[PATCH v2 0/3] Documentation: adopt new coding style of type-aware kmalloc-family

[PATCH v2 0/3] Documentation: adopt new coding style of type-aware kmalloc-family

[Manuel Ebner]

Update the documentation to reflect new type-aware kmalloc-family as
suggested in commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj() and family")

I have also thought about adding a few cases to checkpatch.pl, but this
will take me some time, and i don't know if i can do it.

 [v1] -> [v2]:
put RCU/* in a seperate patch [Patch 2/3]
Omit optional argument (GFP_KERNEL) as suggested by https://lwn.net/Articles/1062856/
deprecated.rst: change the argument gfp to optional [Patch 3/3]

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>

[PATCH v2 1/3] Documentation: adopt new coding style of type-aware kmalloc-family

[Manuel Ebner]

Update the documentation to reflect new type-aware kmalloc-family as
suggested in commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj() and family")

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

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
---
 Documentation/core-api/kref.rst                      |  4 ++--
 Documentation/core-api/list.rst                      |  4 ++--
 Documentation/core-api/memory-allocation.rst         |  4 ++--
 Documentation/driver-api/mailbox.rst                 |  4 ++--
 Documentation/driver-api/media/v4l2-fh.rst           |  2 +-
 Documentation/kernel-hacking/locking.rst             |  4 ++--
 Documentation/locking/locktypes.rst                  |  4 ++--
 Documentation/process/coding-style.rst               |  8 ++++----
 .../sound/kernel-api/writing-an-alsa-driver.rst      | 12 ++++++------
 Documentation/spi/spi-summary.rst                    |  4 ++--
 .../translations/it_IT/kernel-hacking/locking.rst    |  4 ++--
 .../translations/it_IT/locking/locktypes.rst         |  4 ++--
 .../translations/it_IT/process/coding-style.rst      |  2 +-
 .../translations/sp_SP/process/coding-style.rst      |  2 +-
 Documentation/translations/zh_CN/core-api/kref.rst   |  4 ++--
 .../translations/zh_CN/process/coding-style.rst      |  2 +-
 .../zh_CN/video4linux/v4l2-framework.txt             |  2 +-
 .../translations/zh_TW/process/coding-style.rst      |  2 +-
 18 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/Documentation/core-api/kref.rst b/Documentation/core-api/kref.rst
index 8db9ff03d952..1c14c036699d 100644
--- a/Documentation/core-api/kref.rst
+++ b/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);
diff --git a/Documentation/core-api/list.rst b/Documentation/core-api/list.rst
index 241464ca0549..86cd0a1b77ea 100644
--- a/Documentation/core-api/list.rst
+++ b/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";
diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst
index 0f19dd524323..8379775f17d3 100644
--- a/Documentation/core-api/memory-allocation.rst
+++ b/Documentation/core-api/memory-allocation.rst
@@ -135,7 +135,7 @@ Selecting memory allocator
 The most straightforward way to allocate memory is to use a function
 from the kmalloc() family. And, to be on the safe side it's best to use
 routines that set memory to zero, like kzalloc(). If you need to
-allocate memory for an array, there are kmalloc_array() and kcalloc()
+allocate memory for an array, there are kmalloc_objs() and kzalloc_objs()
 helpers. The helpers struct_size(), array_size() and array3_size() can
 be used to safely calculate object sizes without overflowing.
 
@@ -151,7 +151,7 @@ sizes, the alignment is guaranteed to be at least the largest power-of-two
 divisor of the size.
 
 Chunks allocated with kmalloc() can be resized with krealloc(). Similarly
-to kmalloc_array(): a helper for resizing arrays is provided in the form of
+to kmalloc_objs(): a helper for resizing arrays is provided in the form of
 krealloc_array().
 
 For large allocations you can use vmalloc() and vzalloc(), or directly
diff --git a/Documentation/driver-api/mailbox.rst b/Documentation/driver-api/mailbox.rst
index 463dd032b96c..4bcd73a99115 100644
--- a/Documentation/driver-api/mailbox.rst
+++ b/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_async = kzalloc(sizeof(*dc_async), GFP_KERNEL);
+		dc_sync = kzalloc_obj(*dc_sync);
+		dc_async = kzalloc_obj(*dc_async);
 
 		/* Populate non-blocking mode client */
 		dc_async->cl.dev = &pdev->dev;
diff --git a/Documentation/driver-api/media/v4l2-fh.rst b/Documentation/driver-api/media/v4l2-fh.rst
index a934caa483a4..38319130ebf5 100644
--- a/Documentation/driver-api/media/v4l2-fh.rst
+++ b/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);
 
