SCSI: mvsas: fix undefined bit shift

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 <xi.wang@gmail.com>
Acked-by: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/mvsas/mv_94xx.h b/drivers/scsi/mvsas/mv_94xx.h
index 8835befe2c0e2ea33ea849eae9a81b16736a0a0c..d72aa6182bc5c9e9639ddf4a6f064184de9d0752 100644 (file)
--- a/drivers/scsi/mvsas/mv_94xx.h
+++ b/drivers/scsi/mvsas/mv_94xx.h
@@ -193,21 +193,11 @@ struct mvs_prd {
 #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) \

diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h
index 1367d8b9350de4580f32b64f9b4d8dc9520a2575..efc6965ca67fa794c1dd9c68f555b160a5a95087 100644 (file)
--- a/drivers/scsi/mvsas/mv_sas.h
+++ b/drivers/scsi/mvsas/mv_sas.h
@@ -73,7 +73,7 @@ extern struct kmem_cache *mvs_task_list_cache;
 #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;              \