linux-kernel - [PATCH net-next 1/5] net: ipa: count actual work done in gsi_channel

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Message-Id: <20210120220401.10713-2-elder@linaro.org>
Date:   Wed, 20 Jan 2021 16:03:57 -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 1/5] net: ipa: count actual work done in gsi_channel_poll()

There is an off-by-one problem in gsi_channel_poll().  The count of
transactions completed is incremented each time through the loop
*before* determining whether there is any more work to do.  As a
result, if we exit the loop early the counter its value is one more
than the number of transactions actually processed.

Instead, increment the count after processing, to ensure it reflects
the number of processed transactions.  The result is more naturally
described as a for loop rather than a while loop, so change that.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/gsi.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 5b29f7d9d6ac1..56a5eb61b20c4 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -1543,13 +1543,12 @@ static struct gsi_trans *gsi_channel_poll_one(struct gsi_channel *channel)
 static int gsi_channel_poll(struct napi_struct *napi, int budget)
 {
 	struct gsi_channel *channel;
-	int count = 0;
+	int count;
 
 	channel = container_of(napi, struct gsi_channel, napi);
-	while (count < budget) {
+	for (count = 0; count < budget; count++) {
 		struct gsi_trans *trans;
 
-		count++;
 		trans = gsi_channel_poll_one(channel);
 		if (!trans)
 			break;
-- 
2.20.1