rhashtable: add schedule points

BugLink: https://bugs.launchpad.net/bugs/1836117
Rehashing and destroying large hash table takes a lot of time,
and happens in process context. It is safe to add cond_resched()
in rhashtable_rehash_table() and rhashtable_free_and_destroy()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit ae6da1f503abb5a5081f9f6c4a6881de97830f3e)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 2c83e280ac49fc24b4fc0d151862806d2af2766d..5bcd837ea82a8e527e3bb6b3948dd403e7f07822 100644 (file)
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -364,6 +364,7 @@ static int rhashtable_rehash_table(struct rhashtable *ht)
                err = rhashtable_rehash_chain(ht, old_hash);
                if (err)
                        return err;
+               cond_resched();
        }
 
        /* Publish the new table pointer. */
@@ -1074,6 +1075,7 @@ restart:
                for (i = 0; i < tbl->size; i++) {
                        struct rhash_head *pos, *next;
 
+                       cond_resched();
                        for (pos = rht_dereference(*rht_bucket(tbl, i), ht),
                             next = !rht_is_a_nulls(pos) ?
                                        rht_dereference(pos->next, ht) : NULL;