linux-kernel - Re: [PATCH] Coccinelle: kzalloc-simple: Add all zero allocating functions

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Date:   Sun, 24 Dec 2017 12:59:32 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     Himanshu Jha <himanshujha199640@...il.com>
cc:     Julia Lawall <Julia.Lawall@...6.fr>,
        Gilles Muller <Gilles.Muller@...6.fr>, nicolas.palix@...g.fr,
        michal.lkml@...kovi.net, cocci@...teme.lip6.fr,
        linux-kernel@...r.kernel.org, mcgrof@...nel.org
Subject: Re: [PATCH] Coccinelle: kzalloc-simple: Add all zero allocating
 functions



On Sun, 24 Dec 2017, Himanshu Jha wrote:

> There are many instances where memory is allocated using regular allocator
> functions immediately followed by setting the allocated memory
> to 0 value using memset.
>
> We already have zero memory allocator functions to set the memory to
> 0 value instead of manually setting it using memset.
>
> Therefore, use zero memory allocating functions instead of regular
> memory allocators followed by memset 0 to remove redundant memset and
> make the code more cleaner and also reduce the code size.
>
> Signed-off-by: Himanshu Jha <himanshujha199640@...il.com>

Acked-by: Julia Lawall <julia.lawall@...6.fr>

> ---
>  scripts/coccinelle/api/alloc/kzalloc-simple.cocci | 371 +++++++++++++++++++++-
>  1 file changed, 367 insertions(+), 4 deletions(-)
>
> diff --git a/scripts/coccinelle/api/alloc/kzalloc-simple.cocci b/scripts/coccinelle/api/alloc/kzalloc-simple.cocci
> index 52c55e4..f94888d 100644
> --- a/scripts/coccinelle/api/alloc/kzalloc-simple.cocci
> +++ b/scripts/coccinelle/api/alloc/kzalloc-simple.cocci
> @@ -1,5 +1,5 @@
>  ///
> -/// Use kzalloc rather than kmalloc followed by memset with 0
> +/// Use zeroing allocator rather than allocator followed by memset with 0
>  ///
>  /// This considers some simple cases that are common and easy to validate
>  /// Note in particular that there are no ...s in the rule, so all of the
> @@ -8,6 +8,7 @@
>  // Confidence: High
>  // Copyright: (C) 2009-2010 Julia Lawall, Nicolas Palix, DIKU.  GPLv2.
>  // Copyright: (C) 2009-2010 Gilles Muller, INRIA/LiP6.  GPLv2.
> +// Cpoyright: (C) 2017 Himanshu Jha GPLv2.
>  // URL: http://coccinelle.lip6.fr/rules/kzalloc.html
>  // Options: --no-includes --include-headers
>  //
> @@ -28,11 +29,14 @@ virtual report
>  @depends on context@
>  type T, T2;
>  expression x;
> -expression E1,E2;
> +expression E1;
>  statement S;
>  @@
>
> -* x = (T)kmalloc(E1,E2);
> +* x = (T)\(kmalloc(E1, ...)\|vmalloc(E1)\|dma_alloc_coherent(...,E1,...)\|
> +  kmalloc_node(E1, ...)\|kmem_cache_alloc(...)\|kmem_alloc(E1, ...)\|
> +  devm_kmalloc(...,E1,...)\|kvmalloc(E1, ...)\|pci_alloc_consistent(...,E1,...)\|
> +  kvmalloc_node(E1,...)\);
>    if ((x==NULL) || ...) S
>  * memset((T2)x,0,E1);
>
> @@ -43,12 +47,101 @@ statement S;
>  @depends on patch@
>  type T, T2;
>  expression x;
> -expression E1,E2;
> +expression E1,E2,E3,E4;
>  statement S;
>  @@
>
> +(
> +- x = kmalloc(E1,E2);
> ++ x = kzalloc(E1,E2);
> +|
>  - x = (T)kmalloc(E1,E2);
> ++ x = (T)kzalloc(E1,E2);
> +|
> +- x = (T *)kmalloc(E1,E2);
>  + x = kzalloc(E1,E2);
> +|
> +- x = vmalloc(E1);
> ++ x = vzalloc(E1);
> +|
> +- x = (T)vmalloc(E1);
> ++ x = (T)vzalloc(E1);
> +|
> +- x = (T *)vmalloc(E1);
> ++ x = vzalloc(E1);
> +|
> +- x = dma_alloc_coherent(E2,E1,E3,E4);
> ++ x = dma_zalloc_coherent(E2,E1,E3,E4);
> +|
> +- x = (T)dma_alloc_coherent(E2,E1,E3,E4);
> ++ x = (T)dma_zalloc_coherent(E2,E1,E3,E4);
> +|
> +- x = (T *)dma_alloc_coherent(E2,E1,E3,E4);
> ++ x = dma_zalloc_coherent(E2,E1,E3,E4);
> +|
> +- x = kmalloc_node(E1,E2,E3);
> ++ x = kzalloc_node(E1,E2,E3);
> +|
> +- x = (T)kmalloc_node(E1,E2,E3);
> ++ x = (T)kzalloc_node(E1,E2,E3);
> +|
> +- x = (T *)kmalloc_node(E1,E2,E3);
> ++ x = kzalloc_node(E1,E2,E3);
> +|
> +- x = kmem_cache_alloc(E3,E4);
> ++ x = kmem_cache_zalloc(E3,E4);
> +|
> +- x = (T)kmem_cache_alloc(E3,E4);
> ++ x = (T)kmem_cache_zalloc(E3,E4);
> +|
> +- x = (T *)kmem_cache_alloc(E3,E4);
> ++ x = kmem_cache_zalloc(E3,E4);
> +|
> +- x = kmem_alloc(E1,E2);
> ++ x = kmem_zalloc(E1,E2);
> +|
> +- x = (T)kmem_alloc(E1,E2);
> ++ x = (T)kmem_zalloc(E1,E2);
> +|
> +- x = (T *)kmem_alloc(E1,E2);
> ++ x = kmem_zalloc(E1,E2);
> +|
> +- x = devm_kmalloc(E2,E1,E3);
> ++ x = devm_kzalloc(E2,E1,E3);
> +|
> +- x = (T)devm_kmalloc(E2,E1,E3);
> ++ x = (T)devm_kzalloc(E2,E1,E3);
> +|
> +- x = (T *)devm_kmalloc(E2,E1,E3);
> ++ x = devm_kzalloc(E2,E1,E3);
> +|
> +- x = kvmalloc(E1,E2);
> ++ x = kvzalloc(E1,E2);
> +|
> +- x = (T)kvmalloc(E1,E2);
> ++ x = (T)kvzalloc(E1,E2);
