Documentation: adopt new coding style of type-aware kmalloc-family

Update the documentation to reflect new type-aware kmalloc-family as
suggested in commit 2932ba8d9c ("slab: Introduce kmalloc_obj()
and family")

ptr = kmalloc(sizeof(*ptr), gfp);
 -> ptr = kmalloc_obj(*ptr, gfp);
ptr = kmalloc(sizeof(struct some_obj_name), gfp);
 -> ptr = kmalloc_obj(*ptr, gfp);
ptr = kzalloc(sizeof(*ptr), gfp);
 -> ptr = kzalloc_obj(*ptr, gfp);
ptr = kmalloc_array(count, sizeof(*ptr), gfp);
 -> ptr = kmalloc_objs(*ptr, count, gfp);
ptr = kcalloc(count, sizeof(*ptr), gfp);
 -> ptr = kzalloc_objs(*ptr, count, gfp);

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260429071445.309733-2-manuelebner@mailbox.org>

Documentation/core-api/kref.rst

@@ -40,7 +40,7 @@ kref_init as so::
 
      struct my_data *data;
 
-     data = kmalloc(sizeof(*data), GFP_KERNEL);
+     data = kmalloc_obj(*data);
      if (!data)
             return -ENOMEM;
      kref_init(&data->refcount);
@@ -100,7 +100,7 @@ thread to process::
 	int rv = 0;
 	struct my_data *data;
 	struct task_struct *task;
-	data = kmalloc(sizeof(*data), GFP_KERNEL);
+	data = kmalloc_obj(*data);
 	if (!data)
 		return -ENOMEM;
 	kref_init(&data->refcount);

Documentation/core-api/list.rst

@@ -112,7 +112,7 @@ list:
 
           /* State 1 */
 
-          grock = kzalloc(sizeof(*grock), GFP_KERNEL);
+          grock = kzalloc_obj(*grock);
           if (!grock)
                   return -ENOMEM;
           grock->name = "Grock";
@@ -123,7 +123,7 @@ list:
 
           /* State 2 */
 
-          dimitri = kzalloc(sizeof(*dimitri), GFP_KERNEL);
+          dimitri = kzalloc_obj(*dimitri);
           if (!dimitri)
                   return -ENOMEM;
           dimitri->name = "Dimitri";

Documentation/driver-api/mailbox.rst

@@ -87,8 +87,8 @@ a message and a callback function to the API and return immediately).
 		struct async_pkt ap;
 		struct sync_pkt sp;
 
-		dc_sync = kzalloc(sizeof(*dc_sync), GFP_KERNEL);
+		dc_sync = kzalloc_obj(*dc_sync);
-		dc_async = kzalloc(sizeof(*dc_async), GFP_KERNEL);
+		dc_async = kzalloc_obj(*dc_async);
 
 		/* Populate non-blocking mode client */
 		dc_async->cl.dev = &pdev->dev;

Documentation/driver-api/media/v4l2-fh.rst

@@ -42,7 +42,7 @@ Example:
 
 		...
 
-		my_fh = kzalloc(sizeof(*my_fh), GFP_KERNEL);
+		my_fh = kzalloc_obj(*my_fh);
 
 		...
 

Documentation/kernel-hacking/locking.rst

@@ -442,7 +442,7 @@ to protect the cache and all the objects within it. Here's the code::
     {
             struct object *obj;
 
-            if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL)
+            if ((obj = kmalloc_obj(*obj)) == NULL)
                     return -ENOMEM;
 
             strscpy(obj->name, name, sizeof(obj->name));
@@ -517,7 +517,7 @@ which are taken away, and the ``+`` are lines which are added.
              struct object *obj;
     +        unsigned long flags;
 
-             if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL)
+             if ((obj = kmalloc_obj(*obj)) == NULL)
                      return -ENOMEM;
     @@ -63,30 +64,33 @@
              obj->id = id;

Documentation/locking/locktypes.rst

@@ -498,7 +498,7 @@ allocating memory.  Thus, on a non-PREEMPT_RT kernel the following code
 works perfectly::
 
   raw_spin_lock(&lock);
-  p = kmalloc(sizeof(*p), GFP_ATOMIC);
+  p = kmalloc_obj(*p, GFP_ATOMIC);
 
