* [PATCH] iio: core: fail early in iio_device_alloc() if we can't get a device id
@ 2020-04-16 12:33 Alexandru Ardelean
2020-04-18 15:25 ` Jonathan Cameron
0 siblings, 1 reply; 3+ messages in thread
From: Alexandru Ardelean @ 2020-04-16 12:33 UTC (permalink / raw)
To: linux-iio, linux-kernel; +Cc: jic23, Alexandru Ardelean
This change moves the 'ida_simple_get()' call to be the first one in
iio_device_alloc(). It cleans up the error path a bit as we don't need to
call any kfree(dev) anymore. We allocate an IIO device only if we have
managed to obtain a device ID.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/industrialio-core.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index f4daf19f2a3b..7c1d8a3ab2f3 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1494,6 +1494,14 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
{
struct iio_dev *dev;
size_t alloc_size;
+ int id;
+
+ id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
+ if (id < 0) {
+ /* cannot use a dev_err as the name isn't available */
+ pr_err("failed to get device id\n");
+ return NULL;
+ }
alloc_size = sizeof(struct iio_dev);
if (sizeof_priv) {
@@ -1506,6 +1514,8 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
dev = kzalloc(alloc_size, GFP_KERNEL);
if (dev) {
+ dev->id = id;
+ dev_set_name(&dev->dev, "iio:device%d", dev->id);
dev->dev.groups = dev->groups;
dev->dev.type = &iio_device_type;
dev->dev.bus = &iio_bus_type;
@@ -1514,15 +1524,6 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
mutex_init(&dev->mlock);
mutex_init(&dev->info_exist_lock);
INIT_LIST_HEAD(&dev->channel_attr_list);
-
- dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
- if (dev->id < 0) {
- /* cannot use a dev_err as the name isn't available */
- pr_err("failed to get device id\n");
- kfree(dev);
- return NULL;
- }
- dev_set_name(&dev->dev, "iio:device%d", dev->id);
INIT_LIST_HEAD(&dev->buffer_list);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] iio: core: fail early in iio_device_alloc() if we can't get a device id
2020-04-16 12:33 [PATCH] iio: core: fail early in iio_device_alloc() if we can't get a device id Alexandru Ardelean
@ 2020-04-18 15:25 ` Jonathan Cameron
2020-04-18 16:28 ` Ardelean, Alexandru
0 siblings, 1 reply; 3+ messages in thread
From: Jonathan Cameron @ 2020-04-18 15:25 UTC (permalink / raw)
To: Alexandru Ardelean; +Cc: linux-iio, linux-kernel
On Thu, 16 Apr 2020 15:33:31 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> This change moves the 'ida_simple_get()' call to be the first one in
> iio_device_alloc(). It cleans up the error path a bit as we don't need to
> call any kfree(dev) anymore. We allocate an IIO device only if we have
> managed to obtain a device ID.
We just threw away an ID if the kzalloc then fails (or am I missing something?)
With that fixed I can't see this as being much of an improvement.
Either way one allocation needs to be tidied up.
Jonathan
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
> drivers/iio/industrialio-core.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index f4daf19f2a3b..7c1d8a3ab2f3 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1494,6 +1494,14 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> {
> struct iio_dev *dev;
> size_t alloc_size;
> + int id;
> +
> + id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
> + if (id < 0) {
> + /* cannot use a dev_err as the name isn't available */
> + pr_err("failed to get device id\n");
> + return NULL;
> + }
>
> alloc_size = sizeof(struct iio_dev);
> if (sizeof_priv) {
> @@ -1506,6 +1514,8 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> dev = kzalloc(alloc_size, GFP_KERNEL);
>
> if (dev) {
> + dev->id = id;
> + dev_set_name(&dev->dev, "iio:device%d", dev->id);
> dev->dev.groups = dev->groups;
> dev->dev.type = &iio_device_type;
> dev->dev.bus = &iio_bus_type;
> @@ -1514,15 +1524,6 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> mutex_init(&dev->mlock);
> mutex_init(&dev->info_exist_lock);
> INIT_LIST_HEAD(&dev->channel_attr_list);
> -
> - dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
> - if (dev->id < 0) {
> - /* cannot use a dev_err as the name isn't available */
> - pr_err("failed to get device id\n");
> - kfree(dev);
> - return NULL;
> - }
> - dev_set_name(&dev->dev, "iio:device%d", dev->id);
> INIT_LIST_HEAD(&dev->buffer_list);
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] iio: core: fail early in iio_device_alloc() if we can't get a device id
2020-04-18 15:25 ` Jonathan Cameron
@ 2020-04-18 16:28 ` Ardelean, Alexandru
0 siblings, 0 replies; 3+ messages in thread
From: Ardelean, Alexandru @ 2020-04-18 16:28 UTC (permalink / raw)
To: jic23@kernel.org; +Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org
On Sat, 2020-04-18 at 16:25 +0100, Jonathan Cameron wrote:
> [External]
>
> On Thu, 16 Apr 2020 15:33:31 +0300
> Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
>
> > This change moves the 'ida_simple_get()' call to be the first one in
> > iio_device_alloc(). It cleans up the error path a bit as we don't need to
> > call any kfree(dev) anymore. We allocate an IIO device only if we have
> > managed to obtain a device ID.
>
> We just threw away an ID if the kzalloc then fails (or am I missing
> something?)
> With that fixed I can't see this as being much of an improvement.
> Either way one allocation needs to be tidied up.
oops,
the ida thingi eluded me when i wrote this;
apologies for the noise
>
> Jonathan
>
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> > ---
> > drivers/iio/industrialio-core.c | 19 ++++++++++---------
> > 1 file changed, 10 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-
> > core.c
> > index f4daf19f2a3b..7c1d8a3ab2f3 100644
> > --- a/drivers/iio/industrialio-core.c
> > +++ b/drivers/iio/industrialio-core.c
> > @@ -1494,6 +1494,14 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> > {
> > struct iio_dev *dev;
> > size_t alloc_size;
> > + int id;
> > +
> > + id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
> > + if (id < 0) {
> > + /* cannot use a dev_err as the name isn't available */
> > + pr_err("failed to get device id\n");
> > + return NULL;
> > + }
> >
> > alloc_size = sizeof(struct iio_dev);
> > if (sizeof_priv) {
> > @@ -1506,6 +1514,8 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> > dev = kzalloc(alloc_size, GFP_KERNEL);
> >
> > if (dev) {
> > + dev->id = id;
> > + dev_set_name(&dev->dev, "iio:device%d", dev->id);
> > dev->dev.groups = dev->groups;
> > dev->dev.type = &iio_device_type;
> > dev->dev.bus = &iio_bus_type;
> > @@ -1514,15 +1524,6 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
> > mutex_init(&dev->mlock);
> > mutex_init(&dev->info_exist_lock);
> > INIT_LIST_HEAD(&dev->channel_attr_list);
> > -
> > - dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
> > - if (dev->id < 0) {
> > - /* cannot use a dev_err as the name isn't available */
> > - pr_err("failed to get device id\n");
> > - kfree(dev);
> > - return NULL;
> > - }
> > - dev_set_name(&dev->dev, "iio:device%d", dev->id);
> > INIT_LIST_HEAD(&dev->buffer_list);
> > }
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-04-16 12:33 [PATCH] iio: core: fail early in iio_device_alloc() if we can't get a device id Alexandru Ardelean
2020-04-18 15:25 ` Jonathan Cameron
2020-04-18 16:28 ` Ardelean, Alexandru
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