linux-kernel - [PATCH] usb: fixing some clang warnings inside usb host drivers

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Message-Id: <20211218042420.28466-1-jcfaracco@gmail.com>
Date:   Sat, 18 Dec 2021 01:24:20 -0300
From:   Julio Faracco <jcfaracco@...il.com>
To:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     stern@...land.harvard.edu, gregkh@...uxfoundation.org,
        axboe@...nel.dk, tglx@...utronix.de, damien.lemoal@....com,
        dkadashev@...il.com, paul.gortmaker@...driver.com,
        zhouyanjie@...yeetech.com, niklas.cassel@....com,
        penguin-kernel@...ove.sakura.ne.jp, macro@...am.me.uk,
        caihuoqing@...du.com, jcfaracco@...il.com
Subject: [PATCH] usb: fixing some clang warnings inside usb host drivers

Clang is reporting some issues related variable values not used and
other issues inside some USB host drivers. This commit removes some
trashes and adds some strategies to mitigate those warnings.

The most important is the maxpacket not checking for zeros inside both
functions qtd_fill(). Even if this variable is always higher than zero,
it should be checked to avoid this kind of verbosity.

Signed-off-by: Julio Faracco <jcfaracco@...il.com>
---
 drivers/usb/host/ehci-dbg.c     | 1 -
 drivers/usb/host/ehci-q.c       | 2 +-
 drivers/usb/host/ohci-dbg.c     | 1 -
 drivers/usb/host/oxu210hp-hcd.c | 2 +-
 4 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/ehci-dbg.c b/drivers/usb/host/ehci-dbg.c
index 0b7f1edd9eec..70b4ff65295a 100644
--- a/drivers/usb/host/ehci-dbg.c
+++ b/drivers/usb/host/ehci-dbg.c
@@ -903,7 +903,6 @@ static ssize_t fill_registers_buffer(struct debug_buffer *buf)
 	temp = scnprintf(next, size, "complete %ld unlink %ld\n",
 		ehci->stats.complete, ehci->stats.unlink);
 	size -= temp;
-	next += temp;
 #endif
 
 done:
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 2cbf4f85bff3..98cb44414e78 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -64,7 +64,7 @@ qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
 		}
 
 		/* short packets may only terminate transfers */
-		if (count != len)
+		if (count != len && maxpacket > 0)
 			count -= (count % maxpacket);
 	}
 	qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
diff --git a/drivers/usb/host/ohci-dbg.c b/drivers/usb/host/ohci-dbg.c
index 4f267dc93882..6fc9c46ffe3c 100644
--- a/drivers/usb/host/ohci-dbg.c
+++ b/drivers/usb/host/ohci-dbg.c
@@ -561,7 +561,6 @@ static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
 
 			} else {
 				/* we've seen it and what's after */
-				temp = 0;
 				ed = NULL;
 			}
 
diff --git a/drivers/usb/host/oxu210hp-hcd.c b/drivers/usb/host/oxu210hp-hcd.c
index e82ff2a49672..8a20d9d3c377 100644
--- a/drivers/usb/host/oxu210hp-hcd.c
+++ b/drivers/usb/host/oxu210hp-hcd.c
@@ -1232,7 +1232,7 @@ static int qtd_fill(struct ehci_qtd *qtd, dma_addr_t buf, size_t len,
 		}
 
 		/* short packets may only terminate transfers */
-		if (count != len)
+		if (count != len && maxpacket > 0)
 			count -= (count % maxpacket);
 	}
 	qtd->hw_token = cpu_to_le32((count << 16) | token);
-- 
2.31.1