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From: Alex Elder <elder@linaro.org>
To: davem@davemloft.net, kuba@kernel.org
Cc: elder@kernel.org, evgreen@chromium.org,
	bjorn.andersson@linaro.org, cpratapa@codeaurora.org,
	subashab@codeaurora.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH net-next 1/5] net: ipa: count actual work done in gsi_channel_poll()
Date: Wed, 20 Jan 2021 16:03:57 -0600	[thread overview]
Message-ID: <20210120220401.10713-2-elder@linaro.org> (raw)
In-Reply-To: <20210120220401.10713-1-elder@linaro.org>

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@linaro.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


  reply	other threads:[~2021-01-20 22:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20 22:03 [PATCH net-next 0/5] net: ipa: NAPI poll updates Alex Elder
2021-01-20 22:03 ` Alex Elder [this message]
2021-01-20 22:03 ` [PATCH net-next 2/5] net: ipa: heed napi_complete() return value Alex Elder
2021-01-20 22:03 ` [PATCH net-next 3/5] net: ipa: have gsi_channel_update() return a value Alex Elder
2021-01-21  5:35   ` Jakub Kicinski
2021-01-21 11:34     ` Alex Elder
2021-01-20 22:04 ` [PATCH net-next 4/5] net: ipa: repurpose gsi_irq_ieob_disable() Alex Elder
2021-01-20 22:04 ` [PATCH net-next 5/5] net: ipa: disable IEOB interrupts before clearing Alex Elder

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