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SubjectRe: [PATCH 6/10] hpsa: use safer test on the result of find_first_zero_bit
On Wed, Jun 04, 2014 at 11:07:56AM +0200, Julia Lawall wrote:
> From: Julia Lawall <Julia.Lawall@lip6.fr>
>
> Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may
> return a larger number than the maximum position argument if that position
> is not a multiple of BITS_PER_LONG.
>
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> expression e1,e2,e3;
> statement S1,S2;
> @@
>
> e1 = find_first_zero_bit(e2,e3)
> ...
> if (e1
> - ==
> + >=
> e3)
> S1 else S2
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>
> ---
> drivers/scsi/hpsa.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff -u -p a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -4703,7 +4703,7 @@ static struct CommandList *cmd_alloc(str
> spin_lock_irqsave(&h->lock, flags);
> do {
> i = find_first_zero_bit(h->cmd_pool_bits, h->nr_cmds);
> - if (i == h->nr_cmds) {
> + if (i >= h->nr_cmds) {
> spin_unlock_irqrestore(&h->lock, flags);
> return NULL;
> }

Thanks, Ack.

You can add

Reviewed-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>

to this patch if you want.

You might also consider adding "Cc: stable@vger.kernel.org" to the sign-off area.

-- steve



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