From: zhong jiang <zhongjiang@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <vbabka@suse.cz>, <jhubbard@nvidia.com>, <linux-mm@kvack.org>,
<zhongjiang@huawei.com>
Subject: [PATCH] mm: Unsigned 'nr_pages' always larger than zero
Date: Thu, 17 Oct 2019 11:19:46 +0800 [thread overview]
Message-ID: <1571282386-65076-1-git-send-email-zhongjiang@huawei.com> (raw)
With the help of unsigned_lesser_than_zero.cocci. Unsigned 'nr_pages"'
compare with zero. And __get_user_pages_locked will return an long value.
The patch use a new local variable to store the return value of
__get_user_pages_locked(). Then use it to compare with zero.
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
mm/gup.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 8f236a3..1fe0ceb 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1443,6 +1443,7 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
bool drain_allow = true;
bool migrate_allow = true;
LIST_HEAD(cma_page_list);
+ long ret;
check_again:
for (i = 0; i < nr_pages;) {
@@ -1504,17 +1505,18 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
* again migrating any new CMA pages which we failed to isolate
* earlier.
*/
- nr_pages = __get_user_pages_locked(tsk, mm, start, nr_pages,
+ ret = __get_user_pages_locked(tsk, mm, start, nr_pages,
pages, vmas, NULL,
gup_flags);
- if ((nr_pages > 0) && migrate_allow) {
+ nr_pages = ret;
+ if ((ret > 0) && migrate_allow) {
drain_allow = true;
goto check_again;
}
}
- return nr_pages;
+ return ret;
}
#else
static long check_and_migrate_cma_pages(struct task_struct *tsk,
--
1.7.12.4
next reply other threads:[~2019-10-17 3:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-17 3:19 zhong jiang [this message]
2019-10-17 18:01 ` [PATCH] mm: Unsigned 'nr_pages' always larger than zero Ira Weiny
2019-10-18 2:01 ` zhong jiang
2019-10-17 20:42 ` John Hubbard
2019-10-18 2:15 ` zhong jiang
2019-10-18 14:00 ` zhong jiang
2019-10-18 16:07 ` Alexander Duyck
2019-10-21 15:11 ` zhong jiang
2019-10-21 12:57 ` Vlastimil Babka
2019-10-21 13:47 ` zhong jiang
-- strict thread matches above, loose matches on Subject: below --
2019-09-04 10:26 zhong jiang
2019-09-04 11:24 ` Vlastimil Babka
2019-09-04 18:25 ` Weiny, Ira
2019-09-04 18:39 ` Matthew Wilcox
2019-09-04 18:48 ` Andrew Morton
2019-09-04 20:20 ` Weiny, Ira
2019-09-04 20:40 ` Vlastimil Babka
2019-09-05 6:18 ` zhong jiang
2019-09-05 7:19 ` Vlastimil Babka
2019-09-05 6:19 ` John Hubbard
2019-10-16 9:07 ` zhong jiang
2019-10-17 0:49 ` Andrew Morton
2019-10-17 1:38 ` zhong jiang
2019-09-04 19:01 ` Andrew Morton
2019-09-04 20:44 ` Vlastimil Babka
2019-09-05 2:05 ` zhong jiang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1571282386-65076-1-git-send-email-zhongjiang@huawei.com \
--to=zhongjiang@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=jhubbard@nvidia.com \
--cc=linux-mm@kvack.org \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.