 		...
 
diff --git a/Documentation/kernel-hacking/locking.rst b/Documentation/kernel-hacking/locking.rst
index dff0646a717b..d02e62367c4f 100644
--- a/Documentation/kernel-hacking/locking.rst
+++ b/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;
diff --git a/Documentation/locking/locktypes.rst b/Documentation/locking/locktypes.rst
index 37b6a5670c2f..ac1ad722a9e7 100644
--- a/Documentation/locking/locktypes.rst
+++ b/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
diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
index 35b381230f6e..a3bf75dc7c88 100644
--- a/Documentation/process/coding-style.rst
+++ b/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.
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
index 895752cbcedd..12433612aa9c 100644
--- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
+++ b/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;
           ....
diff --git a/Documentation/spi/spi-summary.rst b/Documentation/spi/spi-summary.rst
index 6e21e6f86912..7ad6af76c247 100644
--- a/Documentation/spi/spi-summary.rst
+++ b/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);
diff --git a/Documentation/translations/it_IT/kernel-hacking/locking.rst b/Documentation/translations/it_IT/kernel-hacking/locking.rst
index 4c21cf60f775..acca89a3743a 100644
--- a/Documentation/translations/it_IT/kernel-hacking/locking.rst
+++ b/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;
diff --git a/Documentation/translations/it_IT/locking/locktypes.rst b/Documentation/translations/it_IT/locking/locktypes.rst
index 1c7056283b9d..d5fa36aa05cc 100644
--- a/Documentation/translations/it_IT/locking/locktypes.rst
+++ b/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
diff --git a/Documentation/translations/it_IT/process/coding-style.rst b/Documentation/translations/it_IT/process/coding-style.rst
index c0dc786b8474..2a499412a2e3 100644
--- a/Documentation/translations/it_IT/process/coding-style.rst
+++ b/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
diff --git a/Documentation/translations/sp_SP/process/coding-style.rst b/Documentation/translations/sp_SP/process/coding-style.rst
index 7d63aa8426e6..44c93d5f6beb 100644
--- a/Documentation/translations/sp_SP/process/coding-style.rst
+++ b/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
diff --git a/Documentation/translations/zh_CN/core-api/kref.rst b/Documentation/translations/zh_CN/core-api/kref.rst
index b9902af310c5..fcff01e99852 100644
--- a/Documentation/translations/zh_CN/core-api/kref.rst
+++ b/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);
diff --git a/Documentation/translations/zh_CN/process/coding-style.rst b/Documentation/translations/zh_CN/process/coding-style.rst
index 5a342a024c01..55d5da974d89 100644
--- a/Documentation/translations/zh_CN/process/coding-style.rst
+++ b/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
diff --git a/Documentation/translations/zh_CN/video4linux/v4l2-framework.txt b/Documentation/translations/zh_CN/video4linux/v4l2-framework.txt
index f0be21a60a0f..ba43c5c4797c 100644
--- a/Documentation/translations/zh_CN/video4linux/v4l2-framework.txt
+++ b/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);
 
 	...
 
diff --git a/Documentation/translations/zh_TW/process/coding-style.rst b/Documentation/translations/zh_TW/process/coding-style.rst
index e2ba97b3d8bb..63c78982a1af 100644
--- a/Documentation/translations/zh_TW/process/coding-style.rst
+++ b/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
-- 
2.53.0

[PATCH v2 2/3] Documentation: RCU: adopt new coding style of type-aware kmalloc-family

[Manuel Ebner]

Update Documentation/RCU/* to reflect new type-aware kmalloc-family as
suggested in commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj() and family")

ptr = kmalloc(sizeof(*ptr), gfp);
 -> ptr = kmalloc_obj(*ptr);

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
---
 Documentation/RCU/Design/Requirements/Requirements.rst | 6 +++---
 Documentation/RCU/listRCU.rst                          | 2 +-
 Documentation/RCU/whatisRCU.rst                        | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst
index b5cdbba3ec2e..faca5a9c8c12 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.rst
+++ b/Documentation/RCU/Design/Requirements/Requirements.rst
@@ -206,7 +206,7 @@ non-\ ``NULL``, locklessly accessing the ``->a`` and ``->b`` fields.
 
