[PATCH 0/4] Rearrange functions to remove forward declarations

[PATCH 0/4] Rearrange functions to remove forward declarations

[PrasannaKumar Muralidharan]

This patch series rearranges functions such that forward declarations
becomes unnecessary. Remove those forward declaration.

This patch series is boot tested without user space in qemu with
CONFIG_HW_RANDOM=y.

PrasannaKumar Muralidharan (4):
  hw_random: core: Remove forward declaration by rearranging code
  hw_random: core: Rearranging rng_get_data to remove forward
    declaration
  hw_random: core: Rearranging start_khwrngd to remove forward
    declaration
  hw_random: core: Remove forward declaration of hwrng_init

 drivers/char/hw_random/core.c | 151 ++++++++++++++++++++----------------------
 1 file changed, 72 insertions(+), 79 deletions(-)

-- 
2.10.0

[PATCH 1/4] hw_random: core: Remove forward declaration by rearranging code

[PrasannaKumar Muralidharan]

Rearrange drop_current_rng such that its forward declaration is not
required.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
---
 drivers/char/hw_random/core.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 9701ac7..8e1f43c 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -49,7 +49,6 @@ module_param(default_quality, ushort, 0644);
 MODULE_PARM_DESC(default_quality,
 		 "default entropy content of hwrng per mill");
 
-static void drop_current_rng(void);
 static int hwrng_init(struct hwrng *rng);
 static void start_khwrngd(void);
 
@@ -83,6 +82,17 @@ static inline void cleanup_rng(struct kref *kref)
 	complete(&rng->cleanup_done);
 }
 
+static void drop_current_rng(void)
+{
+	BUG_ON(!mutex_is_locked(&rng_mutex));
+	if (!current_rng)
+		return;
+
+	/* decrease last reference for triggering the cleanup */
+	kref_put(&current_rng->ref, cleanup_rng);
+	current_rng = NULL;
+}
+
 static int set_current_rng(struct hwrng *rng)
 {
 	int err;
@@ -99,17 +109,6 @@ static int set_current_rng(struct hwrng *rng)
 	return 0;
 }
 
-static void drop_current_rng(void)
-{
-	BUG_ON(!mutex_is_locked(&rng_mutex));
-	if (!current_rng)
-		return;
-
-	/* decrease last reference for triggering the cleanup */
-	kref_put(&current_rng->ref, cleanup_rng);
-	current_rng = NULL;
-}
-
 /* Returns ERR_PTR(), NULL or refcounted hwrng */
 static struct hwrng *get_current_rng(void)
 {
-- 
2.10.0

[PATCH 2/4] hw_random: core: Rearranging rng_get_data to remove forward declaration

[PrasannaKumar Muralidharan]

Rearrange rng_get_data such that its forward declaration is not
required.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
---
 drivers/char/hw_random/core.c | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 8e1f43c..7e2b1a7 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -52,14 +52,30 @@ MODULE_PARM_DESC(default_quality,
 static int hwrng_init(struct hwrng *rng);
 static void start_khwrngd(void);
 
-static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
-			       int wait);
-
 static size_t rng_buffer_size(void)
 {
 	return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
 }
 
+static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
+			int wait) {
+	int present;
+
+	BUG_ON(!mutex_is_locked(&reading_mutex));
+	if (rng->read)
+		return rng->read(rng, (void *)buffer, size, wait);
+
+	if (rng->data_present)
+		present = rng->data_present(rng, wait);
+	else
+		present = 1;
+
+	if (present)
+		return rng->data_read(rng, (u32 *)buffer);
+
+	return 0;
+}
+
 static void add_early_randomness(struct hwrng *rng)
 {
 	int bytes_read;
@@ -178,25 +194,6 @@ static int rng_dev_open(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
-			int wait) {
-	int present;
-
-	BUG_ON(!mutex_is_locked(&reading_mutex));
-	if (rng->read)
-		return rng->read(rng, (void *)buffer, size, wait);
-
-	if (rng->data_present)
-		present = rng->data_present(rng, wait);
-	else
-		present = 1;
-
-	if (present)
-		return rng->data_read(rng, (u32 *)buffer);
-
-	return 0;
-}
-
 static ssize_t rng_dev_read(struct file *filp, char __user *buf,
 			    size_t size, loff_t *offp)
 {
-- 
2.10.0

[PATCH 3/4] hw_random: core: Rearranging start_khwrngd to remove forward declaration

[PrasannaKumar Muralidharan]

Rearrange start_khwrngd such that its forward declaration is not
required.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
---
 drivers/char/hw_random/core.c | 75 +++++++++++++++++++++----------------------
 1 file changed, 37 insertions(+), 38 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 7e2b1a7..534c2ae 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -50,7 +50,6 @@ MODULE_PARM_DESC(default_quality,
 		 "default entropy content of hwrng per mill");
 
 static int hwrng_init(struct hwrng *rng);
-static void start_khwrngd(void);
 
 static size_t rng_buffer_size(void)
 {
@@ -153,6 +152,43 @@ static void put_rng(struct hwrng *rng)
 	mutex_unlock(&rng_mutex);
 }
 
