Commit 97dd1abd authored by Alexander Lobakin's avatar Alexander Lobakin Committed by David S. Miller
Browse files

net: qed: fix left elements count calculation 



qed_chain_get_element_left{,_u32} returned 0 when the difference
between producer and consumer page count was equal to the total
page count.
Fix this by conditional expanding of producer value (vs
unconditional). This allowed to eliminate normalizaton against
total page count, which was the cause of this bug.

Misc: replace open-coded constants with common defines.

Fixes: a91eb52a ("qed: Revisit chain implementation")
Signed-off-by: default avatarAlexander Lobakin <alobakin@marvell.com>
Signed-off-by: default avatarIgor Russkikh <irusskikh@marvell.com>
Signed-off-by: default avatarMichal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b4730ae6

include/linux/qed/qed_chain.h

+16 −10
Original line number Diff line number Diff line
@@ -207,28 +207,34 @@ static inline u32 qed_chain_get_cons_idx_u32(struct qed_chain *p_chain) 


static inline u16 qed_chain_get_elem_left(struct qed_chain *p_chain)

{

	u16 elem_per_page = p_chain->elem_per_page;

	u32 prod = p_chain->u.chain16.prod_idx;

	u32 cons = p_chain->u.chain16.cons_idx;

	u16 used;



	used = (u16) (((u32)0x10000 +

		       (u32)p_chain->u.chain16.prod_idx) -

		      (u32)p_chain->u.chain16.cons_idx);

	if (prod < cons)

		prod += (u32)U16_MAX + 1;



	used = (u16)(prod - cons);

	if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)

		used -= p_chain->u.chain16.prod_idx / p_chain->elem_per_page -

		    p_chain->u.chain16.cons_idx / p_chain->elem_per_page;

		used -= prod / elem_per_page - cons / elem_per_page;



	return (u16)(p_chain->capacity - used);

}



static inline u32 qed_chain_get_elem_left_u32(struct qed_chain *p_chain)

{

	u16 elem_per_page = p_chain->elem_per_page;

	u64 prod = p_chain->u.chain32.prod_idx;

	u64 cons = p_chain->u.chain32.cons_idx;

	u32 used;



	used = (u32) (((u64)0x100000000ULL +

		       (u64)p_chain->u.chain32.prod_idx) -

		      (u64)p_chain->u.chain32.cons_idx);

	if (prod < cons)

		prod += (u64)U32_MAX + 1;



	used = (u32)(prod - cons);

	if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)

		used -= p_chain->u.chain32.prod_idx / p_chain->elem_per_page -

		    p_chain->u.chain32.cons_idx / p_chain->elem_per_page;

		used -= (u32)(prod / elem_per_page - cons / elem_per_page);



	return p_chain->capacity - used;

}

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