isdn: divert, hysdn: fix interruptible_sleep_on race

These two drivers use identical code for their procfs status
file handling, which contains a small race against status
data becoming available while reading the file.

This uses wait_event_interruptible instead to fix this
particular race and eventually get rid of all sleep_on
instances. There seems to be another race involving
multiple concurrent readers of the same procfs file, which
I don't try to fix here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/divert/divert_procfs.c b/drivers/isdn/divert/divert_procfs.c
index fb4f1ba..1c5dc34 100644 (file)
--- a/drivers/isdn/divert/divert_procfs.c
+++ b/drivers/isdn/divert/divert_procfs.c
@@ -86,12 +86,13 @@ isdn_divert_read(struct file *file, char __user *buf, size_t count, loff_t *off)
        struct divert_info *inf;
        int len;
 
-       if (!*((struct divert_info **) file->private_data)) {
+       if (!(inf = *((struct divert_info **) file->private_data))) {
                if (file->f_flags & O_NONBLOCK)
                        return -EAGAIN;
-               interruptible_sleep_on(&(rd_queue));
+               wait_event_interruptible(rd_queue, (inf =
+                       *((struct divert_info **) file->private_data)));
        }
-       if (!(inf = *((struct divert_info **) file->private_data)))
+       if (!inf)
                return (0);
 
        inf->usage_cnt--;       /* new usage count */

diff --git a/drivers/isdn/hysdn/hysdn_proclog.c b/drivers/isdn/hysdn/hysdn_proclog.c
index b61e8d5..7b5fd8f 100644 (file)
--- a/drivers/isdn/hysdn/hysdn_proclog.c
+++ b/drivers/isdn/hysdn/hysdn_proclog.c
@@ -175,14 +175,15 @@ hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t *off)
        int len;
        hysdn_card *card = PDE_DATA(file_inode(file));
 
-       if (!*((struct log_data **) file->private_data)) {
+       if (!(inf = *((struct log_data **) file->private_data))) {
                struct procdata *pd = card->proclog;
                if (file->f_flags & O_NONBLOCK)
                        return (-EAGAIN);
 
-               interruptible_sleep_on(&(pd->rd_queue));
+               wait_event_interruptible(pd->rd_queue, (inf =
+                               *((struct log_data **) file->private_data)));
        }
-       if (!(inf = *((struct log_data **) file->private_data)))
+       if (!inf)
                return (0);
 
        inf->usage_cnt--;       /* new usage count */