[v4,1/3] devres: provide devm_krealloc()
diff mbox series

Message ID 20200713145934.18243-2-brgl@bgdev.pl
State New
Headers show
Series
  • devres: provide and use devm_krealloc()
Related show

Commit Message

Bartosz Golaszewski July 13, 2020, 2:59 p.m. UTC
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Implement the managed variant of krealloc(). This function works with
all memory allocated by devm_kmalloc() (or devres functions using it
implicitly like devm_kmemdup(), devm_kstrdup() etc.).

Managed realloc'ed chunks can be manually released with devm_kfree().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 .../driver-api/driver-model/devres.rst        |  1 +
 drivers/base/devres.c                         | 67 +++++++++++++++++++
 include/linux/device.h                        |  2 +
 3 files changed, 70 insertions(+)

Comments

Andy Shevchenko July 13, 2020, 7:29 p.m. UTC | #1
On Mon, Jul 13, 2020 at 04:59:32PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> Implement the managed variant of krealloc(). This function works with
> all memory allocated by devm_kmalloc() (or devres functions using it
> implicitly like devm_kmemdup(), devm_kstrdup() etc.).
> 
> Managed realloc'ed chunks can be manually released with devm_kfree().
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  .../driver-api/driver-model/devres.rst        |  1 +
>  drivers/base/devres.c                         | 67 +++++++++++++++++++
>  include/linux/device.h                        |  2 +
>  3 files changed, 70 insertions(+)
> 
> diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
> index eaaaafc21134f..f318a5c0033c1 100644
> --- a/Documentation/driver-api/driver-model/devres.rst
> +++ b/Documentation/driver-api/driver-model/devres.rst
> @@ -354,6 +354,7 @@ MEM
>    devm_kmalloc()
>    devm_kmalloc_array()
>    devm_kmemdup()
> +  devm_krealloc()
>    devm_kstrdup()
>    devm_kvasprintf()
>    devm_kzalloc()
> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> index ed615d3b9cf15..1775d35462300 100644
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -837,6 +837,73 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
>  }
>  EXPORT_SYMBOL_GPL(devm_kmalloc);
>  
> +/**
> + * devm_krealloc - Resource-managed krealloc()
> + * @dev: Device to re-allocate memory for
> + * @ptr: Pointer to the memory chunk to re-allocate
> + * @new_size: New allocation size
> + * @gfp: Allocation gfp flags
> + *
> + * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc().
> + * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR,
> + * it's the equivalent of devm_kmalloc(). If new_size is zero, it returns

'it frees the previously allocated memory and returns'

> + * ZERO_SIZE_PTR. This function doesn't change the order in which the release
> + * callback for the re-alloc'ed devres will be called (except when falling back
> + * to devm_kmalloc()

'or when freeing resources when new_size is zero'

> ). The contents of the memory are preserved up to the
> + * lesser of new and old sizes.
> + */
> +void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
> +{
> +	struct devres *old_dr, *new_dr;
> +	struct list_head old_head;
> +	unsigned long flags;
> +	size_t total_size;
> +	void *ret = NULL;
> +
> +	if (unlikely(!new_size)) {
> +		devm_kfree(dev, ptr);
> +		return ZERO_SIZE_PTR;
> +	}
> +
> +	if (unlikely(ZERO_OR_NULL_PTR(ptr)))
> +		return devm_kmalloc(dev, new_size, gfp);
> +
> +	if (WARN_ON(is_kernel_rodata((unsigned long)ptr)))
> +		/*
> +		 * We cannot reliably realloc a const string returned by
> +		 * devm_kstrdup_const().
> +		 */
> +		return NULL;
> +
> +	if (!check_dr_size(new_size, &total_size))
> +		return NULL;
> +
> +	spin_lock_irqsave(&dev->devres_lock, flags);
> +
> +	old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr);
> +	if (!old_dr) {
> +		spin_unlock_irqrestore(&dev->devres_lock, flags);
> +		WARN(1, "Memory chunk not managed or managed by a different device.");
> +		return NULL;
> +	}
> +
> +	old_head = old_dr->node.entry;
> +
> +	new_dr = krealloc(old_dr, total_size, gfp);
> +	if (!new_dr) {
> +		spin_unlock_irqrestore(&dev->devres_lock, flags);
> +		return NULL;
> +	}
> +
> +	if (new_dr != old_dr)
> +		list_replace(&old_head, &new_dr->node.entry);
> +
> +	ret = new_dr->data;
> +	spin_unlock_irqrestore(&dev->devres_lock, flags);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_krealloc);
> +
>  /**
>   * devm_kstrdup - Allocate resource managed space and
>   *                copy an existing string into that.
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 7322c51e9c0c7..f64f408431593 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -206,6 +206,8 @@ int devres_release_group(struct device *dev, void *id);
>  
>  /* managed devm_k.alloc/kfree for device drivers */
>  void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __malloc;

