On Mon, Jun 29, 2020 at 08:50:07AM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> > > 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@xxxxxxxxxxxx> > --- > .../driver-api/driver-model/devres.rst | 1 + > drivers/base/devres.c | 50 +++++++++++++++++++ > include/linux/device.h | 2 + > 3 files changed, 53 insertions(+) > > diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst > index e0b58c392e4f..0a2572c3813c 100644 > --- a/Documentation/driver-api/driver-model/devres.rst > +++ b/Documentation/driver-api/driver-model/devres.rst > @@ -352,6 +352,7 @@ MEM > devm_kfree() > devm_kmalloc() > devm_kmalloc_array() > + devm_krealloc() > devm_kmemdup() > devm_kstrdup() > devm_kvasprintf() > diff --git a/drivers/base/devres.c b/drivers/base/devres.c > index ed615d3b9cf1..4b8870ef6a3f 100644 > --- a/drivers/base/devres.c > +++ b/drivers/base/devres.c > @@ -837,6 +837,56 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) > } > EXPORT_SYMBOL_GPL(devm_kmalloc); > > +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; > + void *ret = NULL; > + size_t tot_size; > + > + 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, &tot_size)) > + return NULL; > + > + spin_lock_irqsave(&dev->devres_lock, flags); > + > + old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr); > + if (WARN_ON(!old_dr)) > + /* Memory chunk not managed or managed by a different device. */ > + goto out; > + > + old_head = old_dr->node.entry; > + > + new_dr = krealloc(old_dr, tot_size, gfp); > + if (!new_dr) > + goto out; > + > + if (new_dr != old_dr) > + list_replace(&old_head, &new_dr->node.entry); > + > + ret = new_dr->data; > + > +out: > + spin_unlock_irqrestore(&dev->devres_lock, flags); > + return ret; > +} > +EXPORT_SYMBOL_GPL(devm_krealloc); That's a lot of logic that does not seem to match up with the krealloc() logic in mm/slab_common.c, are you sure we need to do all of that? Who wants this? thanks, greg k-h