2007-01-05 23:56:25

by Ahmed S. Darwish

[permalink] [raw]
Subject: [PATCH 2.6.20-rc3] TTY_IO code cleanups

Hi all,

>From Alan:
> if you can send me a patch for the tty_io/tty_ioctl code which
> switches to kzalloc where it makes sense and removes un-needed casts I'll
> review it and push the bits that look sane upstream.

Cleanups to switch kmalloc->kzalloc and to remove little redundant code found
(including the k[mz]alloc casts).

Thanks for your time.

Signed-off-by: Ahmed Darwish <[email protected]>

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 47a6eac..7b42c55 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -331,7 +331,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
p->next = NULL;
p->commit = 0;
p->read = 0;
- p->char_buf_ptr = (char *)(p->data);
+ p->char_buf_ptr = (char *)p->data;
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
tty->buf.memory_used += size;
return p;
@@ -640,7 +640,6 @@ static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */
int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
{
unsigned long flags;
- int ret = 0;

if (disc < N_TTY || disc >= NR_LDISCS)
return -EINVAL;
@@ -652,7 +651,7 @@ int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
tty_ldiscs[disc].refcount = 0;
spin_unlock_irqrestore(&tty_ldisc_lock, flags);

- return ret;
+ return 0;
}
EXPORT_SYMBOL(tty_register_ldisc);

@@ -791,17 +790,15 @@ static int tty_ldisc_try(struct tty_struct *tty)
{
unsigned long flags;
struct tty_ldisc *ld;
- int ret = 0;

spin_lock_irqsave(&tty_ldisc_lock, flags);
ld = &tty->ldisc;
- if(test_bit(TTY_LDISC, &tty->flags))
- {
+ if(test_bit(TTY_LDISC, &tty->flags)) {
ld->refcount++;
- ret = 1;
+ return 1;
}
spin_unlock_irqrestore(&tty_ldisc_lock, flags);
- return ret;
+ return 0;
}

/**
@@ -1932,19 +1929,16 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*tp_loc) {
- tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!tp)
goto free_mem_out;
*tp = driver->init_termios;
}

if (!*ltp_loc) {
- ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!ltp)
goto free_mem_out;
- memset(ltp, 0, sizeof(struct ktermios));
}

if (driver->type == TTY_DRIVER_TYPE_PTY) {
@@ -1965,19 +1959,16 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*o_tp_loc) {
- o_tp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_tp)
goto free_mem_out;
*o_tp = driver->other->init_termios;
}

if (!*o_ltp_loc) {
- o_ltp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_ltp)
goto free_mem_out;
- memset(o_ltp, 0, sizeof(struct ktermios));
}

/*
@@ -3605,9 +3596,8 @@ struct tty_driver *alloc_tty_driver(int lines)
{
struct tty_driver *driver;

- driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL);
+ driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
if (driver) {
- memset(driver, 0, sizeof(struct tty_driver));
driver->magic = TTY_DRIVER_MAGIC;
driver->num = lines;
/* later we'll move allocation of tables here */
@@ -3667,10 +3657,9 @@ int tty_register_driver(struct tty_driver *driver)
return 0;

if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
- p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
+ p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
if (!p)
return -ENOMEM;
- memset(p, 0, driver->num * 3 * sizeof(void *));
}

if (!driver->major) {


--
Ahmed S. Darwish
http://darwish-07.blogspot.com


2007-01-06 00:00:41

by David Rientjes

[permalink] [raw]
Subject: Re: [PATCH 2.6.20-rc3] TTY_IO code cleanups

On Sat, 6 Jan 2007, Ahmed S. Darwish wrote:

> @@ -791,17 +790,15 @@ static int tty_ldisc_try(struct tty_struct *tty)
> {
> unsigned long flags;
> struct tty_ldisc *ld;
> - int ret = 0;
>
> spin_lock_irqsave(&tty_ldisc_lock, flags);
> ld = &tty->ldisc;
> - if(test_bit(TTY_LDISC, &tty->flags))
> - {
> + if(test_bit(TTY_LDISC, &tty->flags)) {
> ld->refcount++;
> - ret = 1;
> + return 1;
> }
> spin_unlock_irqrestore(&tty_ldisc_lock, flags);
> - return ret;
> + return 0;
> }
>
> /**

You leave tty_ldisk_lock locked.

