From d2fd4d395abb5c5695fb754c82fc7c20f8537852 Mon Sep 17 00:00:00 2001 From: Andrey Utkin Date: Fri, 11 Jul 2014 15:38:30 +0100 Subject: [PATCH] staging: comedi: ni_atmio16d.c: remove pointless condition The issue was discovered with static analysis and has two instances in this file. The code looks like this if (x < 65536000) { ... } else if (x < 655360000) { ... } else if (x <= 0xffffffff /* 6553600000 */) { ... } else if (x <= 0xffffffff /* 65536000000 */) { ... } The meaning of this block is to select appropriate clock frequency for interval timer basing on "x", which is amount of time. Notes: 1. That last condition matches previous one - that's the issue. 2. Decimal numbers in comments don't match hex numbers in expressions. But in first case the numbers have same order, while in the second case the hex number is the same, and the decimal one is 10 times bigger. 3. Actually type of "x" is "unsigned int", so its exact upper limit is not obviously known. 4. There's no "else" block. So it makes sense to make an "else" block from last "else if" case. The code inside the block seems correct for such usage. [ Actually, get rid of the final "else if" case and change the next-to-last "else if" case to an "else" as the upper limit of "x" _is_ known to be 0xffffffff (UINT_MAX), which is less than 6553600000 -- Ian ] Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=79871 Reported-by: David Binderman Signed-off-by: Andrey Utkin Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/ni_atmio16d.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_atmio16d.c b/drivers/staging/comedi/drivers/ni_atmio16d.c index 6ad27f50..b1b4744 100644 --- a/drivers/staging/comedi/drivers/ni_atmio16d.c +++ b/drivers/staging/comedi/drivers/ni_atmio16d.c @@ -335,12 +335,9 @@ static int atmio16d_ai_cmd(struct comedi_device *dev, } else if (cmd->convert_arg < 655360000) { base_clock = CLOCK_100_KHZ; timer = cmd->convert_arg / 10000; - } else if (cmd->convert_arg <= 0xffffffff /* 6553600000 */) { + } else /* cmd->convert_arg < 6553600000 */ { base_clock = CLOCK_10_KHZ; timer = cmd->convert_arg / 100000; - } else if (cmd->convert_arg <= 0xffffffff /* 65536000000 */) { - base_clock = CLOCK_1_KHZ; - timer = cmd->convert_arg / 1000000; } outw(0xFF03, dev->iobase + AM9513A_COM_REG); outw(base_clock, dev->iobase + AM9513A_DATA_REG); @@ -403,12 +400,9 @@ static int atmio16d_ai_cmd(struct comedi_device *dev, } else if (cmd->scan_begin_arg < 655360000) { base_clock = CLOCK_100_KHZ; timer = cmd->scan_begin_arg / 10000; - } else if (cmd->scan_begin_arg < 0xffffffff /* 6553600000 */) { + } else /* cmd->scan_begin_arg < 6553600000 */ { base_clock = CLOCK_10_KHZ; timer = cmd->scan_begin_arg / 100000; - } else if (cmd->scan_begin_arg < 0xffffffff /* 65536000000 */) { - base_clock = CLOCK_1_KHZ; - timer = cmd->scan_begin_arg / 1000000; } outw(0xFF02, dev->iobase + AM9513A_COM_REG); outw(base_clock, dev->iobase + AM9513A_DATA_REG); -- 2.7.4