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Commit 2d533a92 authored by Denis Bolotin's avatar Denis Bolotin Committed by David S. Miller
Browse files

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: default avatarDenis Bolotin <dbolotin@marvell.com>
Signed-off-by: default avatarAriel Elior <aelior@marvell.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8c468e8

include/linux/qed/qed_chain.h

+31 −0
Original line number Diff line number Diff line
@@ -663,6 +663,37 @@ static inline void *qed_chain_get_last_elem(struct qed_chain *p_chain) 
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