From 6c0e3b5ce94947b311348c367db9e11dcb2ccc93 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 12 Jan 2022 07:30:10 -0600 Subject: [PATCH 1/3] net: ipa: fix atomic update in ipa_endpoint_replenish() In ipa_endpoint_replenish(), if an error occurs when attempting to replenish a receive buffer, we just quit and try again later. In that case we increment the backlog count to reflect that the attempt was unsuccessful. Then, if the add_one flag was true we increment the backlog again. This second increment is not included in the backlog local variable though, and its value determines whether delayed work should be scheduled. This is a bug. Fix this by determining whether 1 or 2 should be added to the backlog before adding it in a atomic_add_return() call. Reviewed-by: Matthias Kaehlcke Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints") Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ipa/ipa_endpoint.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index 49d9a077d037..8b055885cf3c 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -1080,6 +1080,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one) { struct gsi *gsi; u32 backlog; + int delta; if (!endpoint->replenish_enabled) { if (add_one) @@ -1097,10 +1098,8 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one) try_again_later: /* The last one didn't succeed, so fix the backlog */ - backlog = atomic_inc_return(&endpoint->replenish_backlog); - - if (add_one) - atomic_inc(&endpoint->replenish_backlog); + delta = add_one ? 2 : 1; + backlog = atomic_add_return(delta, &endpoint->replenish_backlog); /* Whenever a receive buffer transaction completes we'll try to * replenish again. It's unlikely, but if we fail to supply even From c1aaa01dbf4cef95af3e04a5a43986c290e06ea3 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 12 Jan 2022 07:30:11 -0600 Subject: [PATCH 2/3] net: ipa: use a bitmap for endpoint replenish_enabled Define a new replenish_flags bitmap to contain Boolean flags associated with an endpoint's replenishing state. Replace the replenish_enabled field with a flag in that bitmap. This is to prepare for the next patch, which adds another flag. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ipa/ipa_endpoint.c | 8 ++++---- drivers/net/ipa/ipa_endpoint.h | 15 +++++++++++++-- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index 8b055885cf3c..cddddcedaf72 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -1082,7 +1082,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one) u32 backlog; int delta; - if (!endpoint->replenish_enabled) { + if (!test_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags)) { if (add_one) atomic_inc(&endpoint->replenish_saved); return; @@ -1119,7 +1119,7 @@ static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint) u32 max_backlog; u32 saved; - endpoint->replenish_enabled = true; + set_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags); while ((saved = atomic_xchg(&endpoint->replenish_saved, 0))) atomic_add(saved, &endpoint->replenish_backlog); @@ -1133,7 +1133,7 @@ static void ipa_endpoint_replenish_disable(struct ipa_endpoint *endpoint) { u32 backlog; - endpoint->replenish_enabled = false; + clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags); while ((backlog = atomic_xchg(&endpoint->replenish_backlog, 0))) atomic_add(backlog, &endpoint->replenish_saved); } @@ -1690,7 +1690,7 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint) /* RX transactions require a single TRE, so the maximum * backlog is the same as the maximum outstanding TREs. */ - endpoint->replenish_enabled = false; + clear_bit(IPA_REPLENISH_ENABLED, 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 0a859d10312d..07d5c20e5f00 100644 --- a/drivers/net/ipa/ipa_endpoint.h +++ b/drivers/net/ipa/ipa_endpoint.h @@ -40,6 +40,17 @@ enum ipa_endpoint_name { #define IPA_ENDPOINT_MAX 32 /* Max supported by driver */ +/** + * enum ipa_replenish_flag: RX buffer replenish flags + * + * @IPA_REPLENISH_ENABLED: Whether receive buffer replenishing is enabled + * @IPA_REPLENISH_COUNT: Number of defined replenish flags + */ +enum ipa_replenish_flag { + IPA_REPLENISH_ENABLED, + IPA_REPLENISH_COUNT, /* Number of flags (must be last) */ +}; + /** * struct ipa_endpoint - IPA endpoint information * @ipa: IPA pointer @@ -51,7 +62,7 @@ enum ipa_endpoint_name { * @trans_tre_max: Maximum number of TRE descriptors per transaction * @evt_ring_id: GSI event ring used by the endpoint * @netdev: Network device pointer, if endpoint uses one - * @replenish_enabled: Whether receive buffer replenishing is enabled + * @replenish_flags: Replenishing state flags * @replenish_ready: Number of replenish transactions without doorbell * @replenish_saved: Replenish requests held while disabled * @replenish_backlog: Number of buffers needed to fill hardware queue @@ -72,7 +83,7 @@ struct ipa_endpoint { struct net_device *netdev; /* Receive buffer replenishing for RX endpoints */ - bool replenish_enabled; + DECLARE_BITMAP(replenish_flags, IPA_REPLENISH_COUNT); u32 replenish_ready; atomic_t replenish_saved; atomic_t replenish_backlog; From 998c0bd2b3715244da7639cc4e6a2062cb79c3f4 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 12 Jan 2022 07:30:12 -0600 Subject: [PATCH 3/3] 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 Signed-off-by: David S. Miller --- drivers/net/ipa/ipa_endpoint.c | 13 +++++++++++++ drivers/net/ipa/ipa_endpoint.h | 2 ++ 2 files changed, 15 insertions(+) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index cddddcedaf72..68291a3efd04 100644 --- 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 07d5c20e5f00..0313cdc607de 100644 --- 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) */ };