[U-Boot] [RFC PATCH] ext4: Fix comparision of unsigned expression with < 0

[Tom Rini]

On Wed, Apr 26, 2017 at 08:56:49AM +0530, Lokesh Vutla wrote:
> 
> 
> On Tuesday 25 April 2017 11:34 PM, Tom Rini wrote:
> > On Tue, Apr 25, 2017 at 10:22:27AM +0530, Lokesh Vutla wrote:
> >> In file ext4fs.c funtion ext4fs_read_file() compares an
> >> unsigned expression with < 0 like below
> >>
> >> 	lbaint_t blknr;
> >> 	blknr = read_allocated_block(&(node->inode), i);
> >> 	if (blknr < 0)
> >> 		return -1;
> >>
> >> blknr is of type ulong/uint64_t. read_allocated_block() returns
> >> long int. So comparing blknr with < 0 will always be false. Instead
> >> declare blknr as long int.
> >>
> >> Reported-by: Sunita Nadampalli <sunitan at ti.com>
> >> Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
> >> ---
> >>  fs/ext4/ext4fs.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
> >> index 7187dcfb05..081509dbb4 100644
> >> --- a/fs/ext4/ext4fs.c
> >> +++ b/fs/ext4/ext4fs.c
> >> @@ -71,7 +71,7 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
> >>  	blockcnt = lldiv(((len + pos) + blocksize - 1), blocksize);
> >>  
> >>  	for (i = lldiv(pos, blocksize); i < blockcnt; i++) {
> >> -		lbaint_t blknr;
> >> +		long int blknr;
> >>  		int blockoff = pos - (blocksize * i);
> >>  		int blockend = blocksize;
> >>  		int skipfirst = 0;
> > 
> > My only question is, did you catch that by inspection, clang, or a newer
> 
> This is reported by Sunita and not sure how she caught it.

OK.  Because if she's got clang used on a TI platform and linking and
booting, I'd very much like to hear what else is required, or if
nothing, what version of the tools she's using, so I can put that into
my CI loop.  I didn't have luck when I tried last, but it was a while
ago.

> > than gcc-6.3 warning?  Also, fs/ext4/dev.c:63 is a similar problem, if
> > you'd like to non-RFC a v2.  Thanks!
> 
> In this case do you want me to drop the check or change lbaint_t to long
> int and update the argument type cast where ever ext4fs_devread() is called?

Just drop it I think, thanks.

-- 
Tom
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