bcachefs: Use one buffer for sorting whiteouts

We're not really supposed to allocate from the same mempool more than
once.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 6a658f2c63283810e40d2e453ec48f9c15da5cf9..90fc31037bbf2bb97777d08789b2ee6d86de3460 100644 (file)
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -118,30 +118,32 @@ static void sort_bkey_ptrs(const struct btree *bt,
 
 static void bch2_sort_whiteouts(struct bch_fs *c, struct btree *b)
 {
-       struct bkey_packed *new_whiteouts, **whiteout_ptrs, *k;
-       bool used_mempool1 = false, used_mempool2 = false;
-       unsigned order, i, nr = 0;
+       struct bkey_packed *new_whiteouts, **ptrs, **ptrs_end, *k;
+       bool used_mempool = false;
+       unsigned order;
 
        if (!b->whiteout_u64s)
                return;
 
        order = get_order(b->whiteout_u64s * sizeof(u64));
 
-       new_whiteouts = btree_bounce_alloc(c, order, &used_mempool1);
-       whiteout_ptrs = btree_bounce_alloc(c, order, &used_mempool2);
+       new_whiteouts = btree_bounce_alloc(c, order, &used_mempool);
+
+       ptrs = ptrs_end = ((void *) new_whiteouts + (PAGE_SIZE << order));
 
        for (k = unwritten_whiteouts_start(c, b);
             k != unwritten_whiteouts_end(c, b);
             k = bkey_next(k))
-               whiteout_ptrs[nr++] = k;
+               *--ptrs = k;
 
-       sort_bkey_ptrs(b, whiteout_ptrs, nr);
+       sort_bkey_ptrs(b, ptrs, ptrs_end - ptrs);
 
        k = new_whiteouts;
 
-       for (i = 0; i < nr; i++) {
-               bkey_copy(k, whiteout_ptrs[i]);
+       while (ptrs != ptrs_end) {
+               bkey_copy(k, *ptrs);
                k = bkey_next(k);
+               ptrs++;
        }
 
        verify_no_dups(b, new_whiteouts,
@@ -150,8 +152,7 @@ static void bch2_sort_whiteouts(struct bch_fs *c, struct btree *b)
        memcpy_u64s(unwritten_whiteouts_start(c, b),
                    new_whiteouts, b->whiteout_u64s);
 
-       btree_bounce_free(c, order, used_mempool2, whiteout_ptrs);
-       btree_bounce_free(c, order, used_mempool1, new_whiteouts);
+       btree_bounce_free(c, order, used_mempool, new_whiteouts);
 }
 
 static bool should_compact_bset(struct btree *b, struct bset_tree *t,