2007-01-06 00:08:46

by Ahmed S. Darwish

[permalink] [raw]
Subject: Re: [PATCH 2.6.20-rc3] TTY_IO code cleanups

> Signed-off-by: Ahmed Darwish <[email protected]>
> struct tty_ldisc *ld;
>- int ret = 0;
>
> spin_lock_irqsave(&tty_ldisc_lock, flags);
> ld = &tty->ldisc;
>- if(test_bit(TTY_LDISC, &tty->flags))
>- {
>+ if(test_bit(TTY_LDISC, &tty->flags)) {
> ld->refcount++;
>- ret = 1;
>+ return 1;
> }
> spin_unlock_irqrestore(&tty_ldisc_lock, flags);
>- return ret;
>+ return 0;
> }

Very sorry, Didn't mention the spin_unlock_irqrestore().
Here's the modified patch without this hunk.

Signed-off-by: Ahmed S. Darwish

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 47a6eac..9da9537 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -331,7 +331,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
p->next = NULL;
p->commit = 0;
p->read = 0;
- p->char_buf_ptr = (char *)(p->data);
+ p->char_buf_ptr = (char *)p->data;
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
tty->buf.memory_used += size;
return p;
@@ -640,7 +640,6 @@ static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */
int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
{
unsigned long flags;
- int ret = 0;

if (disc < N_TTY || disc >= NR_LDISCS)
return -EINVAL;
@@ -652,7 +651,7 @@ int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
tty_ldiscs[disc].refcount = 0;
spin_unlock_irqrestore(&tty_ldisc_lock, flags);

- return ret;
+ return 0;
}
EXPORT_SYMBOL(tty_register_ldisc);

@@ -1932,19 +1931,16 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*tp_loc) {
- tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!tp)
goto free_mem_out;
*tp = driver->init_termios;
}

if (!*ltp_loc) {
- ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
- GFP_KERNEL);
+ ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!ltp)
goto free_mem_out;
- memset(ltp, 0, sizeof(struct ktermios));
}

if (driver->type == TTY_DRIVER_TYPE_PTY) {
@@ -1965,19 +1961,16 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*o_tp_loc) {
- o_tp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_tp)
goto free_mem_out;
*o_tp = driver->other->init_termios;
}

if (!*o_ltp_loc) {
- o_ltp = (struct ktermios *)
- kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_ltp)
goto free_mem_out;
- memset(o_ltp, 0, sizeof(struct ktermios));
}

/*
@@ -3605,9 +3598,8 @@ struct tty_driver *alloc_tty_driver(int lines)
{
struct tty_driver *driver;

- driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL);
+ driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
if (driver) {
- memset(driver, 0, sizeof(struct tty_driver));
driver->magic = TTY_DRIVER_MAGIC;
driver->num = lines;
/* later we'll move allocation of tables here */
@@ -3667,10 +3659,9 @@ int tty_register_driver(struct tty_driver *driver)
return 0;

if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
- p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
+ p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
if (!p)
return -ENOMEM;
- memset(p, 0, driver->num * 3 * sizeof(void *));
}

if (!driver->major) {

--
Ahmed S. Darwish
http://darwish-07.blogspot.com

2007-01-06 14:40:00

by Jan Engelhardt

[permalink] [raw]
Subject: Re: [PATCH 2.6.20-rc3] TTY_IO code cleanups


On Jan 5 2007 16:00, David Rientjes wrote:
>> @@ -791,17 +790,15 @@ static int tty_ldisc_try(struct tty_struct *tty)
>> {
>> unsigned long flags;
>> struct tty_ldisc *ld;
>> - int ret = 0;
>>
>> spin_lock_irqsave(&tty_ldisc_lock, flags);
>> ld = &tty->ldisc;
>> - if(test_bit(TTY_LDISC, &tty->flags))
>> - {
>> + if(test_bit(TTY_LDISC, &tty->flags)) {
>> ld->refcount++;
>> - ret = 1;
>> + return 1;
>> }
>> spin_unlock_irqrestore(&tty_ldisc_lock, flags);
>> - return ret;
>> + return 0;
>> }
>>
>> /**
>
>You leave tty_ldisk_lock locked.

Hence it was not redundant. Either way,

if(test_bit(...)) {
spin_unlock_irqrestore(..)
return 1;
}

would probably generate the same ASM as the original, hence it is not
really an improvement.


-`J'
--