        1 bool add_gp_buggy(int a, int b)
        2 {
-       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
+       3   p = kmalloc_obj(*p);
        4   if (!p)
        5     return -ENOMEM;
        6   spin_lock(&gp_lock);
@@ -228,7 +228,7 @@ their rights to reorder this code as follows:
 
        1 bool add_gp_buggy_optimized(int a, int b)
        2 {
-       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
+       3   p = kmalloc_obj(*p);
        4   if (!p)
        5     return -ENOMEM;
        6   spin_lock(&gp_lock);
@@ -264,7 +264,7 @@ shows an example of insertion:
 
        1 bool add_gp(int a, int b)
        2 {
-       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
+       3   p = kmalloc_obj(*p);
        4   if (!p)
        5     return -ENOMEM;
        6   spin_lock(&gp_lock);
diff --git a/Documentation/RCU/listRCU.rst b/Documentation/RCU/listRCU.rst
index d8bb98623c12..48c7272a4ccc 100644
--- a/Documentation/RCU/listRCU.rst
+++ b/Documentation/RCU/listRCU.rst
@@ -276,7 +276,7 @@ The RCU version of audit_upd_rule() is as follows::
 
 		list_for_each_entry(e, list, list) {
 			if (!audit_compare_rule(rule, &e->rule)) {
-				ne = kmalloc(sizeof(*entry), GFP_ATOMIC);
+				ne = kmalloc_obj(*entry, GFP_ATOMIC);
 				if (ne == NULL)
 					return -ENOMEM;
 				audit_copy_rule(&ne->rule, &e->rule);
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
index a1582bd653d1..770aab8ea36a 100644
--- a/Documentation/RCU/whatisRCU.rst
+++ b/Documentation/RCU/whatisRCU.rst
@@ -468,7 +468,7 @@ uses of RCU may be found in listRCU.rst and NMI-RCU.rst.
 		struct foo *new_fp;
 		struct foo *old_fp;
 
-		new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
+		new_fp = kmalloc_obj(*new_fp);
 		spin_lock(&foo_mutex);
 		old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
 		*new_fp = *old_fp;
@@ -570,7 +570,7 @@ The foo_update_a() function might then be written as follows::
 		struct foo *new_fp;
 		struct foo *old_fp;
 
-		new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
+		new_fp = kmalloc_obj(*new_fp);
 		spin_lock(&foo_mutex);
 		old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
 		*new_fp = *old_fp;
-- 
2.53.0

[PATCH v2 3/3] Documentation: deprecated.rst: kmalloc-family: mark argument as optional

[Manuel Ebner]

put the optional argument (gfp) in square brackets

eg. ptr = kmalloc_obj(*ptr, gfp);
 -> ptr = kmalloc_obj(*ptr, [gfp]);

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
---
 Documentation/process/deprecated.rst | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
index fed56864d036..b431993fd08e 100644
--- a/Documentation/process/deprecated.rst
+++ b/Documentation/process/deprecated.rst
@@ -392,12 +392,12 @@ allocations. For example, these open coded assignments::
 
 become, respectively::
 
-	ptr = kmalloc_obj(*ptr, gfp);
-	ptr = kzalloc_obj(*ptr, gfp);
-	ptr = kmalloc_objs(*ptr, count, gfp);
-	ptr = kzalloc_objs(*ptr, count, gfp);
-	ptr = kmalloc_flex(*ptr, flex_member, count, gfp);
-	__auto_type ptr = kmalloc_obj(struct foo, gfp);
+	ptr = kmalloc_obj(*ptr, [gfp]);
+	ptr = kzalloc_obj(*ptr, [gfp]);
+	ptr = kmalloc_objs(*ptr, count, [gfp]);
+	ptr = kzalloc_objs(*ptr, count, [gfp]);
+	ptr = kmalloc_flex(*ptr, flex_member, count, [gfp]);
+	__auto_type ptr = kmalloc_obj(struct foo, [gfp]);
 
 If `ptr->flex_member` is annotated with __counted_by(), the allocation
 will automatically fail if `count` is larger than the maximum
-- 
2.53.0

Re: [PATCH v2 2/3] Documentation: RCU: adopt new coding style of type-aware kmalloc-family

[Paul E. McKenney]

On Tue, Apr 21, 2026 at 08:06:53PM +0200, Manuel Ebner wrote:
> Update Documentation/RCU/* to reflect new type-aware kmalloc-family as
> suggested in commit 2932ba8d9c99 ("slab: Introduce kmalloc_obj() and family")
> 
> ptr = kmalloc(sizeof(*ptr), gfp);
>  -> ptr = kmalloc_obj(*ptr);
> 
> Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>

