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staging: comedi: comedi_bond: fix 'b_mask' calc in bonding_dio_insn_bits()

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'b_chans' may be a valud up to 32. 'b_mask' is an unsigned int and a left shift of
more than 31 bits has undefined behavior. Fix the calc so it works correctly with
a 'b_chans' of 32..

Reported-by: coverity (CID 1192244)
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2015-04-20 11:49:04 -07:00 committed by Greg Kroah-Hartman
parent 351f6689cc
commit b3ab6fbfd8
1 changed files with 2 additions and 1 deletions
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3
drivers/staging/comedi/drivers/comedi_bond.c
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@ -101,7 +101,8 @@ static int bonding_dio_insn_bits(struct comedi_device *dev,
b_chans = bdev->nchans - base_chan;
if (b_chans > n_left)
b_chans = n_left;
b_mask = (1U << b_chans) - 1;
b_mask = (b_chans < 32) ? ((1 << b_chans) - 1)
: 0xffffffff;
b_write_mask = (write_mask >> n_done) & b_mask;
b_data_bits = (data_bits >> n_done) & b_mask;
/* Read/Write the new digital lines. */