netdev - [PATCH net-next v2 3/6] net: ipa: drop packet if status has valid tag

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Message-Id: <20210126185703.29087-4-elder@linaro.org>
Date:   Tue, 26 Jan 2021 12:57:00 -0600
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     elder@...nel.org, evgreen@...omium.org, bjorn.andersson@...aro.org,
        cpratapa@...eaurora.org, subashab@...eaurora.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next v2 3/6] net: ipa: drop packet if status has valid tag

Introduce ipa_endpoint_status_tag(), which returns true if received
status indicates its tag field is valid.  The endpoint parameter is
not yet used.

Call this from ipa_status_drop_packet(), and drop the packet if the
status indicates the tag was valid.  Pass the endpoint pointer to
ipa_status_drop_packet(), and rename it ipa_endpoint_status_drop().
The endpoint will be used in the next patch.

Signed-off-by: Alex Elder <elder@...aro.org>
---
v2: Use le16_get_bits() to access the status mask tag field properly.

 drivers/net/ipa/ipa_endpoint.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index c5524215054c8..68970a3baa47a 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -69,8 +69,11 @@ struct ipa_status {
 };
 
 /* Field masks for struct ipa_status structure fields */
+#define IPA_STATUS_MASK_TAG_VALID_FMASK		GENMASK(4, 4)
+#define IPA_STATUS_SRC_IDX_FMASK		GENMASK(4, 0)
 #define IPA_STATUS_DST_IDX_FMASK		GENMASK(4, 0)
 #define IPA_STATUS_FLAGS1_RT_RULE_ID_FMASK	GENMASK(31, 22)
+#define IPA_STATUS_FLAGS2_TAG_FMASK		GENMASK_ULL(63, 16)
 
 #ifdef IPA_VALIDATE
 
@@ -1172,11 +1175,22 @@ static bool ipa_endpoint_status_skip(struct ipa_endpoint *endpoint,
 	return false;	/* Don't skip this packet, process it */
 }
 
+static bool ipa_endpoint_status_tag(struct ipa_endpoint *endpoint,
+				    const struct ipa_status *status)
+{
+	return !!le16_get_bits(status->mask, IPA_STATUS_MASK_TAG_VALID_FMASK);
+}
+
 /* Return whether the status indicates the packet should be dropped */
-static bool ipa_status_drop_packet(const struct ipa_status *status)
+static bool ipa_endpoint_status_drop(struct ipa_endpoint *endpoint,
+				     const struct ipa_status *status)
 {
 	u32 val;
 
+	/* If the status indicates a tagged transfer, we'll drop the packet */
+	if (ipa_endpoint_status_tag(endpoint, status))
+		return true;
+
 	/* Deaggregation exceptions we drop; all other types we consume */
 	if (status->exception)
 		return status->exception == IPA_STATUS_EXCEPTION_DEAGGR;
@@ -1225,7 +1239,7 @@ static void ipa_endpoint_status_parse(struct ipa_endpoint *endpoint,
 		if (endpoint->data->checksum)
 			len += sizeof(struct rmnet_map_dl_csum_trailer);
 
-		if (!ipa_status_drop_packet(status)) {
+		if (!ipa_endpoint_status_drop(endpoint, status)) {
 			void *data2;
 			u32 extra;
 			u32 len2;
-- 
2.20.1