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Commit e5b251a2 authored by Roland Dreier's avatar Roland Dreier
Browse files

[IB] mthca: Avoid SRQ free WQE list corruption 



Fix wqe_to_link() to use a structure field that we know is definitely
always unused for receive work requests, so that it really avoids the
free list corruption bug that the comment claims it does.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 7162a3e0

drivers/infiniband/hw/mthca/mthca_srq.c

+7 −6
Original line number Diff line number Diff line
@@ -75,15 +75,16 @@ static void *get_wqe(struct mthca_srq *srq, int n) 


/*

 * Return a pointer to the location within a WQE that we're using as a

 * link when the WQE is in the free list.  We use an offset of 4

 * because in the Tavor case, posting a WQE may overwrite the first

 * four bytes of the previous WQE.  The offset avoids corrupting our

 * free list if the WQE has already completed and been put on the free

 * list when we post the next WQE.

 * link when the WQE is in the free list.  We use the imm field

 * because in the Tavor case, posting a WQE may overwrite the next

 * segment of the previous WQE, but a receive WQE will never touch the

 * imm field.  This avoids corrupting our free list if the previous

 * WQE has already completed and been put on the free list when we

 * post the next WQE.

 */

static inline int *wqe_to_link(void *wqe)

{

	return (int *) (wqe + 4);

	return (int *) (wqe + offsetof(struct mthca_next_seg, imm));

}



static void mthca_tavor_init_srq_context(struct mthca_dev *dev,