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>

diff --git a/drivers/net/myri10ge/myri10ge.c b/drivers/net/myri10ge/myri10ge.c
index c216e6a5d2353ff4c2643e3b054c99910c6b5c2a..1e7fa2facbe12ee712c02fb56c0242c54463f1ec 100644 (file)
--- 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 */