tcp: Remove redundant checks when setting eff_sacks

Remove redundant checks when setting eff_sacks and make the number of SACKs a
compile time constant. Now that the options code knows how many SACK blocks can
fit in the header, we don't need to have the SACK code guessing at it.

Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 07e79bdb9cdf..2e2557388e36 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -224,6 +224,12 @@ struct tcp_options_received {
         u16     mss_clamp;      /* Maximal mss, negotiated at connection setup */
 };
 
+/* This is the max number of SACKS that we'll generate and process. It's safe
+ * to increse this, although since:
+ *   size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
+ * only four options will fit in a standard TCP header */
+#define TCP_NUM_SACKS 4
+
 struct tcp_request_sock {
         struct inet_request_sock        req;
 #ifdef CONFIG_TCP_MD5SIG