Messages in this thread | | | Date | Thu, 14 May 2009 19:57:46 +0200 | From | Vitaly Mayatskikh <> | Subject | Re: [PATCH 1/2] Introduce check_readable_bytes() |
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At Thu, 14 May 2009 13:40:09 -0400, Josef Bacik wrote:
> > + volatile char c; > > + int ret = 0; > > + long page_begin = (unsigned long)uaddr & PAGE_MASK; > > + long page_end = ((unsigned long)uaddr + size) & PAGE_MASK; > > + long ptr = page_begin; > > + > > Firstly page_begin/page_end/ptr should all be unsigned long. Secondly page_end > should be uaddr+size-1. > > > + if (unlikely(size == 0)) > > + goto out; > > + > > + while (!ret && ptr <= page_end) { > > + ret = __get_user(c, (const char __user*)ptr); > > + if (!ret) > > + ptr += PAGE_SIZE; > > + } > > + > > + if (likely(!ret)) > > + ret = size; > > + else > > + ret = (ptr == page_begin) ? > > + -EFAULT : (const char __user *)ptr - uaddr; > > This isn't quite right either, we do some pointer math, and return that and its > casted as an int? That seems like a bad idea in general. Thanks,
Did you like the approach in general?
-- wbr, Vitaly
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