From 7ef7f613c2b019d5454431f4ba4eab205baa5167 Mon Sep 17 00:00:00 2001 From: Adrian Chadd Date: Sun, 29 Jul 2012 08:52:32 +0000 Subject: [PATCH] Fix breakage introduced in r238824 - correctly calculate the descriptor wrapping. The previous code was only wrapping descriptor "block" boundaries rather than individual descriptors. It sounds equivalent but it isn't. r238824 changed the descriptor allocation to enforce that an individual descriptor doesn't wrap a 4KiB boundary rather than the whole block of descriptors. Eg, for TX descriptors, they're allocated in blocks of 10 descriptors for each ath_buf (for scatter/gather DMA.) --- sys/dev/ath/if_ath.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/sys/dev/ath/if_ath.c b/sys/dev/ath/if_ath.c index eaa0e6538fc..a9e76cae21c 100644 --- a/sys/dev/ath/if_ath.c +++ b/sys/dev/ath/if_ath.c @@ -2914,7 +2914,7 @@ ath_descdma_setup(struct ath_softc *sc, * in the descriptor. */ if (ATH_DESC_4KB_BOUND_CHECK(bf->bf_daddr, - dd->dd_descsize * ndesc)) { + dd->dd_descsize)) { /* Start at the next page */ ds += 0x1000 - (bf->bf_daddr & 0xFFF); bf->bf_desc = (struct ath_desc *) ds; @@ -2932,6 +2932,12 @@ ath_descdma_setup(struct ath_softc *sc, bf->bf_lastds = bf->bf_desc; /* Just an initial value */ TAILQ_INSERT_TAIL(head, bf, bf_list); } + + /* + * XXX TODO: ensure that ds doesn't overflow the descriptor + * allocation otherwise weird stuff will occur and crash your + * machine. + */ return 0; /* XXX this should likely just call ath_descdma_cleanup() */ fail3: