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

Thadeu Lima de Souza Cascardo cascardo at holoscopio.com
Thu Aug 4 22:00:33 UTC 2011


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 at xenotime.net>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at holoscopio.com>
Cc: Stephen Rothwell <sfr at canb.auug.org.au>
Cc: Dan Magenheimer <dan.magenheimer at oracle.com>
Cc: Nitin Gupta <ngupta at vflare.org>
Cc: Greg KH <greg at kroah.com>
Cc: driverdevel <devel at driverdev.osuosl.org>
Cc: linux-next at vger.kernel.org
Cc: LKML <linux-kernel at vger.kernel.org>
---
 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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