[merged mm-nonmm-stable] acct-fix-accuracy-loss-for-input-value-of-encode_comp_t.patch removed from -mm tree

[merged mm-nonmm-stable] acct-fix-accuracy-loss-for-input-value-of-encode_comp_t.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: acct: fix accuracy loss for input value of encode_comp_t()
has been removed from the -mm tree.  Its filename was
     acct-fix-accuracy-loss-for-input-value-of-encode_comp_t.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Zheng Yejian <zhengyejian1@huawei.com>
Subject: acct: fix accuracy loss for input value of encode_comp_t()
Date: Sat, 15 May 2021 22:06:30 +0800

Patch series "Fix encode_comp_t()".

Type conversion in encode_comp_t() may look a bit problematic.


This patch (of 2):

See calculation of ac_{u,s}time in fill_ac():
  > ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime));
  > ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime));

Return value of nsec_to_AHZ() is always type of 'u64', but it is handled
as type of 'unsigned long' in encode_comp_t, and accuracy loss would
happen on 32-bit platform when 'unsigned long' value is 32-bit-width.

So 'u64' value of encode_comp_t() may look better.

Link: https://lkml.kernel.org/r/20210515140631.369106-1-zhengyejian1@huawei.com
Link: https://lkml.kernel.org/r/20210515140631.369106-2-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Randy Dunlap <rdunlap@infradead.org> # build-tested
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhang Jinhao <zhangjinhao2@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/acct.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/acct.c~acct-fix-accuracy-loss-for-input-value-of-encode_comp_t
+++ a/kernel/acct.c
@@ -320,7 +320,7 @@ void acct_exit_ns(struct pid_namespace *
 }
 
 /*
- *  encode an unsigned long into a comp_t
+ *  encode an u64 into a comp_t
  *
  *  This routine has been adopted from the encode_comp_t() function in
  *  the kern_acct.c file of the FreeBSD operating system. The encoding
@@ -331,7 +331,7 @@ void acct_exit_ns(struct pid_namespace *
 #define	EXPSIZE		3			/* Base 8 (3 bit) exponent. */
 #define	MAXFRACT	((1 << MANTSIZE) - 1)	/* Maximum fractional value. */
 
-static comp_t encode_comp_t(unsigned long value)
+static comp_t encode_comp_t(u64 value)
 {
 	int exp, rnd;
 
_

Patches currently in -mm which might be from zhengyejian1@huawei.com are