> +|
> +- x = (T *)kvmalloc(E1,E2);
> ++ x = kvzalloc(E1,E2);
> +|
> +- x = pci_alloc_consistent(E2,E1,E3);
> ++ x = pci_zalloc_consistent(E2,E1,E3);
> +|
> +- x = (T)pci_alloc_consistent(E2,E1,E3);
> ++ x = (T)pci_zalloc_consistent(E2,E1,E3);
> +|
> +- x = (T *)pci_alloc_consistent(E2,E1,E3);
> ++ x = pci_zalloc_consistent(E2,E1,E3);
> +|
> +- x = kvmalloc_node(E1,E2,E3);
> ++ x = kvzalloc_node(E1,E2,E3);
> +|
> +- x = (T)kvmalloc_node(E1,E2,E3);
> ++ x = (T)kvzalloc_node(E1,E2,E3);
> +|
> +- x = (T *)kvmalloc_node(E1,E2,E3);
> ++ x = kvzalloc_node(E1,E2,E3);
> +)
>    if ((x==NULL) || ...) S
>  - memset((T2)x,0,E1);
>
> @@ -84,3 +177,273 @@ x << r.x;
>
>  msg="WARNING: kzalloc should be used for %s, instead of kmalloc/memset" % (x)
>  coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r1 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)vmalloc@p(E1);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r1.p;
> +x << r1.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r1.p;
> +x << r1.x;
> +@@
> +
> +msg="WARNING: vzalloc should be used for %s, instead of vmalloc/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r2 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3,E4;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)dma_alloc_coherent@p(E2,E1,E3,E4);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r2.p;
> +x << r2.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r2.p;
> +x << r2.x;
> +@@
> +
> +msg="WARNING: dma_zalloc_coherent should be used for %s, instead of dma_alloc_coherent/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r3 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)kmalloc_node@p(E1,E2,E3);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r3.p;
> +x << r3.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r3.p;
> +x << r3.x;
> +@@
> +
> +msg="WARNING: kzalloc_node should be used for %s, instead of kmalloc_node/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r4 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)kmem_cache_alloc@p(E2,E3);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r4.p;
> +x << r4.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r4.p;
> +x << r4.x;
> +@@
> +
> +msg="WARNING: kmem_cache_zalloc should be used for %s, instead of kmem_cache_alloc/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r5 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)kmem_alloc@p(E1,E2);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r5.p;
> +x << r5.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r5.p;
> +x << r5.x;
> +@@
> +
> +msg="WARNING: kmem_zalloc should be used for %s, instead of kmem_alloc/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r6 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)devm_kmalloc@p(E2,E1,E3);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r6.p;
> +x << r6.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r6.p;
> +x << r6.x;
> +@@
> +
> +msg="WARNING: devm_kzalloc should be used for %s, instead of devm_kmalloc/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r7 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)kvmalloc@p(E1,E2);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r7.p;
> +x << r7.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r7.p;
> +x << r7.x;
> +@@
> +
> +msg="WARNING: kvzalloc should be used for %s, instead of kvmalloc/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> +//-----------------------------------------------------------------
> +@r8 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)pci_alloc_consistent@p(E2,E1,E3);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r8.p;
> +x << r8.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r8.p;
> +x << r8.x;
> +@@
> +
> +msg="WARNING: pci_zalloc_consistent should be used for %s, instead of pci_alloc_consistent/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +//-----------------------------------------------------------------
> +@r9 depends on org || report@
> +type T, T2;
> +expression x;
> +expression E1,E2,E3;
> +statement S;
> +position p;
> +@@
> +
> + x = (T)kvmalloc_node@p(E1,E2,E3);
> + if ((x==NULL) || ...) S
> + memset((T2)x,0,E1);
> +
> +@...ipt:python depends on org@
> +p << r9.p;
> +x << r9.x;
> +@@
> +
> +msg="%s" % (x)
> +msg_safe=msg.replace("[","@(").replace("]",")")
> +coccilib.org.print_todo(p[0], msg_safe)
> +
> +@...ipt:python depends on report@
> +p << r9.p;
> +x << r9.x;
> +@@
> +
> +msg="WARNING: kvzalloc_node should be used for %s, instead of kvmalloc_node/memset" % (x)
> +coccilib.report.print_report(p[0], msg)
> +
> --
> 2.7.4
>
>