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Re: [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions

From Paul Bolle <pebolle@tiscali.nl>
Newsgroups linux.kernel
Subject Re: [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions
Date 2016-09-28 13:40 +0200
Message-ID <smlnr-63p-5@gated-at.bofh.it> (permalink)
References <qEuGl-43C-5@gated-at.bofh.it> <slGaB-5yk-1@gated-at.bofh.it> <slGaC-5yk-25@gated-at.bofh.it>
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On Mon, 2016-09-26 at 17:38 +0200, SF Markus Elfring wrote:
> * Multiplications for the size determination of memory allocations
>   indicated that array data structures should be processed.
>   Thus use the corresponding function "kmalloc_array".

Was the current code incorrect? What makes kmalloc_array() better? None
of this is obvious to me.

I'm not going to change code just because some checker suggests to do
so.

>   This issue was detected by using the Coccinelle software.

So? And which coccinelle script was actually used? I couldn't spot a
coccinelle script doing that in the current tree.

> * Replace the specification of a data structure by a pointer dereference
>   to make the corresponding size determination a bit safer according to
>   the Linux coding style convention.

I'm not happy with you mixing this with the above, less trivial,
change.

> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

> --- a/drivers/isdn/gigaset/common.c
> +++ b/drivers/isdn/gigaset/common.c
> @@ -709,8 +709,7 @@ struct cardstate *gigaset_initcs(struct gigaset_driver *drv, int channels,
>  
>  	cs->mode = M_UNKNOWN;
>  	cs->mstate = MS_UNINITIALIZED;
> -

Unrelated whitespace change.

> -	cs->bcs = kmalloc(channels * sizeof(struct bc_state), GFP_KERNEL);
> +	cs->bcs = kmalloc_array(channels, sizeof(*cs->bcs), GFP_KERNEL);

For the record: "channels" is basically hardcoded in the three gigaset
hardware drivers.

>  	cs->inbuf = kmalloc(sizeof(struct inbuf_t), GFP_KERNEL);
>  	if (!cs->bcs || !cs->inbuf) {
>  		pr_err("out of memory\n");
> @@ -1089,8 +1088,7 @@ struct gigaset_driver
> *gigaset_initdriver(unsigned minor, unsigned minors,
>  	drv->ops = ops;
>  	drv->owner = owner;
>  	INIT_LIST_HEAD(&drv->list);
> -

Again unrelated whitespace change.

> -	drv->cs = kmalloc(minors * sizeof *drv->cs, GFP_KERNEL);
> +	drv->cs = kmalloc_array(minors, sizeof(*drv->cs), GFP_KERNEL);

For "minors" the same holds as for "channels", above.

And you snuck in a parentheses change. That should have probably been
merged with 5/5.

>  	if (!drv->cs)
>  		goto error;


