[PATCH] zcache: Use div_u64 for 64-bit division

From: Thadeu Lima de Souza Cascardo
Date: Thu Aug 04 2011 - 18:01:04 EST


xv_get_total_size_bytes returns a u64 value and it's used in a division.
This causes build failures in 32-bit architectures, as reported by Randy
Dunlap.

Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: driverdevel <devel@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-next@xxxxxxxxxxxxxxx
Cc: LKML <linux-kernel@xxxxxxxxxxxxxxx>
---
drivers/staging/zcache/zcache-main.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index 66469ac..2c41c44 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -28,6 +28,7 @@
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/atomic.h>
+#include <linux/math64.h>
#include "tmem.h"

#include "../zram/xvmalloc.h" /* if built in drivers/staging */
@@ -1162,6 +1163,7 @@ static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
uint16_t client_id = get_client_id_from_client(cli);
unsigned long zv_mean_zsize;
unsigned long curr_pers_pampd_count;
+ u64 total_zsize;

if (eph) {
ret = zcache_compress(page, &cdata, &clen);
@@ -1194,8 +1196,9 @@ static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
}
/* reject if mean compression is too poor */
if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
- zv_mean_zsize = xv_get_total_size_bytes(cli->xvpool) /
- curr_pers_pampd_count;
+ total_zsize = xv_get_total_size_bytes(cli->xvpool);
+ zv_mean_zsize = div_u64(total_zsize,
+ curr_pers_pampd_count);
if (zv_mean_zsize > zv_max_mean_zsize) {
zcache_mean_compress_poor++;
goto out;
--
1.7.5.4

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