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-rw-r--r--mm/page-writeback.c32
1 files changed, 27 insertions, 5 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3e19b87049..c9af72f292 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -415,13 +415,20 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
else
bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE;
- if (bg_thresh >= thresh)
- bg_thresh = thresh / 2;
tsk = current;
if (rt_task(tsk)) {
bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32;
thresh += thresh / 4 + global_wb_domain.dirty_limit / 32;
}
+ /*
+ * Dirty throttling logic assumes the limits in page units fit into
+ * 32-bits. This gives 16TB dirty limits max which is hopefully enough.
+ */
+ if (thresh > UINT_MAX)
+ thresh = UINT_MAX;
+ /* This makes sure bg_thresh is within 32-bits as well */
+ if (bg_thresh >= thresh)
+ bg_thresh = thresh / 2;
dtc->thresh = thresh;
dtc->bg_thresh = bg_thresh;
@@ -471,7 +478,11 @@ static unsigned long node_dirty_limit(struct pglist_data *pgdat)
if (rt_task(tsk))
dirty += dirty / 4;
- return dirty;
+ /*
+ * Dirty throttling logic assumes the limits in page units fit into
+ * 32-bits. This gives 16TB dirty limits max which is hopefully enough.
+ */
+ return min_t(unsigned long, dirty, UINT_MAX);
}
/**
@@ -508,10 +519,17 @@ static int dirty_background_bytes_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
+ unsigned long old_bytes = dirty_background_bytes;
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
- if (ret == 0 && write)
+ if (ret == 0 && write) {
+ if (DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE) >
+ UINT_MAX) {
+ dirty_background_bytes = old_bytes;
+ return -ERANGE;
+ }
dirty_background_ratio = 0;
+ }
return ret;
}
@@ -537,6 +555,10 @@ static int dirty_bytes_handler(struct ctl_table *table, int write,
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
if (ret == 0 && write && vm_dirty_bytes != old_bytes) {
+ if (DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE) > UINT_MAX) {
+ vm_dirty_bytes = old_bytes;
+ return -ERANGE;
+ }
writeback_set_ratelimit();
vm_dirty_ratio = 0;
}
@@ -1638,7 +1660,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need