[PATCH] md: make the code more readable in the for-loop

Tiezhu Yang
2016-05-08T13:28:26Z

This patch modifies raid1.c, raid10.c and raid5.c
to make the code more readable in the for-loop
and also fixes the scripts/checkpatch.pl error:
ERROR: trailing statements should be on next line.

Signed-off-by: Tiezhu Yang <kernelpatch@126.com>
---
drivers/md/raid1.c | 6 +++---
drivers/md/raid10.c | 2 +-
drivers/md/raid5.c | 59 +++++++++++++++++++++++++++--------------------------
3 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a7f2b9c..760de56 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -109,7 +109,7 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
/*
* Allocate bios : 1 for reading, n-1 for writing
*/
- for (j = pi->raid_disks ; j-- ; ) {
+ for (j = pi->raid_disks - 1; j >= 0; j--) {
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
@@ -166,7 +166,7 @@ static void r1buf_pool_free(void *__r1_bio, void *data)
struct r1bio *r1bio = __r1_bio;

for (i = 0; i < RESYNC_PAGES; i++)
- for (j = pi->raid_disks; j-- ;) {
+ for (j = pi->raid_disks - 1; j >= 0; j--) {
if (j == 0 ||
r1bio->bios[j]->bi_io_vec[i].bv_page !=
r1bio->bios[0]->bi_io_vec[i].bv_page)
@@ -1976,7 +1976,7 @@ static void process_checks(struct r1bio *r1_bio)
sbio->bi_error = 0;

if (!error) {
- for (j = vcnt; j-- ; ) {
+ for (j = vcnt - 1; j >= 0; j--) {
struct page *p, *s;
p = pbio->bi_io_vec[j].bv_page;
s = sbio->bi_io_vec[j].bv_page;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 84e24e6..52f1e07 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -157,7 +157,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
/*
* Allocate bios.
*/
- for (j = nalloc ; j-- ; ) {
+ for (j = nalloc - 1; j >= 0; j--) {
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4d31b23..db978ab 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -536,7 +536,7 @@ retry:
stripe_set_idx(sector, conf, previous, sh);
sh->state = 0;

- for (i = sh->disks; i--; ) {
+ for (i = sh->disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];

if (dev->toread || dev->read || dev->towrite || dev->written ||
@@ -890,7 +890,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)

if (r5l_write_stripe(conf->log, sh) == 0)
return;
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
int rw;
int replace_only = 0;
struct bio *bi, *rbi;
@@ -1175,7 +1175,7 @@ static void ops_complete_biofill(void *stripe_head_ref)
(unsigned long long)sh->sector);

/* clear completed biofills */
- for (i = sh->disks; i--; ) {
+ for (i = sh->disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];

/* acknowledge completion of a biofill operation */
@@ -1216,7 +1216,7 @@ static void ops_run_biofill(struct stripe_head *sh)
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);

- for (i = sh->disks; i--; ) {
+ for (i = sh->disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (test_bit(R5_Wantfill, &dev->flags)) {
struct bio *rbi;
@@ -1307,7 +1307,7 @@ ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
__func__, (unsigned long long)sh->sector, target);
BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));

- for (i = disks; i--; )
+ for (i = disks - 1; i >= 0; i--)
if (i != target)
xor_srcs[count++] = sh->dev[i].page;

@@ -1407,7 +1407,7 @@ ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
} else {
/* Compute any data- or p-drive using XOR */
count = 0;
- for (i = disks; i-- ; ) {
+ for (i = disks - 1; i >= 0; i--) {
if (i == target || i == qd_idx)
continue;
blocks[count++] = sh->dev[i].page;
@@ -1492,7 +1492,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
data_target = target;

count = 0;
- for (i = disks; i-- ; ) {
+ for (i = disks - 1; i >= 0; i--) {
if (i == data_target || i == qd_idx)
continue;
blocks[count++] = sh->dev[i].page;
@@ -1554,7 +1554,7 @@ ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
/* Only process blocks that are known to be uptodate */
if (test_bit(R5_Wantdrain, &dev->flags))
@@ -1598,7 +1598,7 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev;
struct bio *chosen;

@@ -1663,13 +1663,13 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
discard |= test_bit(R5_Discard, &sh->dev[i].flags);
}

