From 2d533a9287f2011632977e87ce2783f4c689c984 Mon Sep 17 00:00:00 2001 From: Denis Bolotin Date: Thu, 3 Jan 2019 12:02:39 +0200 Subject: [PATCH] qed: Fix qed_chain_set_prod() for PBL chains with non power of 2 page count In PBL chains with non power of 2 page count, the producer is not at the beginning of the chain when index is 0 after a wrap. Therefore, after the producer index wrap around, page index should be calculated more carefully. Signed-off-by: Denis Bolotin Signed-off-by: Ariel Elior Signed-off-by: David S. Miller --- include/linux/qed/qed_chain.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/include/linux/qed/qed_chain.h b/include/linux/qed/qed_chain.h index 59ddf9af909e..2dd0a9ed5b36 100644 --- a/include/linux/qed/qed_chain.h +++ b/include/linux/qed/qed_chain.h @@ -663,6 +663,37 @@ out: static inline void qed_chain_set_prod(struct qed_chain *p_chain, u32 prod_idx, void *p_prod_elem) { + if (p_chain->mode == QED_CHAIN_MODE_PBL) { + u32 cur_prod, page_mask, page_cnt, page_diff; + + cur_prod = is_chain_u16(p_chain) ? p_chain->u.chain16.prod_idx : + p_chain->u.chain32.prod_idx; + + /* Assume that number of elements in a page is power of 2 */ + page_mask = ~p_chain->elem_per_page_mask; + + /* Use "cur_prod - 1" and "prod_idx - 1" since producer index + * reaches the first element of next page before the page index + * is incremented. See qed_chain_produce(). + * Index wrap around is not a problem because the difference + * between current and given producer indices is always + * positive and lower than the chain's capacity. + */ + page_diff = (((cur_prod - 1) & page_mask) - + ((prod_idx - 1) & page_mask)) / + p_chain->elem_per_page; + + page_cnt = qed_chain_get_page_cnt(p_chain); + if (is_chain_u16(p_chain)) + p_chain->pbl.c.u16.prod_page_idx = + (p_chain->pbl.c.u16.prod_page_idx - + page_diff + page_cnt) % page_cnt; + else + p_chain->pbl.c.u32.prod_page_idx = + (p_chain->pbl.c.u32.prod_page_idx - + page_diff + page_cnt) % page_cnt; + } + if (is_chain_u16(p_chain)) p_chain->u.chain16.prod_idx = (u16) prod_idx; else -- 2.30.2