myri10ge: fix management of the firmware 4KB boundary crossing restriction

Simpler way of dealing with the firmware 4KB boundary crossing
restriction for rx buffers.  This fixes a variety of memory
corruption issues when using an "uncommon" MTU with a 16KB
page size.

Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 8 insertions, 11 deletions

diff --git a/drivers/net/myri10ge/myri10ge.c b/drivers/net/myri10ge/myri10ge.c
index c216e6a5d235..1e7fa2facbe1 100644
--- a/drivers/net/myri10ge/myri10ge.c
+++ b/drivers/net/myri10ge/myri10ge.c
@@ -900,19 +900,9 @@ myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
         /* try to refill entire ring */
         while (rx->fill_cnt != (rx->cnt + rx->mask + 1)) {
                 idx = rx->fill_cnt & rx->mask;
-
-                if ((bytes < MYRI10GE_ALLOC_SIZE / 2) &&
-                    (rx->page_offset + bytes <= MYRI10GE_ALLOC_SIZE)) {
+                if (rx->page_offset + bytes <= MYRI10GE_ALLOC_SIZE) {
                         /* we can use part of previous page */
                         get_page(rx->page);
-#if MYRI10GE_ALLOC_SIZE > 4096
-                        /* Firmware cannot cross 4K boundary.. */
-                        if ((rx->page_offset >> 12) !=
-                            ((rx->page_offset + bytes - 1) >> 12)) {
-                                rx->page_offset =
-                                    (rx->page_offset + bytes) & ~4095;
-                        }
-#endif
                 } else {
                         /* we need a new page */
                         page =
@@ -941,6 +931,13 @@ myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
 
                 /* start next packet on a cacheline boundary */
                 rx->page_offset += SKB_DATA_ALIGN(bytes);
+
+#if MYRI10GE_ALLOC_SIZE > 4096
+                /* don't cross a 4KB boundary */
+                if ((rx->page_offset >> 12) !=
+                    ((rx->page_offset + bytes - 1) >> 12))
+                        rx->page_offset = (rx->page_offset + 4096) & ~4095;
+#endif
                 rx->fill_cnt++;
 
                 /* copy 8 descriptors to the firmware at a time */