> +void *devm_krealloc(struct device *dev, void *ptr, size_t size,
> +		    gfp_t gfp) __must_check;

Strange indentation, also you can move __must_check to the beginning of the
declaration.


>  __printf(3, 0) char *devm_kvasprintf(struct device *dev, gfp_t gfp,
>  				     const char *fmt, va_list ap) __malloc;
>  __printf(3, 4) char *devm_kasprintf(struct device *dev, gfp_t gfp,
> -- 
> 2.26.1
>
Bartosz Golaszewski July 14, 2020, 2:48 p.m. UTC | #2
On Mon, Jul 13, 2020 at 9:29 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Mon, Jul 13, 2020 at 04:59:32PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> > Implement the managed variant of krealloc(). This function works with
> > all memory allocated by devm_kmalloc() (or devres functions using it
> > implicitly like devm_kmemdup(), devm_kstrdup() etc.).
> >
> > Managed realloc'ed chunks can be manually released with devm_kfree().
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > ---
> >  .../driver-api/driver-model/devres.rst        |  1 +
> >  drivers/base/devres.c                         | 67 +++++++++++++++++++
> >  include/linux/device.h                        |  2 +
> >  3 files changed, 70 insertions(+)
> >
> > diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
> > index eaaaafc21134f..f318a5c0033c1 100644
> > --- a/Documentation/driver-api/driver-model/devres.rst
> > +++ b/Documentation/driver-api/driver-model/devres.rst
> > @@ -354,6 +354,7 @@ MEM
> >    devm_kmalloc()
> >    devm_kmalloc_array()
> >    devm_kmemdup()
> > +  devm_krealloc()
> >    devm_kstrdup()
> >    devm_kvasprintf()
> >    devm_kzalloc()
> > diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> > index ed615d3b9cf15..1775d35462300 100644
> > --- a/drivers/base/devres.c
> > +++ b/drivers/base/devres.c
> > @@ -837,6 +837,73 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
> >  }
> >  EXPORT_SYMBOL_GPL(devm_kmalloc);
> >
> > +/**
> > + * devm_krealloc - Resource-managed krealloc()
> > + * @dev: Device to re-allocate memory for
> > + * @ptr: Pointer to the memory chunk to re-allocate
> > + * @new_size: New allocation size
> > + * @gfp: Allocation gfp flags
> > + *
> > + * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc().
> > + * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR,
> > + * it's the equivalent of devm_kmalloc(). If new_size is zero, it returns
>
> 'it frees the previously allocated memory and returns'
>
> > + * ZERO_SIZE_PTR. This function doesn't change the order in which the release
> > + * callback for the re-alloc'ed devres will be called (except when falling back
> > + * to devm_kmalloc()
>
> 'or when freeing resources when new_size is zero'
>

This is nit-picking but ok. :)

[snip!]

