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authorPaul Burton <paul.burton@imgtec.com>2016-08-19 17:43:57 +0100
committerMartin K. Petersen <martin.petersen@oracle.com>2016-08-30 22:18:59 -0400
commitf8630bd7e2185d175f76b38b36609c45144e2d15 (patch)
tree5f80defef589138de79c27471ee9deeabf21c551 /drivers/scsi/sg.c
parentb9b6e80ad3b11778f1066d698a838bcc86efb6be (diff)
scsi: sg: Use mult_frac, drop MULDIV macro
The MULDIV macro is essentially a duplicate of the more standard mult_frac macro. Replace use of MULDIV with mult_frac & drop the duplication. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Acked-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/sg.c')
-rw-r--r--drivers/scsi/sg.c19
1 files changed, 4 insertions, 15 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index bb5ec2d6abdf..070332eb41f3 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -79,18 +79,7 @@ static void sg_proc_cleanup(void);
*/
#define SG_MAX_CDB_SIZE 252
-/*
- * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
- * Then when using 32 bit integers x * m may overflow during the calculation.
- * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
- * calculates the same, but prevents the overflow when both m and d
- * are "small" numbers (like HZ and USER_HZ).
- * Of course an overflow is inavoidable if the result of muldiv doesn't fit
- * in 32 bits.
- */
-#define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
-
-#define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
+#define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
int sg_big_buff = SG_DEF_RESERVED_SIZE;
/* N.B. This variable is readable and writeable via
@@ -884,11 +873,11 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return result;
if (val < 0)
return -EIO;
- if (val >= MULDIV((s64)INT_MAX, USER_HZ, HZ))
- val = min_t(s64, MULDIV((s64)INT_MAX, USER_HZ, HZ),
+ if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
+ val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
INT_MAX);
sfp->timeout_user = val;
- sfp->timeout = MULDIV (val, HZ, USER_HZ);
+ sfp->timeout = mult_frac(val, HZ, USER_HZ);
return 0;
case SG_GET_TIMEOUT: /* N.B. User receives timeout as return value */

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