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net: ipa: prevent concurrent replenish

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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>
This commit is contained in:
Alex Elder 2022-01-12 07:30:12 -06:00 committed by David S. Miller
parent c1aaa01dbf
commit 998c0bd2b3
2 changed files with 15 additions and 0 deletions
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13
drivers/net/ipa/ipa_endpoint.c
View File

@ -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);

2
drivers/net/ipa/ipa_endpoint.h
View File

@ -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) */
};