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Subject[PATCH v3 1/8] rtl2832: use 64-bit arithmetic instead of 32-bit in rtl2832_set_frontend
Add suffix ULL to constant 7 in order to give the compiler complete
information about the proper arithmetic to use. Notice that this
constant is used in a context that expects an expression of type
u64 (64 bits, unsigned).

The expression dev->pdata->clk * 7 is currently being evaluated
using 32-bit arithmetic.

Addresses-Coverity-ID: 1271223 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Changes in v2:
- Update subject and changelog to better reflect the proposed code changes.
- Add suffix ULL to constant instead of casting a variable.

Changes in v3:
- Mention the specific Coverity report in the commit message.

drivers/media/dvb-frontends/rtl2832.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index 94bf5b7..fa3b816 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -498,7 +498,7 @@ static int rtl2832_set_frontend(struct dvb_frontend *fe)
* RSAMP_RATIO = floor(CrystalFreqHz * 7 * pow(2, 22)
* / ConstWithBandwidthMode)
*/
- num = dev->pdata->clk * 7;
+ num = dev->pdata->clk * 7ULL;
num *= 0x400000;
num = div_u64(num, bw_mode);
resamp_ratio = num & 0x3ffffff;
@@ -511,7 +511,7 @@ static int rtl2832_set_frontend(struct dvb_frontend *fe)
* / (CrystalFreqHz * 7))
*/
num = bw_mode << 20;
- num2 = dev->pdata->clk * 7;
+ num2 = dev->pdata->clk * 7ULL;
num = div_u64(num, num2);
num = -num;
cfreq_off_ratio = num & 0xfffff;
--
2.7.4
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