Paul Bolle

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Thread

[PATCH 0/5] ISDN-Gigaset: Fine-tuning for three function  implementations SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:40 +0200
  [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:40 +0200
    Re: [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions Paul Bolle <pebolle@tiscali.nl> - 2016-09-28 13:40 +0200
      Re: [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-28 18:50 +0200
        Re: [PATCH 1/5] ISDN-Gigaset: Use kmalloc_array() in two functions Paul Bolle <pebolle@tiscali.nl> - 2016-09-28 19:50 +0200
  [PATCH 2/5] ISDN-Gigaset: Improve another size determination in  gigaset_initcs() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:50 +0200
  [PATCH 4/5] ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:50 +0200
    Re: [PATCH 4/5] ISDN-Gigaset: Release memory in gigaset_initcs()  after an allocation failure Paul Bolle <pebolle@tiscali.nl> - 2016-09-26 23:20 +0200
      Re: ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 07:30 +0200
        Re: ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure Paul Bolle <pebolle@tiscali.nl> - 2016-09-27 10:50 +0200
          Re: ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 11:40 +0200
            Re: ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure Paul Bolle <pebolle@tiscali.nl> - 2016-09-27 11:50 +0200
            Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure Tilman Schmidt <tilman@imap.cc> - 2016-09-27 12:30 +0200
              Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 13:40 +0200
                Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure Tilman Schmidt <tilman@imap.cc> - 2016-09-27 14:10 +0200
                Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure isdn@linux-pingi.de - 2016-09-27 14:20 +0200
                Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 15:00 +0200
                Re: [Gigaset307x-common] ISDN-Gigaset: Release memory in  gigaset_initcs() after an allocation failure Tilman Schmidt <tilman@imap.cc> - 2016-09-27 16:40 +0200
      Re: [PATCH 4/5] ISDN-Gigaset: Release memory in gigaset_initcs()  after an allocation failure Dan Carpenter <dan.carpenter@oracle.com> - 2016-09-27 09:40 +0200
      Re: [PATCH 4/5] ISDN-Gigaset: Release memory in gigaset_initcs()  after an allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 17:20 +0200
    Re: [PATCH 4/5] ISDN-Gigaset: Release memory in gigaset_initcs()  after an allocation failure Dan Carpenter <dan.carpenter@oracle.com> - 2016-09-27 09:20 +0200
      Re: ISDN-Gigaset: Release memory in gigaset_initcs() after an  allocation failure SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 09:30 +0200
  [PATCH 3/5] ISDN-Gigaset: Delete an error message for a failed memory  allocation SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:50 +0200
    Re: [PATCH 3/5] ISDN-Gigaset: Delete an error message for a failed  memory allocation Tilman Schmidt <tilman@imap.cc> - 2016-09-27 13:00 +0200
      Re: [PATCH 3/5] ISDN-Gigaset: Delete an error message for a failed  memory allocation Paul Bolle <pebolle@tiscali.nl> - 2016-09-28 13:50 +0200
  [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 17:50 +0200
    RE: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses David Laight <David.Laight@ACULAB.COM> - 2016-09-26 18:10 +0200
      Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses Joe Perches <joe@perches.com> - 2016-09-26 18:30 +0200
        Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 18:50 +0200
          Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses Julia Lawall <julia.lawall@lip6.fr> - 2016-09-26 19:00 +0200
        [PATCH v2 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 19:50 +0200
          Re: [PATCH v2 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses Paul Bolle <pebolle@tiscali.nl> - 2016-09-26 20:40 +0200
            Re: [PATCH v2 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 20:50 +0200
          Re: [PATCH v2 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses David Miller <davem@davemloft.net> - 2016-09-27 02:20 +0200
            Re: [PATCH v2 5/5] ISDN-Gigaset: Enclose two expressions for the  sizeof operator by parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 07:40 +0200
    Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-09-26 19:40 +0200
      Re: ISDN-Gigaset: Enclose two expressions for the sizeof operator by  parentheses SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-26 20:10 +0200
        Re: ISDN-Gigaset: Enclose two expressions for the sizeof operator  by parentheses Paul Bolle <pebolle@tiscali.nl> - 2016-09-26 20:40 +0200
      Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses Dan Carpenter <dan.carpenter@oracle.com> - 2016-09-27 09:10 +0200
        Re: [PATCH 5/5] ISDN-Gigaset: Enclose two expressions for the sizeof  operator by parentheses Dan Carpenter <dan.carpenter@oracle.com> - 2016-09-27 09:30 +0200
  Re: [PATCH 0/5] ISDN-Gigaset: Fine-tuning for three function  implementations Paul Bolle <pebolle@tiscali.nl> - 2016-09-26 22:40 +0200
    Re: ISDN-Gigaset: Fine-tuning for three function implementations SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-27 07:20 +0200
  Re: [PATCH 0/5] ISDN-Gigaset: Fine-tuning for three function  implementations Paul Bolle <pebolle@tiscali.nl> - 2016-09-28 14:00 +0200
    Re: ISDN-Gigaset: Fine-tuning for three function implementations SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-28 19:00 +0200
      Re: ISDN-Gigaset: Fine-tuning for three function implementations Paul Bolle <pebolle@tiscali.nl> - 2016-09-28 20:00 +0200

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