Messages in this thread | | | Date | Tue, 15 Jan 2008 22:26:55 +0300 | From | "Anton Salikhmetov" <> | Subject | Re: [PATCH 1/2] Massive code cleanup of sys_msync() |
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2008/1/15, Randy Dunlap <randy.dunlap@oracle.com>: > On Tue, 15 Jan 2008 22:02:54 +0300 Anton Salikhmetov wrote: > > > 2008/1/15, Christoph Hellwig <hch@infradead.org>: > > > On Tue, Jan 15, 2008 at 07:02:44PM +0300, Anton Salikhmetov wrote: > > > > > @@ -33,71 +34,65 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) > > > > unsigned long end; > > > > struct mm_struct *mm = current->mm; > > > > struct vm_area_struct *vma; > > > > - int unmapped_error = 0; > > > > - int error = -EINVAL; > > > > + int error = 0, unmapped_error = 0; > > > > > > > > if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) > > > > - goto out; > > > > + return -EINVAL; > > > > if (start & ~PAGE_MASK) > > > > - goto out; > > > > + return -EINVAL; > > > > > > The goto out for a simple return style is used quite commonly in kernel > > > code to have a single return statement which makes code maintaince, e.g. > > > adding locks or allocations simpler. Not sure that getting rid of it > > > makes a lot of sense. > > > > Sorry, I can't agree. That's what is written in the CodingStyle document: > > > > The goto statement comes in handy when a function exits from multiple > > locations and some common work such as cleanup has to be done. > > CodingStyle does not try to cover Everything. Nor do we want it to. > > At any rate, there is a desire for functions to have a single point > of return, regardless of the amount of cleanup to be done, so I agree > with Christoph's comments.
Should I replace "return -EINVAL;" statement with the following?
{ error = -EINVAL; goto out; }
> > > > The second part of requirement does not hold true for the sys_msync() routine. > > > > > > > > > + file = vma->vm_file; > > > > + if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) { > > > > > > Given that file is assigned just above it would be more readable to test > > > it first. > > > > The second part of my solution changes this code, anyway. > > > > > > > > > + if (error) > > > > + return error; > > > > > > This should be an goto out, returns out of the middle of the function > > > make reading and maintaining the code not so nice. > > > > Sorry, I don't think so. No "common cleanup" is needed here. > > > --- > ~Randy >
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