 But this code fails on PREEMPT_RT kernels because the memory allocator is
 fully preemptible and therefore cannot be invoked from truly atomic
@@ -507,7 +507,7 @@ while holding normal non-raw spinlocks because they do not disable
 preemption on PREEMPT_RT kernels::
 
   spin_lock(&lock);
-  p = kmalloc(sizeof(*p), GFP_ATOMIC);
+  p = kmalloc_obj(*p, GFP_ATOMIC);
 
 
 bit spinlocks

Documentation/process/coding-style.rst

@@ -936,7 +936,7 @@ used.
 ---------------------
 
 The kernel provides the following general purpose memory allocators:
-kmalloc(), kzalloc(), kmalloc_array(), kcalloc(), vmalloc(), and
+kmalloc(), kzalloc(), kmalloc_objs(), kzalloc_objs(), vmalloc(), and
 vzalloc().  Please refer to the API documentation for further information
 about them.  :ref:`Documentation/core-api/memory-allocation.rst
 <memory_allocation>`
@@ -945,7 +945,7 @@ The preferred form for passing a size of a struct is the following:
 
 .. code-block:: c
 
-	p = kmalloc(sizeof(*p), ...);
+	p = kmalloc_obj(*p, ...);
 
 The alternative form where struct name is spelled out hurts readability and
 introduces an opportunity for a bug when the pointer variable type is changed
@@ -959,13 +959,13 @@ The preferred form for allocating an array is the following:
 
 .. code-block:: c
 
-	p = kmalloc_array(n, sizeof(...), ...);
+	p = kmalloc_objs(*ptr, n, ...);
 
 The preferred form for allocating a zeroed array is the following:
 
 .. code-block:: c
 
-	p = kcalloc(n, sizeof(...), ...);
+	p = kzalloc_objs(*ptr, n, ...);
 
 Both forms check for overflow on the allocation size n * sizeof(...),
 and return NULL if that occurred.

Documentation/sound/kernel-api/writing-an-alsa-driver.rst

@@ -266,7 +266,7 @@ to details explained in the following section.
               ....
 
               /* allocate a chip-specific data with zero filled */
-              chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+              chip = kzalloc_obj(*chip);
               if (chip == NULL)
                       return -ENOMEM;
 
@@ -628,7 +628,7 @@ After allocating a card instance via :c:func:`snd_card_new()`
   err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,
                      0, &card);
   .....
-  chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+  chip = kzalloc_obj(*chip);
 
 The chip record should have the field to hold the card pointer at least,
 
@@ -747,7 +747,7 @@ destructor and PCI entries. Example code is shown first, below::
                       return -ENXIO;
               }
 
-              chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+              chip = kzalloc_obj(*chip);
               if (chip == NULL) {
                       pci_disable_device(pci);
                       return -ENOMEM;
@@ -1737,7 +1737,7 @@ callback::
   {
           struct my_pcm_data *data;
           ....
-          data = kmalloc(sizeof(*data), GFP_KERNEL);
+          data = kmalloc_obj(*data);
           substream->runtime->private_data = data;
           ....
   }
@@ -3301,7 +3301,7 @@ You can then pass any pointer value to the ``private_data``. If you
 assign private data, you should define a destructor, too. The
 destructor function is set in the ``private_free`` field::
 
-  struct mydata *p = kmalloc(sizeof(*p), GFP_KERNEL);
+  struct mydata *p = kmalloc_obj(*p);
   hw->private_data = p;
   hw->private_free = mydata_free;
 
@@ -3833,7 +3833,7 @@ chip data individually::
           err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,
                              0, &card);
           ....
-          chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+          chip = kzalloc_obj(*chip);
           ....
           card->private_data = chip;
           ....

Documentation/spi/spi-summary.rst

@@ -249,7 +249,7 @@ And SOC-specific utility code might look something like::
 	{
 		struct mysoc_spi_data *pdata2;
 
-		pdata2 = kmalloc(sizeof *pdata2, GFP_KERNEL);
+		pdata2 = kmalloc_obj(*pdata2);
 		*pdata2 = pdata;
 		...
 		if (n == 2) {
@@ -373,7 +373,7 @@ a bus (appearing under /sys/class/spi_master).
 			return -ENODEV;
 
 		/* get memory for driver's per-chip state */
-		chip = kzalloc(sizeof *chip, GFP_KERNEL);
+		chip = kzalloc(*chip);
 		if (!chip)
 			return -ENOMEM;
 		spi_set_drvdata(spi, chip);

Documentation/translations/it_IT/kernel-hacking/locking.rst

@@ -462,7 +462,7 @@ e tutti gli oggetti che contiene. Ecco il codice::
     {
             struct object *obj;
 
