4.14-stable review patch. If anyone has any objections, please let me know.
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From: Herbert Xu herbert@gondor.apana.org.au
[ Upstream commit 408f13ef358aa5ad56dc6230c2c7deb92cf462b1 ]
As it stands if a shrink is delayed because of an outstanding rehash, we will go into a rescheduling loop without ever doing the rehash.
This patch fixes this by still carrying out the rehash and then rescheduling so that we can shrink after the completion of the rehash should it still be necessary.
The return value of EEXIST captures this case and other cases (e.g., another thread expanded/rehashed the table at the same time) where we should still proceed with the rehash.
Fixes: da20420f83ea ("rhashtable: Add nested tables") Reported-by: Josh Elsasser jelsasser@appneta.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Tested-by: Josh Elsasser jelsasser@appneta.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/rhashtable.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -459,8 +459,12 @@ static void rht_deferred_worker(struct w else if (tbl->nest) err = rhashtable_rehash_alloc(ht, tbl, tbl->size);
- if (!err) - err = rhashtable_rehash_table(ht); + if (!err || err == -EEXIST) { + int nerr; + + nerr = rhashtable_rehash_table(ht); + err = err ?: nerr; + }
mutex_unlock(&ht->mutex);