[PATCH] USB speedtouch: eliminate ATM open/close races

From: Duncan Sands (baldrick@wanadoo.fr)
Date: Tue Mar 25 2003 - 04:31:50 EST


The list of open vccs is modified by open/close, and traversed by the
receive tasklet. This is the last race I know of in this driver.

speedtch.c | 20 ++++++++++++++++++--
1 files changed, 18 insertions(+), 2 deletions(-)

diff -Nru a/drivers/usb/misc/speedtch.c b/drivers/usb/misc/speedtch.c
--- a/drivers/usb/misc/speedtch.c Tue Mar 25 10:27:35 2003
+++ b/drivers/usb/misc/speedtch.c Tue Mar 25 10:27:35 2003
@@ -933,11 +933,17 @@
         if (vcc->qos.aal != ATM_AAL5)
                 return -EINVAL;
 
- if (udsl_find_vcc (instance, vpi, vci))
+ down (&instance->serialize); /* vs self, udsl_atm_close */
+
+ if (udsl_find_vcc (instance, vpi, vci)) {
+ up (&instance->serialize);
                 return -EADDRINUSE;
+ }
 
- if (!(new = kmalloc (sizeof (struct udsl_vcc_data), GFP_KERNEL)))
+ if (!(new = kmalloc (sizeof (struct udsl_vcc_data), GFP_KERNEL))) {
+ up (&instance->serialize);
                 return -ENOMEM;
+ }
 
         memset (new, 0, sizeof (struct udsl_vcc_data));
         new->vcc = vcc;
@@ -949,12 +955,16 @@
         vcc->vpi = vpi;
         vcc->vci = vci;
 
+ tasklet_disable (&instance->receive_tasklet);
         list_add (&new->list, &instance->vcc_list);
+ tasklet_enable (&instance->receive_tasklet);
 
         set_bit (ATM_VF_ADDR, &vcc->flags);
         set_bit (ATM_VF_PARTIAL, &vcc->flags);
         set_bit (ATM_VF_READY, &vcc->flags);
 
+ up (&instance->serialize);
+
         dbg ("Allocated new SARLib vcc 0x%p with vpi %d vci %d", new, vpi, vci);
 
         MOD_INC_USE_COUNT;
@@ -983,7 +993,11 @@
 
         udsl_cancel_send (instance, vcc);
 
+ down (&instance->serialize); /* vs self, udsl_atm_open */
+
+ tasklet_disable (&instance->receive_tasklet);
         list_del (&vcc_data->list);
+ tasklet_enable (&instance->receive_tasklet);
 
         if (vcc_data->reasBuffer)
                 kfree_skb (vcc_data->reasBuffer);
@@ -997,6 +1011,8 @@
         clear_bit (ATM_VF_READY, &vcc->flags);
         clear_bit (ATM_VF_PARTIAL, &vcc->flags);
         clear_bit (ATM_VF_ADDR, &vcc->flags);
+
+ up (&instance->serialize);
 
         MOD_DEC_USE_COUNT;
 

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This archive was generated by hypermail 2b29 : Mon Mar 31 2003 - 22:00:19 EST