Acked-by: Paul E. McKenney <paulmck@kernel.org>

> ---
>  Documentation/RCU/Design/Requirements/Requirements.rst | 6 +++---
>  Documentation/RCU/listRCU.rst                          | 2 +-
>  Documentation/RCU/whatisRCU.rst                        | 4 ++--
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst
> index b5cdbba3ec2e..faca5a9c8c12 100644
> --- a/Documentation/RCU/Design/Requirements/Requirements.rst
> +++ b/Documentation/RCU/Design/Requirements/Requirements.rst
> @@ -206,7 +206,7 @@ non-\ ``NULL``, locklessly accessing the ``->a`` and ``->b`` fields.
>  
>         1 bool add_gp_buggy(int a, int b)
>         2 {
> -       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
> +       3   p = kmalloc_obj(*p);
>         4   if (!p)
>         5     return -ENOMEM;
>         6   spin_lock(&gp_lock);
> @@ -228,7 +228,7 @@ their rights to reorder this code as follows:
>  
>         1 bool add_gp_buggy_optimized(int a, int b)
>         2 {
> -       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
> +       3   p = kmalloc_obj(*p);
>         4   if (!p)
>         5     return -ENOMEM;
>         6   spin_lock(&gp_lock);
> @@ -264,7 +264,7 @@ shows an example of insertion:
>  
>         1 bool add_gp(int a, int b)
>         2 {
> -       3   p = kmalloc(sizeof(*p), GFP_KERNEL);
> +       3   p = kmalloc_obj(*p);
>         4   if (!p)
>         5     return -ENOMEM;
>         6   spin_lock(&gp_lock);
> diff --git a/Documentation/RCU/listRCU.rst b/Documentation/RCU/listRCU.rst
> index d8bb98623c12..48c7272a4ccc 100644
> --- a/Documentation/RCU/listRCU.rst
> +++ b/Documentation/RCU/listRCU.rst
> @@ -276,7 +276,7 @@ The RCU version of audit_upd_rule() is as follows::
>  
>  		list_for_each_entry(e, list, list) {
>  			if (!audit_compare_rule(rule, &e->rule)) {
> -				ne = kmalloc(sizeof(*entry), GFP_ATOMIC);
> +				ne = kmalloc_obj(*entry, GFP_ATOMIC);
>  				if (ne == NULL)
>  					return -ENOMEM;
>  				audit_copy_rule(&ne->rule, &e->rule);
> diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
> index a1582bd653d1..770aab8ea36a 100644
> --- a/Documentation/RCU/whatisRCU.rst
> +++ b/Documentation/RCU/whatisRCU.rst
> @@ -468,7 +468,7 @@ uses of RCU may be found in listRCU.rst and NMI-RCU.rst.
>  		struct foo *new_fp;
>  		struct foo *old_fp;
>  
> -		new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
> +		new_fp = kmalloc_obj(*new_fp);
>  		spin_lock(&foo_mutex);
>  		old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
>  		*new_fp = *old_fp;
> @@ -570,7 +570,7 @@ The foo_update_a() function might then be written as follows::
>  		struct foo *new_fp;
>  		struct foo *old_fp;
>  
> -		new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
> +		new_fp = kmalloc_obj(*new_fp);
>  		spin_lock(&foo_mutex);
>  		old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
>  		*new_fp = *old_fp;
> -- 
> 2.53.0
> 
> 

Re: [PATCH v2 1/3] Documentation: adopt new coding style of type-aware kmalloc-family

[Matthew Wilcox]

On Tue, Apr 21, 2026 at 08:01:58PM +0200, Manuel Ebner wrote:
> +++ b/Documentation/core-api/memory-allocation.rst
> @@ -135,7 +135,7 @@ Selecting memory allocator
>  The most straightforward way to allocate memory is to use a function
>  from the kmalloc() family. And, to be on the safe side it's best to use
>  routines that set memory to zero, like kzalloc(). If you need to
> -allocate memory for an array, there are kmalloc_array() and kcalloc()
> +allocate memory for an array, there are kmalloc_objs() and kzalloc_objs()
>  helpers. The helpers struct_size(), array_size() and array3_size() can
>  be used to safely calculate object sizes without overflowing.

This seems to have been done without any thought.  kmalloc_array() still
exists and has over 500 callers.  It should not be de-documented.

> @@ -151,7 +151,7 @@ sizes, the alignment is guaranteed to be at least the largest power-of-two
>  divisor of the size.
>  
>  Chunks allocated with kmalloc() can be resized with krealloc(). Similarly
> -to kmalloc_array(): a helper for resizing arrays is provided in the form of
> +to kmalloc_objs(): a helper for resizing arrays is provided in the form of
>  krealloc_array().

Think about why this is wrong too.

And you should have cc'd linux-mm on this.

