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Commit c11da83b authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

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: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c728cc88

drivers/isdn/divert/divert_procfs.c

+4 −3
Original line number Diff line number Diff line
@@ -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 */

drivers/isdn/hysdn/hysdn_proclog.c

+4 −3
Original line number Diff line number Diff line
@@ -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 */