net: ipa: prevent concurrent replenish

We have seen cases where an endpoint RX completion interrupt arrives
while replenishing for the endpoint is underway.  This causes another
instance of replenishing to begin as part of completing the receive
transaction.  If this occurs it can lead to transaction corruption.

Use a new flag to ensure only one replenish instance for an endpoint
executes at a time.

Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index cddddcedaf72bb3af8e4d916812f3fdda8588be2..68291a3efd040c1ef13a72864266f5c255f5cbaa 100644 (file)
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1088,15 +1088,27 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
                return;
        }
 
+       /* If already active, just update the backlog */
+       if (test_and_set_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags)) {
+               if (add_one)
+                       atomic_inc(&endpoint->replenish_backlog);
+               return;
+       }
+
        while (atomic_dec_not_zero(&endpoint->replenish_backlog))
                if (ipa_endpoint_replenish_one(endpoint))
                        goto try_again_later;
+
+       clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
+
        if (add_one)
                atomic_inc(&endpoint->replenish_backlog);
 
        return;
 
 try_again_later:
+       clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
+
        /* The last one didn't succeed, so fix the backlog */
        delta = add_one ? 2 : 1;
        backlog = atomic_add_return(delta, &endpoint->replenish_backlog);
@@ -1691,6 +1703,7 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
                 * backlog is the same as the maximum outstanding TREs.
                 */
                clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
+               clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
                atomic_set(&endpoint->replenish_saved,
                           gsi_channel_tre_max(gsi, endpoint->channel_id));
                atomic_set(&endpoint->replenish_backlog, 0);

diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h
index 07d5c20e5f00004771179489796b5a859eef4b96..0313cdc607de3f2b2f0b543cadb740848a9b1115 100644 (file)
--- a/drivers/net/ipa/ipa_endpoint.h
+++ b/drivers/net/ipa/ipa_endpoint.h
@@ -44,10 +44,12 @@ enum ipa_endpoint_name {
  * enum ipa_replenish_flag:    RX buffer replenish flags
  *
  * @IPA_REPLENISH_ENABLED:     Whether receive buffer replenishing is enabled
+ * @IPA_REPLENISH_ACTIVE:      Whether replenishing is underway
  * @IPA_REPLENISH_COUNT:       Number of defined replenish flags
  */
 enum ipa_replenish_flag {
        IPA_REPLENISH_ENABLED,
+       IPA_REPLENISH_ACTIVE,
        IPA_REPLENISH_COUNT,    /* Number of flags (must be last) */
 };