From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Xi Wang , Xiangliang Yu , James Bottomley Subject: [ 031/221] SCSI: mvsas: fix undefined bit shift Date: Tue, 15 Jan 2013 10:49:18 -0800 Message-Id: <20130115185000.279975091@linuxfoundation.org> In-Reply-To: <20130115184958.025580322@linuxfoundation.org> References: <20130115184958.025580322@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xi Wang commit beecadea1b8d67f591b13f7099559f32f3fd601d upstream. The macro bit(n) is defined as ((u32)1 << n), and thus it doesn't work with n >= 32, such as in mvs_94xx_assign_reg_set(): if (i >= 32) { mvi->sata_reg_set |= bit(i); ... } The shift ((u32)1 << n) with n >= 32 also leads to undefined behavior. The result varies depending on the architecture. This patch changes bit(n) to do a 64-bit shift. It also simplifies mv_ffc64() using __ffs64(), since invoking ffz() with ~0 is undefined. Signed-off-by: Xi Wang Acked-by: Xiangliang Yu Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/mvsas/mv_94xx.h | 14 ++------------ drivers/scsi/mvsas/mv_sas.h | 2 +- 2 files changed, 3 insertions(+), 13 deletions(-) --- a/drivers/scsi/mvsas/mv_94xx.h +++ b/drivers/scsi/mvsas/mv_94xx.h @@ -258,21 +258,11 @@ enum sas_sata_phy_regs { #define SPI_ADDR_VLD_94XX (1U << 1) #define SPI_CTRL_SpiStart_94XX (1U << 0) -#define mv_ffc(x) ffz(x) - static inline int mv_ffc64(u64 v) { - int i; - i = mv_ffc((u32)v); - if (i >= 0) - return i; - i = mv_ffc((u32)(v>>32)); - - if (i != 0) - return 32 + i; - - return -1; + u64 x = ~v; + return x ? __ffs64(x) : -1; } #define r_reg_set_enable(i) \ --- a/drivers/scsi/mvsas/mv_sas.h +++ b/drivers/scsi/mvsas/mv_sas.h @@ -69,7 +69,7 @@ extern struct kmem_cache *mvs_task_list_ #define DEV_IS_EXPANDER(type) \ ((type == EDGE_DEV) || (type == FANOUT_DEV)) -#define bit(n) ((u32)1 << n) +#define bit(n) ((u64)1 << n) #define for_each_phy(__lseq_mask, __mc, __lseq) \ for ((__mc) = (__lseq_mask), (__lseq) = 0; \