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From: Xianting Tian <xianting.tian@linux.alibaba.com>
To: gregkh@linuxfoundation.org, jirislaby@kernel.org,
	amit@kernel.org, arnd@arndb.de, osandov@fb.com
Cc: shile.zhang@linux.alibaba.com, linuxppc-dev@lists.ozlabs.org,
	virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org,
	Xianting Tian <xianting.tian@linux.alibaba.com>
Subject: [PATCH v8 3/3] virtio-console: remove unnecessary kmemdup()
Date: Wed, 18 Aug 2021 16:21:22 +0800	[thread overview]
Message-ID: <20210818082122.166881-4-xianting.tian@linux.alibaba.com> (raw)
In-Reply-To: <20210818082122.166881-1-xianting.tian@linux.alibaba.com>

This revert commit c4baad5029 ("virtio-console: avoid DMA from stack")

hvc framework will never pass stack memory to the put_chars() function,
So the calling of kmemdup() is unnecessary, we can remove it.

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Reviewed-by: Shile Zhang <shile.zhang@linux.alibaba.com>
---
 drivers/char/virtio_console.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 7eaf303a7..4ed3ffb1d 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1117,8 +1117,6 @@ static int put_chars(u32 vtermno, const char *buf, int count)
 {
 	struct port *port;
 	struct scatterlist sg[1];
-	void *data;
-	int ret;
 
 	if (unlikely(early_put_chars))
 		return early_put_chars(vtermno, buf, count);
@@ -1127,14 +1125,8 @@ static int put_chars(u32 vtermno, const char *buf, int count)
 	if (!port)
 		return -EPIPE;
 
-	data = kmemdup(buf, count, GFP_ATOMIC);
-	if (!data)
-		return -ENOMEM;
-
-	sg_init_one(sg, data, count);
-	ret = __send_to_port(port, sg, 1, count, data, false);
-	kfree(data);
-	return ret;
+	sg_init_one(sg, buf, count);
+	return __send_to_port(port, sg, 1, count, (void *)buf, false);
 }
 
 /*
-- 
2.17.1


      parent reply	other threads:[~2021-08-18  8:22 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18  8:21 [PATCH v8 0/3] make hvc pass dma capable memory to its backend Xianting Tian
2021-08-18  8:21 ` [PATCH v8 1/3] tty: hvc: use correct dma alignment size Xianting Tian
2021-08-18  8:21 ` [PATCH v8 2/3] tty: hvc: pass DMA capable memory to put_chars() Xianting Tian
2021-08-18 11:03   ` kernel test robot
2021-08-18 17:41   ` kernel test robot
2021-08-20  6:49   ` Daniel Axtens
2021-08-20  8:43     ` Xianting TIan
2021-09-18 12:32       ` Xianting Tian
2021-09-18 12:40         ` Greg KH
2021-09-18 12:47           ` Xianting Tian
2021-08-20 12:34     ` Michael Ellerman
2021-08-18  8:21 ` Xianting Tian [this message]

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