+static int hwrng_fillfn(void *unused)
+{
+	long rc;
+
+	while (!kthread_should_stop()) {
+		struct hwrng *rng;
+
+		rng = get_current_rng();
+		if (IS_ERR(rng) || !rng)
+			break;
+		mutex_lock(&reading_mutex);
+		rc = rng_get_data(rng, rng_fillbuf,
+				  rng_buffer_size(), 1);
+		mutex_unlock(&reading_mutex);
+		put_rng(rng);
+		if (rc <= 0) {
+			pr_warn("hwrng: no data available\n");
+			msleep_interruptible(10000);
+			continue;
+		}
+		/* Outside lock, sure, but y'know: randomness. */
+		add_hwgenerator_randomness((void *)rng_fillbuf, rc,
+					   rc * current_quality * 8 >> 10);
+	}
+	hwrng_fill = NULL;
+	return 0;
+}
+
+static void start_khwrngd(void)
+{
+	hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
+	if (IS_ERR(hwrng_fill)) {
+		pr_err("hwrng_fill thread creation failed");
+		hwrng_fill = NULL;
+	}
+}
+
 static int hwrng_init(struct hwrng *rng)
 {
 	if (kref_get_unless_zero(&rng->ref))
@@ -387,43 +423,6 @@ static int __init register_miscdev(void)
 	return misc_register(&rng_miscdev);
 }
 
-static int hwrng_fillfn(void *unused)
-{
-	long rc;
-
-	while (!kthread_should_stop()) {
-		struct hwrng *rng;
-
-		rng = get_current_rng();
-		if (IS_ERR(rng) || !rng)
-			break;
-		mutex_lock(&reading_mutex);
-		rc = rng_get_data(rng, rng_fillbuf,
-				  rng_buffer_size(), 1);
-		mutex_unlock(&reading_mutex);
-		put_rng(rng);
-		if (rc <= 0) {
-			pr_warn("hwrng: no data available\n");
-			msleep_interruptible(10000);
-			continue;
-		}
-		/* Outside lock, sure, but y'know: randomness. */
-		add_hwgenerator_randomness((void *)rng_fillbuf, rc,
-					   rc * current_quality * 8 >> 10);
-	}
-	hwrng_fill = NULL;
-	return 0;
-}
-
-static void start_khwrngd(void)
-{
-	hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
-	if (IS_ERR(hwrng_fill)) {
-		pr_err("hwrng_fill thread creation failed");
-		hwrng_fill = NULL;
-	}
-}
-
 int hwrng_register(struct hwrng *rng)
 {
 	int err = -EINVAL;
-- 
2.10.0

[PATCH 4/4] hw_random: core: Remove forward declaration of hwrng_init

[PrasannaKumar Muralidharan]

Rearrange set_current_rng such that hwrng_init's forward declaration can
be removed.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
---
 drivers/char/hw_random/core.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 534c2ae..328d065 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -49,8 +49,6 @@ module_param(default_quality, ushort, 0644);
 MODULE_PARM_DESC(default_quality,
 		 "default entropy content of hwrng per mill");
 
-static int hwrng_init(struct hwrng *rng);
-
 static size_t rng_buffer_size(void)
 {
 	return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
@@ -108,22 +106,6 @@ static void drop_current_rng(void)
 	current_rng = NULL;
 }
 
-static int set_current_rng(struct hwrng *rng)
-{
-	int err;
-
-	BUG_ON(!mutex_is_locked(&rng_mutex));
-
-	err = hwrng_init(rng);
-	if (err)
-		return err;
-
-	drop_current_rng();
-	current_rng = rng;
-
-	return 0;
-}
-
 /* Returns ERR_PTR(), NULL or refcounted hwrng */
 static struct hwrng *get_current_rng(void)
 {
@@ -220,6 +202,22 @@ static int hwrng_init(struct hwrng *rng)
 	return 0;
 }
 
+static int set_current_rng(struct hwrng *rng)
+{
+	int err;
+
+	BUG_ON(!mutex_is_locked(&rng_mutex));
+
+	err = hwrng_init(rng);
+	if (err)
+		return err;
+
+	drop_current_rng();
+	current_rng = rng;
+
+	return 0;
+}
+
 static int rng_dev_open(struct inode *inode, struct file *filp)
 {
 	/* enforce read-only access to this chrdev */
-- 
2.10.0

Re: [PATCH 0/4] Rearrange functions to remove forward declarations

[David Daney]

On 10/26/2017 08:34 AM, PrasannaKumar Muralidharan wrote:
> This patch series rearranges functions such that forward declarations
> becomes unnecessary. Remove those forward declaration.

Why?

The code churn and increase in difficulty of attribution are big 
drawbacks to this sort of patch set.


> 
> This patch series is boot tested without user space in qemu with
> CONFIG_HW_RANDOM=y.
> 
> PrasannaKumar Muralidharan (4):
>    hw_random: core: Remove forward declaration by rearranging code
>    hw_random: core: Rearranging rng_get_data to remove forward
>      declaration
>    hw_random: core: Rearranging start_khwrngd to remove forward
>      declaration
>    hw_random: core: Remove forward declaration of hwrng_init
> 
>   drivers/char/hw_random/core.c | 151 ++++++++++++++++++++----------------------
>   1 file changed, 72 insertions(+), 79 deletions(-)
> 

Re: [PATCH 0/4] Rearrange functions to remove forward declarations

[PrasannaKumar Muralidharan]

Hi David,

On 26 October 2017 at 22:18, David Daney <ddaney@caviumnetworks.com> wrote:
> On 10/26/2017 08:34 AM, PrasannaKumar Muralidharan wrote:
>>
>> This patch series rearranges functions such that forward declarations
>> becomes unnecessary. Remove those forward declaration.
>
>
> Why?
>
> The code churn and increase in difficulty of attribution are big drawbacks
> to this sort of patch set.

Completely agreed. I did understand there is little value in this
change. Wasn't sure whether such a patch is encouraged so gave a try.
I am fine with not taking the patch.

Regards,
PrasannaKumar