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];

if (dev->written || i == pd_idx || i == qd_idx) {
@@ -1734,14 +1734,14 @@ again:
if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
prexor = 1;
xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (head_sh->dev[i].written)
xor_srcs[count++] = dev->page;
}
} else {
xor_dest = sh->dev[pd_idx].page;
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (i != pd_idx)
xor_srcs[count++] = dev->page;
@@ -1872,7 +1872,7 @@ static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
count = 0;
xor_dest = sh->dev[pd_idx].page;
xor_srcs[count++] = xor_dest;
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
if (i == pd_idx || i == qd_idx)
continue;
xor_srcs[count++] = sh->dev[i].page;
@@ -1970,7 +1970,7 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
}

if (overlap_clear && !sh->batch_head)
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (test_and_clear_bit(R5_Overlap, &dev->flags))
wake_up(&sh->raid_conf->wait_for_overlap);
@@ -2861,7 +2861,7 @@ schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,

if (rcw) {

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];

if (dev->towrite) {
@@ -2897,7 +2897,7 @@ schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
(!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));

- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (i == pd_idx || i == qd_idx)
continue;
@@ -3072,7 +3072,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
{
int i;
BUG_ON(sh->batch_head);
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct bio *bi;
int bitmap_end = 0;

@@ -3386,7 +3386,7 @@ static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
* do it if failed >= 2
*/
int other;
- for (other = disks; other--; ) {
+ for (other = disks - 1; other >= 0; other--) {
if (other == disk_idx)
continue;
if (!test_bit(R5_UPTODATE,
@@ -3433,7 +3433,7 @@ static void handle_stripe_fill(struct stripe_head *sh,
*/
if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
!sh->reconstruct_state)
- for (i = disks; i--; )
+ for (i = disks - 1; i >= 0; i--)
if (fetch_block(sh, s, i, disks))
break;
set_bit(STRIPE_HANDLE, &sh->state);
@@ -3455,7 +3455,7 @@ static void handle_stripe_clean_event(struct r5conf *conf,
struct stripe_head *head_sh = sh;
bool do_endio = false;

- for (i = disks; i--; )
+ for (i = disks - 1; i >= 0; i--)
if (sh->dev[i].written) {
dev = &sh->dev[i];
if (!test_bit(R5_LOCKED, &dev->flags) &&
@@ -3573,7 +3573,8 @@ static void handle_stripe_dirtying(struct r5conf *conf,
pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
conf->rmw_level, (unsigned long long)recovery_cp,
(unsigned long long)sh->sector);
- } else for (i = disks; i--; ) {
+ } else
+ for (i = disks - 1; i >= 0; i--) {
/* would I have to read this buffer for read_modify_write */
struct r5dev *dev = &sh->dev[i];
if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
@@ -3606,7 +3607,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
blk_add_trace_msg(conf->mddev->queue,
"raid5 rmw %llu %d",
(unsigned long long)sh->sector, rmw);
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
@@ -3631,7 +3632,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
/* want reconstruct write, but need to get some data */
int qread =0;
rcw = 0;
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (!test_bit(R5_OVERWRITE, &dev->flags) &&
i != sh->pd_idx && i != sh->qd_idx &&
@@ -4021,7 +4022,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)

/* Now to look around and see what can be done */
rcu_read_lock();
- for (i=disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct md_rdev *rdev;
sector_t first_bad;
int bad_sectors;
@@ -4391,7 +4392,7 @@ static void handle_stripe(struct stripe_head *sh)
BUG_ON(sh->qd_idx >= 0 &&
!test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
!test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct r5dev *dev = &sh->dev[i];
if (test_bit(R5_LOCKED, &dev->flags) &&
(i == sh->pd_idx || i == sh->qd_idx ||
@@ -4539,7 +4540,7 @@ static void handle_stripe(struct stripe_head *sh)

sh->reconstruct_state = reconstruct_state_idle;
clear_bit(STRIPE_EXPANDING, &sh->state);
- for (i = conf->raid_disks; i--; ) {
+ for (i = conf->raid_disks - 1; i >= 0; i--) {
set_bit(R5_Wantwrite, &sh->dev[i].flags);
set_bit(R5_LOCKED, &sh->dev[i].flags);
s.locked++;
@@ -4579,7 +4580,7 @@ finish:
}

if (s.handle_bad_blocks)
- for (i = disks; i--; ) {
+ for (i = disks - 1; i >= 0; i--) {
struct md_rdev *rdev;
struct r5dev *dev = &sh->dev[i];
if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
@@ -5486,7 +5487,7 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
/* If any of this stripe is beyond the end of the old
* array, then we need to zero those blocks
*/
- for (j=sh->disks; j--;) {
+ for (j = sh->disks - 1; j >= 0; j--) {
sector_t s;
if (j == sh->pd_idx)
continue;
--
1.8.3.1