blkio-throttle: Fix link failure failure on i386

o Randy Dunlap reported following linux-next failure. This patch fixes it.

on i386:

blk-throttle.c:(.text+0x1abb8): undefined reference to `__udivdi3'
blk-throttle.c:(.text+0x1b1dc): undefined reference to `__udivdi3'

o bytes_per_second interface is 64bit and I was continuing to do 64 bit
  division even on 32bit platform without help of special macros/functions
  hence the failure.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 11713ed..a467002 100644 (file)
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -378,7 +378,8 @@ throtl_slice_used(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 static inline void
 throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 {
-       unsigned long nr_slices, bytes_trim, time_elapsed, io_trim;
+       unsigned long nr_slices, time_elapsed, io_trim;
+       u64 bytes_trim, tmp;
 
        BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw]));
 
@@ -396,8 +397,10 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 
        if (!nr_slices)
                return;
+       tmp = tg->bps[rw] * throtl_slice * nr_slices;
+       do_div(tmp, HZ);
+       bytes_trim = tmp;
 
-       bytes_trim = (tg->bps[rw] * throtl_slice * nr_slices)/HZ;
        io_trim = (tg->iops[rw] * throtl_slice * nr_slices)/HZ;
 
        if (!bytes_trim && !io_trim)
@@ -415,7 +418,7 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
 
        tg->slice_start[rw] += nr_slices * throtl_slice;
 
-       throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%lu io=%lu"
+       throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"
                        " start=%lu end=%lu jiffies=%lu",
                        rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,
                        tg->slice_start[rw], tg->slice_end[rw], jiffies);
@@ -462,7 +465,7 @@ static bool tg_with_in_bps_limit(struct throtl_data *td, struct throtl_grp *tg,
                struct bio *bio, unsigned long *wait)
 {
        bool rw = bio_data_dir(bio);
-       u64 bytes_allowed, extra_bytes;
+       u64 bytes_allowed, extra_bytes, tmp;
        unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;
 
        jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw];
@@ -473,8 +476,9 @@ static bool tg_with_in_bps_limit(struct throtl_data *td, struct throtl_grp *tg,
 
        jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice);
 
-       bytes_allowed = (tg->bps[rw] * jiffies_to_msecs(jiffy_elapsed_rnd))
-                               / MSEC_PER_SEC;
+       tmp = tg->bps[rw] * jiffies_to_msecs(jiffy_elapsed_rnd);
+       do_div(tmp, MSEC_PER_SEC);
+       bytes_allowed = tmp;
 
        if (tg->bytes_disp[rw] + bio->bi_size <= bytes_allowed) {
                if (wait)