Pull timer fix from Thomas Gleixner: "One more fix from the timer departement: - Handle division of negative nanosecond values proper on 32bit. A recent cleanup wrecked the sign handling of the dividend and dropped the check for negative divisors" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Fix ktime_divns to do signed division
Unified · Split
| @@ -166,19 +166,34 @@ static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2) · 165 unmodified lines | ||
| 166 | 166 | } |
| 167 | 167 | |
| 168 | 168 | #if BITS_PER_LONG < 64 |
| 169 | −extern u64 __ktime_divns(const ktime_t kt, s64 div); | |
| 170 | −static inline u64 ktime_divns(const ktime_t kt, s64 div) | |
| 169 | +extern s64 __ktime_divns(const ktime_t kt, s64 div); | |
| 170 | +static inline s64 ktime_divns(const ktime_t kt, s64 div) | |
| 171 | 171 | { |
| 172 | + /* | |
| 173 | + * Negative divisors could cause an inf loop, | |
| 174 | + * so bug out here. | |
| 175 | + */ | |
| 176 | + BUG_ON(div < 0); | |
| 172 | 177 | if (__builtin_constant_p(div) && !(div >> 32)) { |
| 173 | − u64 ns = kt.tv64; | |
| 174 | − do_div(ns, div); | |
| 175 | − return ns; | |
| 178 | + s64 ns = kt.tv64; | |
| 179 | + u64 tmp = ns < 0 ? -ns : ns; | |
| 180 | + | |
| 181 | + do_div(tmp, div); | |
| 182 | + return ns < 0 ? -tmp : tmp; | |
| 176 | 183 | } else { |
| 177 | 184 | return __ktime_divns(kt, div); |
| 178 | 185 | } |
| 179 | 186 | } |
| 180 | 187 | #else /* BITS_PER_LONG < 64 */ |
| 181 | −# define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) | |
| 188 | +static inline s64 ktime_divns(const ktime_t kt, s64 div) | |
| 189 | +{ | |
| 190 | + /* | |
| 191 | + * 32-bit implementation cannot handle negative divisors, | |
| 192 | + * so catch them on 64bit as well. | |
| 193 | + */ | |
| 194 | + WARN_ON(div < 0); | |
| 195 | + return kt.tv64 / div; | |
| 196 | +} | |
| 182 | 197 | #endif |
| 183 | 198 | |
| 184 | 199 | static inline s64 ktime_to_us(const ktime_t kt) |
| @@ -266,21 +266,23 @@ lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) · 265 unmodified lines | ||
| 266 | 266 | /* |
| 267 | 267 | * Divide a ktime value by a nanosecond value |
| 268 | 268 | */ |
| 269 | −u64 __ktime_divns(const ktime_t kt, s64 div) | |
| 269 | +s64 __ktime_divns(const ktime_t kt, s64 div) | |
| 270 | 270 | { |
| 271 | − u64 dclc; | |
| 272 | 271 | int sft = 0; |
| 272 | + s64 dclc; | |
| 273 | + u64 tmp; | |
| 273 | 274 | |
| 274 | 275 | dclc = ktime_to_ns(kt); |
| 276 | + tmp = dclc < 0 ? -dclc : dclc; | |
| 277 | + | |
| 275 | 278 | /* Make sure the divisor is less than 2^32: */ |
| 276 | 279 | while (div >> 32) { |
| 277 | 280 | sft++; |
| 278 | 281 | div >>= 1; |
| 279 | 282 | } |
| 280 | − dclc >>= sft; | |
| 281 | − do_div(dclc, (unsigned long) div); | |
| 282 | − | |
| 283 | − return dclc; | |
| 283 | + tmp >>= sft; | |
| 284 | + do_div(tmp, (unsigned long) div); | |
| 285 | + return dclc < 0 ? -tmp : tmp; | |
| 284 | 286 | } |
| 285 | 287 | EXPORT_SYMBOL_GPL(__ktime_divns); |
| 286 | 288 | #endif /* BITS_PER_LONG >= 64 */ |