FUNCTION__, status);
usb_kill_urb(urb);
usb_free_urb(urb);
- CmdUrbs--;
+ atomic_dec(&CmdUrbs);
return status;
}
@@ -3083,6 +3083,7 @@ static int __init edgeport_init(void)
retval = usb_register(&io_driver);
if (retval)
goto failed_usb_register;
+ atomic_set(&CmdUrbs, 0);
info(DRIVER_DESC " " DRIVER_VERSION);
return 0;
--
1.5.1.2
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