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From:   Zhouyang Jia <jiazhouyang09@gmail.com>
Cc:     Zhouyang Jia <jiazhouyang09@gmail.com>,
        Ian Abbott <abbotti@mev.co.uk>,
        H Hartley Sweeten <hsweeten@visionengravers.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Amitoj Kaur Chawla <amitoj1606@gmail.com>,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
Subject: [PATCH] staging: comedi: add error handling for vmap
Date:   Tue, 12 Jun 2018 11:25:35 +0800
Message-Id: <1528773937-38106-1-git-send-email-jiazhouyang09@gmail.com>
To:     unlisted-recipients:; (no To-header on input)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When vmap fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling vmap.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
 drivers/staging/comedi/comedi_buf.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
index f693c2c..5e48693 100644
--- a/drivers/staging/comedi/comedi_buf.c
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -132,9 +132,12 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
 	spin_unlock_irqrestore(&s->spin_lock, flags);
 
 	/* vmap the prealloc_buf if all the pages were allocated */
-	if (i == n_pages)
+	if (i == n_pages) {
 		async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
 					   COMEDI_PAGE_PROTECTION);
+		if (!async->prealloc_buf)
+			dev_err(dev->class_dev, "failed to vmap pages\n");
+	}
 
 	vfree(pages);
 }
-- 
2.7.4