linux-kernel - [PATCH] pgo: Clean up prf

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Message-Id: <20210607230241.3797373-1-keescook@chromium.org>
Date:   Mon,  7 Jun 2021 16:02:41 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     Kees Cook <keescook@...omium.org>,
        Jarmo Tiitto <jarmo.tiitto@...il.com>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Bill Wendling <wcw@...gle.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux@...glegroups.com
Subject: [PATCH] pgo: Clean up prf_open() error paths

Change coding style for prf_open() error handling paths. Additionally
fix up comments to be complete sentences with punctuation.

Signed-off-by: Kees Cook <keescook@...omium.org>
---
This is on top of Jarmo's recent fixes.
---
 kernel/pgo/fs.c | 49 ++++++++++++++++++++-----------------------------
 1 file changed, 20 insertions(+), 29 deletions(-)

diff --git a/kernel/pgo/fs.c b/kernel/pgo/fs.c
index 0ce0dc9caf7a..3c5aa7c2a4ce 100644
--- a/kernel/pgo/fs.c
+++ b/kernel/pgo/fs.c
@@ -234,17 +234,14 @@ static unsigned long prf_buffer_size(void)
  */
 static int prf_serialize(struct prf_private_data *p, size_t buf_size)
 {
-	int err = 0;
 	void *buffer;
 
 	/* get buffer size, again. */
 	p->size = prf_buffer_size();
 
 	/* check for unlikely overflow. */
-	if (p->size > buf_size) {
-		err = -EAGAIN;
-		goto out;
-	}
+	if (p->size > buf_size)
+		return -EAGAIN;
 
 	buffer = p->buffer;
 
@@ -256,8 +253,7 @@ static int prf_serialize(struct prf_private_data *p, size_t buf_size)
 
 	prf_serialize_values(&buffer);
 
-out:
-	return err;
+	return 0;
 }
 
 /* open() implementation for PGO. Creates a copy of the profiling data set. */
@@ -266,52 +262,47 @@ static int prf_open(struct inode *inode, struct file *file)
 	struct prf_private_data *data;
 	unsigned long flags;
 	size_t buf_size;
-	int err = 0;
+	int err = -EINVAL;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data) {
-		err = -ENOMEM;
-		goto out_free;
-	}
+	if (!data)
+		return -ENOMEM;
 
-	/* get initial buffer size */
+	/* Get initial buffer size. */
 	flags = prf_lock();
 	data->size = prf_buffer_size();
 	prf_unlock(flags);
 
 	do {
-		if (data->buffer)
-			vfree(data->buffer);
+		vfree(data->buffer);
 
-		/* allocate, round up to page size. */
+		/* Allocate, round up to page size. */
 		buf_size = PAGE_ALIGN(data->size);
 		data->buffer = vzalloc(buf_size);
 
 		if (!data->buffer) {
 			err = -ENOMEM;
-			goto out_free;
+			break;
 		}
 
 		/*
-		 * try serialize and get actual
-		 * data length in data->size
+		 * Try serialize and get actual
+		 * data length in data->size.
 		 */
 		flags = prf_lock();
 		err = prf_serialize(data, buf_size);
 		prf_unlock(flags);
-		/* in unlikely case, try again. */
+		/* In unlikely case, try again. */
 	} while (err == -EAGAIN);
 
-	if (err)
-		goto out_free;
-
-	file->private_data = data;
-	return 0;
+	if (err < 0) {
+		if (data)
+			vfree(data->buffer);
+		kfree(data);
+	} else {
+		file->private_data = data;
+	}
 
-out_free:
-	if (data)
-		vfree(data->buffer);
-	kfree(data);
 	return err;
 }
 
-- 
2.25.1