Re: [PATCH v2 1/3] Documentation: adopt new coding style of type-aware kmalloc-family

[Manuel Ebner]

On Tue, 2026-04-21 at 20:24 +0100, Matthew Wilcox wrote:
> On Tue, Apr 21, 2026 at 08:01:58PM +0200, Manuel Ebner wrote:
> > +++ b/Documentation/core-api/memory-allocation.rst
> > @@ -135,7 +135,7 @@ Selecting memory allocator
> >  The most straightforward way to allocate memory is to use a function
> >  from the kmalloc() family. And, to be on the safe side it's best to use
> >  routines that set memory to zero, like kzalloc(). If you need to
> > -allocate memory for an array, there are kmalloc_array() and kcalloc()
> > +allocate memory for an array, there are kmalloc_objs() and kzalloc_objs()
> >  helpers. The helpers struct_size(), array_size() and array3_size() can
> >  be used to safely calculate object sizes without overflowing.
> 
> This seems to have been done without any thought.  kmalloc_array() still
> exists and has over 500 callers.  It should not be de-documented.

you are right

> > @@ -151,7 +151,7 @@ sizes, the alignment is guaranteed to be at least the
> > largest power-of-two
> >  divisor of the size.
> >  
> >  Chunks allocated with kmalloc() can be resized with krealloc(). Similarly
> > -to kmalloc_array(): a helper for resizing arrays is provided in the form of
> > +to kmalloc_objs(): a helper for resizing arrays is provided in the form of
> >  krealloc_array().
> 
> Think about why this is wrong too.

i see now.

> And you should have cc'd linux-mm on this.

will add in [v3]

thanks,

manuel

Re: [PATCH v2 3/3] Documentation: deprecated.rst: kmalloc-family: mark argument as optional

[Geert Uytterhoeven]

Hi Manuel,

Thanks for your patch!

On Tue, 21 Apr 2026 at 20:09, Manuel Ebner <manuelebner@mailbox.org> wrote:
> put the optional argument (gfp) in square brackets
>
> eg. ptr = kmalloc_obj(*ptr, gfp);
>  -> ptr = kmalloc_obj(*ptr, [gfp]);

Shouldn't that be "[, gfp]", e.g.

    kmalloc_obj(*ptr [, gfp]);

everywhere?

> Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2 3/3] Documentation: deprecated.rst: kmalloc-family: mark argument as optional

[Manuel Ebner]

On Wed, 2026-04-22 at 09:14 +0200, Geert Uytterhoeven wrote:
> Hi Manuel,
> 
> Thanks for your patch!

That's good to read.

> On Tue, 21 Apr 2026 at 20:09, Manuel Ebner <manuelebner@mailbox.org> wrote:
> > put the optional argument (gfp) in square brackets
> > 
> > eg. ptr = kmalloc_obj(*ptr, gfp);
> >  -> ptr = kmalloc_obj(*ptr, [gfp]);
> 
> Shouldn't that be "[, gfp]", e.g.
> 
>     kmalloc_obj(*ptr [, gfp]);

I think technically it should be 

    kmalloc_obj(*ptr[, gfp]);

but that's difficult to grasp, so i went for my notation. Yours
is a good tradeoff. I'll think about it and choose the right one.

> 
> everywhere?
> 
> > Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
> 
> Gr{oetje,eeting}s,
> 
>                         Geert

Re: [PATCH v2 3/3] Documentation: deprecated.rst: kmalloc-family: mark argument as optional

[Geert Uytterhoeven]

Hi Manuel,

On Wed, 22 Apr 2026 at 14:10, Manuel Ebner <manuelebner@mailbox.org> wrote:
> On Wed, 2026-04-22 at 09:14 +0200, Geert Uytterhoeven wrote:
> > On Tue, 21 Apr 2026 at 20:09, Manuel Ebner <manuelebner@mailbox.org> wrote:
> > > put the optional argument (gfp) in square brackets
> > >
> > > eg. ptr = kmalloc_obj(*ptr, gfp);
> > >  -> ptr = kmalloc_obj(*ptr, [gfp]);
> >
> > Shouldn't that be "[, gfp]", e.g.
> >
> >     kmalloc_obj(*ptr [, gfp]);
>
> I think technically it should be
>
>     kmalloc_obj(*ptr[, gfp]);
>
> but that's difficult to grasp, so i went for my notation. Yours
> is a good tradeoff. I'll think about it and choose the right one.

A third option is

    kmalloc_obj(*ptr [, gfp] );

or even:

    kmalloc_obj(*ptr [ , gfp ] );

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds