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| author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-08-16 00:15:16 +0200 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-10-15 22:21:08 +0200 |
| commit | f22e52b89e036fd12b9374212da8b5d4a447bd1e (patch) | |
| tree | 84e8cb2fca80197dc1b2afee85d2c46fd8446af0 /drivers/ieee1394/raw1394.c | |
| parent | ieee1394: raw1394: narrow down the state_mutex protected region (diff) | |
| download | linux-f22e52b89e036fd12b9374212da8b5d4a447bd1e.tar.xz linux-f22e52b89e036fd12b9374212da8b5d4a447bd1e.zip | |
ieee1394: raw1394: make write() thread-safe
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>
Diffstat (limited to 'drivers/ieee1394/raw1394.c')
| -rw-r--r-- | drivers/ieee1394/raw1394.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/ieee1394/raw1394.c b/drivers/ieee1394/raw1394.c index d1594427601f..2cf4ae75beca 100644 --- a/drivers/ieee1394/raw1394.c +++ b/drivers/ieee1394/raw1394.c @@ -2268,6 +2268,8 @@ static ssize_t raw1394_write(struct file *file, const char __user * buffer, 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 *file, const char __user * buffer, break; } + mutex_unlock(&fi->state_mutex); + if (retval < 0) { free_pending_request(req); } else { |