-            if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL)
+            if ((obj = kmalloc_obj(*obj)) == NULL)
                     return -ENOMEM;
 
             strscpy(obj->name, name, sizeof(obj->name));
@@ -537,7 +537,7 @@ sono quelle rimosse, mentre quelle ``+`` sono quelle aggiunte.
              struct object *obj;
     +        unsigned long flags;
 
-             if ((obj = kmalloc(sizeof(*obj), GFP_KERNEL)) == NULL)
+             if ((obj = kmalloc_obj(*obj)) == NULL)
                      return -ENOMEM;
     @@ -63,30 +64,33 @@
              obj->id = id;

Documentation/translations/it_IT/locking/locktypes.rst

@@ -488,7 +488,7 @@ o rwlock_t. Per esempio, la sezione critica non deve fare allocazioni di
 memoria. Su un kernel non-PREEMPT_RT il seguente codice funziona perfettamente::
 
   raw_spin_lock(&lock);
-  p = kmalloc(sizeof(*p), GFP_ATOMIC);
+  p = kmalloc_obj(*p, GFP_ATOMIC);
 
 Ma lo stesso codice non funziona su un kernel PREEMPT_RT perché l'allocatore di
 memoria può essere oggetto di prelazione e quindi non può essere chiamato in un
@@ -497,7 +497,7 @@ trattiene un blocco *non-raw* perché non disabilitano la prelazione sui kernel
 PREEMPT_RT::
 
   spin_lock(&lock);
-  p = kmalloc(sizeof(*p), GFP_ATOMIC);
+  p = kmalloc_obj(*p, GFP_ATOMIC);
 
 
 bit spinlocks

Documentation/translations/it_IT/process/coding-style.rst

@@ -943,7 +943,7 @@ Il modo preferito per passare la dimensione di una struttura è il seguente:
 
 .. code-block:: c
 
-	p = kmalloc(sizeof(*p), ...);
+	p = kmalloc_obj(*p, ...);
 
 La forma alternativa, dove il nome della struttura viene scritto interamente,
 peggiora la leggibilità e introduce possibili bachi quando il tipo di

Documentation/translations/sp_SP/process/coding-style.rst

@@ -955,7 +955,7 @@ La forma preferida para pasar el tamaño de una estructura es la siguiente:
 
 .. code-block:: c
 
-	p = kmalloc(sizeof(*p), ...);
+	p = kmalloc_obj(*p, ...);
 
 La forma alternativa donde se deletrea el nombre de la estructura perjudica
 la legibilidad, y presenta una oportunidad para un error cuando se cambia

Documentation/translations/zh_CN/core-api/kref.rst

@@ -52,7 +52,7 @@ kref可以出现在数据结构体中的任何地方。
 
      struct my_data *data;
 
-     data = kmalloc(sizeof(*data), GFP_KERNEL);
+     data = kmalloc_obj(*data);
      if (!data)
             return -ENOMEM;
      kref_init(&data->refcount);
@@ -106,7 +106,7 @@ Kref规则
 	int rv = 0;
 	struct my_data *data;
 	struct task_struct *task;
-	data = kmalloc(sizeof(*data), GFP_KERNEL);
+	data = kmalloc_obj(*data);
 	if (!data)
 		return -ENOMEM;
 	kref_init(&data->refcount);

Documentation/translations/zh_CN/process/coding-style.rst

@@ -813,7 +813,7 @@ Documentation/translations/zh_CN/core-api/memory-allocation.rst 。
 
 .. code-block:: c
 
-	p = kmalloc(sizeof(*p), ...);
+	p = kmalloc_obj(*p, ...);
 
 另外一种传递方式中，sizeof 的操作数是结构体的名字，这样会降低可读性，并且可能
 会引入 bug。有可能指针变量类型被改变时，而对应的传递给内存分配函数的 sizeof

Documentation/translations/zh_CN/video4linux/v4l2-framework.txt

@@ -799,7 +799,7 @@ int my_open(struct file *file)
 
 	...
 
-	my_fh = kzalloc(sizeof(*my_fh), GFP_KERNEL);
+	my_fh = kzalloc_obj(*my_fh);
 
 	...
 

Documentation/translations/zh_TW/process/coding-style.rst

@@ -827,7 +827,7 @@ Documentation/translations/zh_CN/core-api/memory-allocation.rst 。
 
 .. code-block:: c
 
-	p = kmalloc(sizeof(*p), ...);
+	p = kmalloc_obj(*p, ...);
 
 另外一種傳遞方式中，sizeof 的操作數是結構體的名字，這樣會降低可讀性，並且可能
 會引入 bug。有可能指針變量類型被改變時，而對應的傳遞給內存分配函數的 sizeof