> > +++ b/include/linux/device.h
> > @@ -206,6 +206,8 @@ int devres_release_group(struct device *dev, void *id);
> >
> >  /* managed devm_k.alloc/kfree for device drivers */
> >  void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __malloc;
>
> > +void *devm_krealloc(struct device *dev, void *ptr, size_t size,
> > +                 gfp_t gfp) __must_check;
>
> Strange indentation, also you can move __must_check to the beginning of the
> declaration.
>

There's nothing wrong with this indentation, what do you mean?
__must_check is usually put at the end of the line.

[snip!]

Bart

Patch
diff mbox series

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index eaaaafc21134f..f318a5c0033c1 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -354,6 +354,7 @@  MEM
   devm_kmalloc()
   devm_kmalloc_array()
   devm_kmemdup()
+  devm_krealloc()
   devm_kstrdup()
   devm_kvasprintf()
   devm_kzalloc()
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index ed615d3b9cf15..1775d35462300 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -837,6 +837,73 @@  void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
 }
 EXPORT_SYMBOL_GPL(devm_kmalloc);
 
+/**
+ * devm_krealloc - Resource-managed krealloc()
+ * @dev: Device to re-allocate memory for
+ * @ptr: Pointer to the memory chunk to re-allocate
+ * @new_size: New allocation size
+ * @gfp: Allocation gfp flags
+ *
+ * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc().
+ * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR,
+ * it's the equivalent of devm_kmalloc(). If new_size is zero, it returns
+ * ZERO_SIZE_PTR. This function doesn't change the order in which the release
+ * callback for the re-alloc'ed devres will be called (except when falling back
+ * to devm_kmalloc()). The contents of the memory are preserved up to the
+ * lesser of new and old sizes.
+ */
+void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
+{
+	struct devres *old_dr, *new_dr;
+	struct list_head old_head;
+	unsigned long flags;
+	size_t total_size;
+	void *ret = NULL;
+
+	if (unlikely(!new_size)) {
+		devm_kfree(dev, ptr);
+		return ZERO_SIZE_PTR;
+	}
+
+	if (unlikely(ZERO_OR_NULL_PTR(ptr)))
+		return devm_kmalloc(dev, new_size, gfp);
+
+	if (WARN_ON(is_kernel_rodata((unsigned long)ptr)))
+		/*
+		 * We cannot reliably realloc a const string returned by
+		 * devm_kstrdup_const().
+		 */
+		return NULL;
+
+	if (!check_dr_size(new_size, &total_size))
+		return NULL;
+
+	spin_lock_irqsave(&dev->devres_lock, flags);
+
+	old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr);
+	if (!old_dr) {
+		spin_unlock_irqrestore(&dev->devres_lock, flags);
+		WARN(1, "Memory chunk not managed or managed by a different device.");
+		return NULL;
+	}
+
+	old_head = old_dr->node.entry;
+
+	new_dr = krealloc(old_dr, total_size, gfp);
+	if (!new_dr) {
+		spin_unlock_irqrestore(&dev->devres_lock, flags);
+		return NULL;
+	}
+
+	if (new_dr != old_dr)
+		list_replace(&old_head, &new_dr->node.entry);
+
+	ret = new_dr->data;
+	spin_unlock_irqrestore(&dev->devres_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_krealloc);
+
 /**
  * devm_kstrdup - Allocate resource managed space and
  *                copy an existing string into that.
diff --git a/include/linux/device.h b/include/linux/device.h
index 7322c51e9c0c7..f64f408431593 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -206,6 +206,8 @@  int devres_release_group(struct device *dev, void *id);
 
 /* managed devm_k.alloc/kfree for device drivers */
 void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __malloc;
+void *devm_krealloc(struct device *dev, void *ptr, size_t size,
+		    gfp_t gfp) __must_check;
 __printf(3, 0) char *devm_kvasprintf(struct device *dev, gfp_t gfp,
 				     const char *fmt, va_list ap) __malloc;
 __printf(3, 4) char *devm_kasprintf(struct device *dev, gfp_t gfp,