diff mbox series

[net-next] net: ipa: compute proper aggregation limit

Message ID 20220421185333.1371632-1-elder@linaro.org (mailing list archive)
State Accepted
Commit c5794097b269f15961ed78f7f27b50e51766dec9
Delegated to: Netdev Maintainers
Headers show
Series [net-next] net: ipa: compute proper aggregation limit | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 1 maintainers not CCed: pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Alex Elder April 21, 2022, 6:53 p.m. UTC
The aggregation byte limit for an endpoint is currently computed
based on the endpoint's receive buffer size.

However, some bytes at the front of each receive buffer are reserved
on the assumption that--as with SKBs--it might be useful to insert
data (such as headers) before what lands in the buffer.

The aggregation byte limit currently doesn't take into account that
reserved space, and as a result, aggregation could require space
past that which is available in the buffer.

Fix this by reducing the size used to compute the aggregation byte
limit by the NET_SKB_PAD offset reserved for each receive buffer.

Signed-off-by: Alex Elder <elder@linaro.org>
---
Note:  This is a bug, but it won't apply cleanly to older kernels,
       so I will be posting back-ports separately.

 drivers/net/ipa/ipa_endpoint.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org April 25, 2022, 10:30 a.m. UTC | #1
Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Thu, 21 Apr 2022 13:53:33 -0500 you wrote:
> The aggregation byte limit for an endpoint is currently computed
> based on the endpoint's receive buffer size.
> 
> However, some bytes at the front of each receive buffer are reserved
> on the assumption that--as with SKBs--it might be useful to insert
> data (such as headers) before what lands in the buffer.
> 
> [...]

Here is the summary with links:
  - [net-next] net: ipa: compute proper aggregation limit
    https://git.kernel.org/netdev/net-next/c/c5794097b269

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 888e94278a84f..e133eb2bebcfb 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -130,9 +130,10 @@  static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
 		 */
 		if (data->endpoint.config.aggregation) {
 			limit += SZ_1K * aggr_byte_limit_max(ipa->version);
-			if (buffer_size > limit) {
+			if (buffer_size - NET_SKB_PAD > limit) {
 				dev_err(dev, "RX buffer size too large for aggregated RX endpoint %u (%u > %u)\n",
-					data->endpoint_id, buffer_size, limit);
+					data->endpoint_id,
+					buffer_size - NET_SKB_PAD, limit);
 
 				return false;
 			}
@@ -739,6 +740,7 @@  static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
 	if (endpoint->data->aggregation) {
 		if (!endpoint->toward_ipa) {
 			const struct ipa_endpoint_rx_data *rx_data;
+			u32 buffer_size;
 			bool close_eof;
 			u32 limit;
 
@@ -746,7 +748,8 @@  static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
 			val |= u32_encode_bits(IPA_ENABLE_AGGR, AGGR_EN_FMASK);
 			val |= u32_encode_bits(IPA_GENERIC, AGGR_TYPE_FMASK);
 
-			limit = ipa_aggr_size_kb(rx_data->buffer_size);
+			buffer_size = rx_data->buffer_size;
+			limit = ipa_aggr_size_kb(buffer_size - NET_SKB_PAD);
 			val |= aggr_byte_limit_encoded(version, limit);
 
 			limit = IPA_AGGR_TIME_LIMIT;