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Re: [dm-devel] rdac.c patch not quite right.



On Thurs December 09, 2010 3:10 AM, Malahal Naineni Wrote:
> > -	} else if ((inq.PQ_PDT & 0x20) || (inq.PQ_PDT & 0x7f)) {
> > +	} else if (((inq.PQ_PDT & 0xE0) == 0x20) || (inq.PQ_PDT & 0x7f)) {
> >  		/* LUN not connected*/
> >  		ret = PATH_DOWN;
> >  		goto done;
> 
> I think this new patch has the same issue as the old one. In  other
> words, the second expression in the parenthesis is true if the first one
> is true. So you could as well just use the second expression. If you
> really want to use PQ as well as PDT with separate checks, you can do
> something like this:
> 
> 
> 	} else if (((inq.PQ_PDT & 0xE0) == 0x20) || (inq.PQ_PDT & 0x1F)) {
> 		/* LUN not connected or not a Direct Access device */
> 		ret = PATH_DOWN;
> 		goto done;
> 
> Please note the 7f to 1F change and the comment change to reflect the code
> check.

Malahal, Thanks for your review comment. First and second expression are two different comparisons. In First expression we are explicitly checking if PQ==001b. If the first expression is _FALSE_ then we check for second expression in which we compare if PQ==011b and PDT==11111b (i.e PQ_PDT = 01111111b=0x7F).

> 
Thanks,
Vijay


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