linux-kernel - Re: [Cocci] Re: status of constification

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Message-ID: <4DEBF96D.3030209@gmail.com>
Date:	Sun, 05 Jun 2011 23:47:25 +0200
From:	Emese Revfy <re.emese@...il.com>
To:	Julia Lawall <julia@...u.dk>
CC:	Kees Cook <kees.cook@...onical.com>, linux-kernel@...r.kernel.org,
	cocci@...u.dk
Subject: Re: [Cocci] Re: status of constification

> Could I see the semantic patch?  The clean up issue sounds interesting.
> Perhaps there is a way around it.

Hi,
I no longer use Coccinelle to generate constification patch, but only to find
candidate structures for constification. This is because I ran into several issues
some of which I will try describe now from memory (unfortunately I don't have
those Cocci scripts anymore):

1. Sometimes (always?) cocci removed NULL initialization while emitting the constified patch:

linux-2.6.39-rc7/arch/frv/mb93090-mb00/pci-vdk.c
@@ -356,7 +356,7 @@ void __init pcibios_fixup_bus(struct pci
  
  int __init pcibios_init(void)
  {
-       struct pci_ops *dir = NULL;
+       const struct pci_ops *dir;
  
         if (!mb93090_mb00_detected)
                 return -ENXIO;

2. Sometimes (always?) cocci joined structure field lines into one line while constifying  them:

linux-2.6.39-rc7/arch/x86/include/asm/x86_init.h
@@ -119,14 +119,7 @@ struct x86_init_pci {
   *
   */
  struct x86_init_ops {
-       struct x86_init_resources       resources;
-       struct x86_init_mpparse         mpparse;
-       struct x86_init_irqs            irqs;
-       struct x86_init_oem             oem;
-       struct x86_init_paging          paging;
-       struct x86_init_timers          timers;
-       struct x86_init_iommu           iommu;
-       struct x86_init_pci             pci;
+       const struct x86_init_resources resources;const struct x86_init_mpparse mpparse;const struct x86_init_irqs irqs;const struct x86_init_oem oem;const struct x86_init_paging paging;const struct x86_init_timers timers;const struct x86_init_iommu iommu;const struct x86_init_pci pci;
  };

  /**

3. Sometimes cocci removed comment lines while joining others, maybe related
    to the previous issue:
  
linux-2.6.39-rc7/drivers/net/wireless/ath/ath9k/hw.h
@@ -753,9 +753,7 @@ struct ath_hw {
         } enable_32kHz_clock;

         /* Private to hardware code */
-       struct ath_hw_private_ops private_ops;
-       /* Accessed by the lower level driver */
-       struct ath_hw_ops ops;
+       const struct ath_hw_private_ops private_ops;const struct ath_hw_ops ops;

         /* Used to program the radio on non single-chip devices */
         u32 *analogBank0Data;

4. My constification patch generator cocci script didn't find all structures that it should have, I don't know whether it was a bug in my script or in cocci but in the end I just gave it up.

--
Emese
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