ice: port fix for chk_linearlize

This is a port of commit 248de22e638f ("i40e/i40evf: Account for frags
split over multiple descriptors in check linearize")

As part of testing workloads (read/write) using larger IO size (128K)
tx_timeout is observed and whenever it happens, it was due to
tx_linearize.

Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 53c67ee..77de886 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -2292,10 +2292,30 @@ static bool __ice_chk_linearize(struct sk_buff *skb)
        /* Walk through fragments adding latest fragment, testing it, and
         * then removing stale fragments from the sum.
         */
-       stale = &skb_shinfo(skb)->frags[0];
-       for (;;) {
+       for (stale = &skb_shinfo(skb)->frags[0];; stale++) {
+               int stale_size = skb_frag_size(stale);
+
                sum += skb_frag_size(frag++);
 
+               /* The stale fragment may present us with a smaller
+                * descriptor than the actual fragment size. To account
+                * for that we need to remove all the data on the front and
+                * figure out what the remainder would be in the last
+                * descriptor associated with the fragment.
+                */
+               if (stale_size > ICE_MAX_DATA_PER_TXD) {
+                       int align_pad = -(skb_frag_off(stale)) &
+                                       (ICE_MAX_READ_REQ_SIZE - 1);
+
+                       sum -= align_pad;
+                       stale_size -= align_pad;
+
+                       do {
+                               sum -= ICE_MAX_DATA_PER_TXD_ALIGNED;
+                               stale_size -= ICE_MAX_DATA_PER_TXD_ALIGNED;
+                       } while (stale_size > ICE_MAX_DATA_PER_TXD);
+               }
+
                /* if sum is negative we failed to make sufficient progress */
                if (sum < 0)
                        return true;
@@ -2303,7 +2323,7 @@ static bool __ice_chk_linearize(struct sk_buff *skb)
                if (!nr_frags--)
                        break;
 
-               sum -= skb_frag_size(stale++);
+               sum -= stale_size;
        }
 
        return false;