在 2024/8/23 1:08, Mikulas Patocka 写道: > > On Thu, 22 Aug 2024, Chen Yufan wrote: > >> Use time_after_eq macro instead of opening it for readability. >> >> Signed-off-by: Chen Yufan <chenyufan@xxxxxxxx> >> --- >> drivers/md/dm-writecache.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c >> index 7ce8847b3..548d4d37e 100644 >> --- a/drivers/md/dm-writecache.c >> +++ b/drivers/md/dm-writecache.c >> @@ -16,6 +16,7 @@ >> #include <linux/pfn_t.h> >> #include <linux/libnvdimm.h> >> #include <linux/delay.h> >> +#include <linux/jiffies.h> >> #include "dm-io-tracker.h" >> >> #define DM_MSG_PREFIX "writecache" >> @@ -1994,8 +1995,8 @@ static void writecache_writeback(struct work_struct *work) >> while (!list_empty(&wc->lru) && >> (wc->writeback_all || >> wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark || >> - (jiffies - container_of(wc->lru.prev, struct wc_entry, lru)->age >= >> - wc->max_age - wc->max_age / MAX_AGE_DIV))) { >> + (time_after_eq(jiffies, container_of(wc->lru.prev, struct wc_entry, lru)->age + >> + (wc->max_age - wc->max_age / MAX_AGE_DIV))))) { >> >> n_walked++; >> if (unlikely(n_walked > WRITEBACK_LATENCY) && >> -- >> 2.39.0 > I'm not sure about this. The old and new code is not really equivalent. > > Mikulas The code here is susceptible to overflow issues, and the time_*() macros can handle this. Chen >