Messages in this thread Patch in this message |  | | | Date | Sat, 16 Aug 2008 00:15:16 +0200 (CEST) | | From | Stefan Richter <> | | Subject | [RFC patch 3/3] ieee1394: raw1394: make write() thread-safe |
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Application programs should use a libraw1394 handle only in a single thread. The raw1394 driver was apparently relying on this, because it did nothing to protect its fi->state variable from corruption due to concurrent accesses.
We now serialize the fi->state accesses. This affects the write() path. We re-use the state_mutex which was introduced to protect fi->iso_state accesses in the ioctl() path. These paths and accesses are independent of each other, hence separate mutexes could be used. But I don't see much benefit in that.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> --- drivers/ieee1394/raw1394.c | 4 ++++ 1 file changed, 4 insertions(+) Index: linux/drivers/ieee1394/raw1394.c =================================================================== --- linux.orig/drivers/ieee1394/raw1394.c +++ linux/drivers/ieee1394/raw1394.c @@ -2268,6 +2268,8 @@ static ssize_t raw1394_write(struct file return -EFAULT; } + mutex_lock(&fi->state_mutex); + switch (fi->state) { case opened: retval = state_opened(fi, req); @@ -2282,6 +2284,8 @@ static ssize_t raw1394_write(struct file break; } + mutex_unlock(&fi->state_mutex); + if (retval < 0) { free_pending_request(req); } else { -- Stefan Richter -=====-==--- =--- =---- http://arcgraph.de/sr/
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