linux-kernel - [PATCH 2/3] usb: early: xhci-dbc: Optimize early_xdbc

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Message-Id: <687bbcd940c59fbddd0e3a8b578fd3422962e50f.1675016180.git.christophe.jaillet@wanadoo.fr>
Date:   Sun, 29 Jan 2023 19:23:09 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     gregkh@...uxfoundation.org, peterz@...radead.org, pmladek@...e.com,
        john.ogness@...utronix.de, baolu.lu@...ux.intel.com,
        tglx@...utronix.de, mingo@...nel.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 2/3] usb: early: xhci-dbc: Optimize early_xdbc_write()

There is no point in zeroing 'buf'.
It would be cleared only once, and if the 'while' loop is executed several
times, all but the first run would have a 'dirty' buffer.
Moreover, the size of the chunk is computed in the loop and this size is
passed to xdbc_bulk_write().

So remove this useless memset().

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
Untested.
---
 drivers/usb/early/xhci-dbc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index f3e23be227d4..965a24e47c0f 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -881,7 +881,7 @@ static void early_xdbc_write(struct console *con, const char *str, u32 n)
 
 	if (!xdbc.xdbc_reg)
 		return;
-	memset(buf, 0, XDBC_MAX_PACKET);
+
 	while (n > 0) {
 		for (chunk = 0; chunk < XDBC_MAX_PACKET && n > 0; str++, chunk++, n--) {
 
-- 
2.34.1