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[03/14] tty: n_tty: use 'retval' for writes' retvals

Message ID 20230816105822.3685-7-jirislaby@kernel.org
State New
Headers show
Series tty: n_tty: cleanup | expand

Commit Message

Jiri Slaby Aug. 16, 2023, 10:58 a.m. UTC
We have a separate misnomer 'c' to hold the retuned value from
tty->ops->write(). Instead, use already defined and properly typed
'retval'.

We have another variable 'num' to serve the same purpose in the OPOST
branch. We can use this 'retval' too. But just clear it in case of
EAGAIN.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/tty/n_tty.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

Comments

Ilpo Järvinen Aug. 16, 2023, 2:21 p.m. UTC | #1
On Wed, 16 Aug 2023, Jiri Slaby (SUSE) wrote:

> We have a separate misnomer 'c' to hold the retuned value from
> tty->ops->write(). Instead, use already defined and properly typed
> 'retval'.
> 
> We have another variable 'num' to serve the same purpose in the OPOST
> branch. We can use this 'retval' too. But just clear it in case of
> EAGAIN.
> 
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
>  drivers/tty/n_tty.c | 30 ++++++++++++++----------------
>  1 file changed, 14 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
> index f6fa4dbdf78f..e293d87b5362 100644
> --- a/drivers/tty/n_tty.c
> +++ b/drivers/tty/n_tty.c
> @@ -2335,7 +2335,6 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
>  {
>  	const u8 *b = buf;
>  	DEFINE_WAIT_FUNC(wait, woken_wake_function);
> -	int c;
>  	ssize_t retval = 0;
>  
>  	/* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
> @@ -2362,15 +2361,16 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
>  		}
>  		if (O_OPOST(tty)) {
>  			while (nr > 0) {
> -				ssize_t num = process_output_block(tty, b, nr);
> -				if (num < 0) {
> -					if (num == -EAGAIN)
> -						break;
> -					retval = num;
> -					goto break_out;
> +				retval = process_output_block(tty, b, nr);
> +				if (retval == -EAGAIN) {
> +					retval = 0;
> +					break;
>  				}
> -				b += num;
> -				nr -= num;
> +				if (retval < 0)
> +					goto break_out;
> +
> +				b += retval;
> +				nr -= retval;
>  				if (nr == 0)
>  					break;
>  				if (process_output(*b, tty) < 0)
> @@ -2384,16 +2384,14 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
>  
>  			while (nr > 0) {
>  				mutex_lock(&ldata->output_lock);
> -				c = tty->ops->write(tty, b, nr);
> +				retval = tty->ops->write(tty, b, nr);
>  				mutex_unlock(&ldata->output_lock);
> -				if (c < 0) {
> -					retval = c;
> +				if (retval < 0)
>  					goto break_out;
> -				}
> -				if (!c)
> +				if (!retval)
>  					break;
> -				b += c;
> -				nr -= c;
> +				b += retval;
> +				nr -= retval;

Type might be better but these two don't look like a major improvement... 
To me it seems obvious there exists some variable name that is better than 
c or retval for this purpose. ;-)
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Patch

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index f6fa4dbdf78f..e293d87b5362 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2335,7 +2335,6 @@  static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 {
 	const u8 *b = buf;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int c;
 	ssize_t retval = 0;
 
 	/* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
@@ -2362,15 +2361,16 @@  static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 		}
 		if (O_OPOST(tty)) {
 			while (nr > 0) {
-				ssize_t num = process_output_block(tty, b, nr);
-				if (num < 0) {
-					if (num == -EAGAIN)
-						break;
-					retval = num;
-					goto break_out;
+				retval = process_output_block(tty, b, nr);
+				if (retval == -EAGAIN) {
+					retval = 0;
+					break;
 				}
-				b += num;
-				nr -= num;
+				if (retval < 0)
+					goto break_out;
+
+				b += retval;
+				nr -= retval;
 				if (nr == 0)
 					break;
 				if (process_output(*b, tty) < 0)
@@ -2384,16 +2384,14 @@  static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 
 			while (nr > 0) {
 				mutex_lock(&ldata->output_lock);
-				c = tty->ops->write(tty, b, nr);
+				retval = tty->ops->write(tty, b, nr);
 				mutex_unlock(&ldata->output_lock);
-				if (c < 0) {
-					retval = c;
+				if (retval < 0)
 					goto break_out;
-				}
-				if (!c)
+				if (!retval)
 					break;
-				b += c;
-				nr -= c;
+				b += retval;
+				nr -= retval;
 			}
 		}
 		if (!nr)