[PATCH] bnx2fc: shift wrapping bug in bnx2fc_process_unsol_compl()

[PATCH] bnx2fc: shift wrapping bug in bnx2fc_process_unsol_compl()

[Christophe JAILLET]

BNX2FC_NUM_ERR_BITS is 63. err_warn_bit_map is a u64. So, to make sure that
no shift wrapping will occur, we need need additionnal casting.

The same test is already done a few lines above and '(u64)1' is already
used there. So just do the same here.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
I guess that this could also be written with a '1ULL << i' which would be
cleaner and less verbose IMHO, but apparently this driver does not use
such things yet. So keep the current style with casting.
---
 drivers/scsi/bnx2fc/bnx2fc_hwi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_hwi.c b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
index 5ff9f89c17c7..a9dccb3b49cc 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_hwi.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
@@ -829,7 +829,7 @@ static void bnx2fc_process_unsol_compl(struct bnx2fc_rport *tgt, u16 wqe)
 			((u64)err_entry->data.err_warn_bitmap_hi << 32) |
 			(u64)err_entry->data.err_warn_bitmap_lo;
 		for (i = 0; i < BNX2FC_NUM_ERR_BITS; i++) {
-			if (err_warn_bit_map & (u64) (1 << i)) {
+			if (err_warn_bit_map & (u64)((u64)1 << i)) {
 				err_warn = i;
 				break;
 			}
-- 
2.9.3

Re: [PATCH] bnx2fc: shift wrapping bug in bnx2fc_process_unsol_compl()

[Dan Carpenter]

On Sat, Nov 26, 2016 at 07:36:29PM +0100, Christophe JAILLET wrote:
> BNX2FC_NUM_ERR_BITS is 63. err_warn_bit_map is a u64. So, to make sure that
> no shift wrapping will occur, we need need additionnal casting.
> 
> The same test is already done a few lines above and '(u64)1' is already
> used there. So just do the same here.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> I guess that this could also be written with a '1ULL << i' which would be
> cleaner and less verbose IMHO, but apparently this driver does not use
> such things yet. So keep the current style with casting.

Ugh...  No.  This is not code to emulate.  Use 1ULL << i.  Even if we
did the cast, you would only need one:

			if (err_warn_bit_map & ((u64)1 << i)) {


regards,
dan carpenter

Re: [PATCH] bnx2fc: shift wrapping bug in bnx2fc_process_unsol_compl()

[Laurence Oberman]

----- Original Message -----
> From: "Christophe JAILLET" <christophe.jaillet@wanadoo.fr>
> To: QLogic-Storage-Upstream@qlogic.com, jejb@linux.vnet.ibm.com, "martin petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, "Christophe JAILLET"
> <christophe.jaillet@wanadoo.fr>
> Sent: Saturday, November 26, 2016 1:36:29 PM
> Subject: [PATCH] bnx2fc: shift wrapping bug in bnx2fc_process_unsol_compl()
> 
> BNX2FC_NUM_ERR_BITS is 63. err_warn_bit_map is a u64. So, to make sure that
> no shift wrapping will occur, we need need additionnal casting.
> 
> The same test is already done a few lines above and '(u64)1' is already
> used there. So just do the same here.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> I guess that this could also be written with a '1ULL << i' which would be
> cleaner and less verbose IMHO, but apparently this driver does not use
> such things yet. So keep the current style with casting.
> ---
>  drivers/scsi/bnx2fc/bnx2fc_hwi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> index 5ff9f89c17c7..a9dccb3b49cc 100644
> --- a/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> +++ b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> @@ -829,7 +829,7 @@ static void bnx2fc_process_unsol_compl(struct
> bnx2fc_rport *tgt, u16 wqe)
>  			((u64)err_entry->data.err_warn_bitmap_hi << 32) |
>  			(u64)err_entry->data.err_warn_bitmap_lo;
>  		for (i = 0; i < BNX2FC_NUM_ERR_BITS; i++) {
> -			if (err_warn_bit_map & (u64) (1 << i)) {
> +			if (err_warn_bit_map & (u64)((u64)1 << i)) {
>  				err_warn = i;
>  				break;
>  			}
> --
> 2.9.3
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Looks fine to me.
Reviewed-by: Laurence Oberman <loberman@redhat.com>