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Revert "bcache: fix fifo index swapping condition in journal_pin_cmp()"

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Coly says:

"Guoju Fang talked to me today, he told me this change was unnecessary
and I was over-thought.

Then I realize fifo_idx() uses a mask to handle the array index overflow
condition, so the index swap in journal_pin_cmp() won't happen. And yes,
Guoju and Kent are correct.

Since you already applied this patch, can you please to remove this
patch from your for-next branch? This single patch does not break
thing, but it is unecessary at this moment."

This reverts commit c0e0954e90.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2019-11-18 08:35:47 -07:00
parent 97ab474c2d
commit 00b89892c8
2 changed files with 4 additions and 26 deletions
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26
drivers/md/bcache/btree.c
View File

@ -528,32 +528,6 @@ static void btree_node_write_work(struct work_struct *w)
mutex_unlock(&b->write_lock);
}
/* return true if journal pin 'l' is newer than 'r' */
static bool journal_pin_cmp(struct cache_set *c,
atomic_t *l,
atomic_t *r)
{
int l_idx, r_idx, f_idx, b_idx;
bool ret = false;
l_idx = fifo_idx(&(c)->journal.pin, (l));
r_idx = fifo_idx(&(c)->journal.pin, (r));
f_idx = (c)->journal.pin.front;
b_idx = (c)->journal.pin.back;
if (l_idx > r_idx)
ret = true;
/* in case fifo back pointer is swapped */
if (b_idx < f_idx) {
if (l_idx <= b_idx && r_idx >= f_idx)
ret = true;
else if (l_idx >= f_idx && r_idx <= b_idx)
ret = false;
}
return ret;
}
static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
{
struct bset *i = btree_bset_last(b);

4
drivers/md/bcache/journal.h
View File

@ -157,6 +157,10 @@ struct journal_device {
};
#define BTREE_FLUSH_NR 8
#define journal_pin_cmp(c, l, r) \
(fifo_idx(&(c)->journal.pin, (l)) > fifo_idx(&(c)->journal.pin, (r)))
#define JOURNAL_PIN 20000
#define journal_full(j) \