From 10963ea1bd966ba46a46178c4d6abcdf3c23538d Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sat, 16 Aug 2008 00:11:48 +0200 Subject: ieee1394: raw1394: replace BKL by local mutex, make ioctl() and mmap() thread-safe This removes the last usage of the Big Kernel Lock from the ieee1394 stack, i.e. from raw1394's (unlocked_)ioctl and compat_ioctl. The ioctl()s don't need to take the BKL, but they need to be serialized per struct file *. In particular, accesses to ->iso_state need to be serial. We simply use a blocking mutex for this purpose because libraw1394 does not use O_NONBLOCK. In practice, there is no lock contention anyway because most if not all libraw1394 clients use a libraw1394 handle only in a single thread. mmap() also accesses ->iso_state. Until now this was unprotected against concurrent changes by ioctls. Fix this bug while we are at it. Signed-off-by: Stefan Richter --- drivers/ieee1394/raw1394-private.h | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/ieee1394/raw1394-private.h') diff --git a/drivers/ieee1394/raw1394-private.h b/drivers/ieee1394/raw1394-private.h index a06aaad5b448..7a225a405987 100644 --- a/drivers/ieee1394/raw1394-private.h +++ b/drivers/ieee1394/raw1394-private.h @@ -22,6 +22,7 @@ enum raw1394_iso_state { RAW1394_ISO_INACTIVE = 0, struct file_info { struct list_head list; + struct mutex state_mutex; enum { opened, initialized, connected } state; unsigned int protocol_version; -- cgit v1.2.3