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DateSat, 29 Oct 2005 07:59:54 +0200
FromRichard Knutsson <>
SubjectRe: 2.6.14 assorted warnings
Jens Axboe wrote:

>On Fri, Oct 28 2005, Arnd Bergmann wrote:
> 
>
>>In the example, bvec_alloc_bs does not initialize &idx when nr is not
>>between 1 and BIO_MAX_PAGES, so gcc is telling the truth here.
>> 
>>
>
>Wrong. idx is always initialized if being used.
>
> 
>
Is the compiler really that smart as it searches back into the parent-function and try all the combinations? Otherwise, Arnd is correct.
And on an philosophical plane, can/should we put that responsibility onto the compiler? Is it not "easier" to make the functions take care
of its own duties (like the *nix-way) and make the bvec_alloc_bs initialize idx (even if it has to be an error-value)?

I'm thinking something like this. Seems alright?

/Richard

---
diff -Nurp a/fs/bio.c b/fs/bio.c
--- a/fs/bio.c	2005-10-29 06:30:49.000000000 +0200
+++ b/fs/bio.c	2005-10-29 06:33:00.000000000 +0200
@@ -90,6 +90,7 @@ static inline struct bio_vec *bvec_alloc
 		case  65 ... 128: *idx = 4; break;
 		case 129 ... BIO_MAX_PAGES: *idx = 5; break;
 		default:
+			*idx = -1;
 			return NULL;
 	}
 	/* 

-
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