From: david.laight.linux@gmail.com
To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Jakub Sitnicki <jakub@cloudflare.com>,
John Fastabend <john.fastabend@gmail.com>,
Paolo Abeni <pabeni@redhat.com>,
David Laight <david.laight.linux@gmail.com>
Subject: [PATCH 41/44] net/core: Change loop conditions so min() can be used
Date: Wed, 19 Nov 2025 22:41:37 +0000 [thread overview]
Message-ID: <20251119224140.8616-42-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20251119224140.8616-1-david.laight.linux@gmail.com>
From: David Laight <david.laight.linux@gmail.com>
Loops like:
int copied = ...;
...
while (copied) {
use = min_t(type, copied, PAGE_SIZE - offset);
...
copied -= 0;
}
can be converted to a plain min() if the comparison is changed to:
while (copied > 0) {
This removes any chance of high bits being discded by min_t().
(In the case above PAGE_SIZE is 64bits so the 'int' cast is safe,
but there are plenty of cases where the check shows up bugs.)
Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
net/core/datagram.c | 6 +++---
net/core/skmsg.c | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index c285c6465923..555f38b89729 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -664,8 +664,8 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
head = compound_head(pages[n]);
order = compound_order(head);
- for (refs = 0; copied != 0; start = 0) {
- int size = min_t(int, copied, PAGE_SIZE - start);
+ for (refs = 0; copied > 0; start = 0) {
+ int size = min(copied, PAGE_SIZE - start);
if (pages[n] - head > (1UL << order) - 1) {
head = compound_head(pages[n]);
@@ -783,7 +783,7 @@ EXPORT_SYMBOL(__zerocopy_sg_from_iter);
*/
int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
{
- int copy = min_t(int, skb_headlen(skb), iov_iter_count(from));
+ int copy = min(skb_headlen(skb), iov_iter_count(from));
/* copy up to skb headlen */
if (skb_copy_datagram_from_iter(skb, 0, from, copy))
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 2ac7731e1e0a..b58e319f4e2e 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -335,8 +335,8 @@ int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
bytes -= copied;
msg->sg.size += copied;
- while (copied) {
- use = min_t(int, copied, PAGE_SIZE - offset);
+ while (copied > 0) {
+ use = min(copied, PAGE_SIZE - offset);
sg_set_page(&msg->sg.data[msg->sg.end],
pages[i], use, offset);
sg_unmark_end(&msg->sg.data[msg->sg.end]);
--
2.39.5
next prev parent reply other threads:[~2025-11-19 22:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-19 22:40 [PATCH 00/44] Change a lot of min_t() that might mask high bits david.laight.linux
2025-11-19 22:41 ` [PATCH 07/44] net/core/flow_dissector: Fix cap of __skb_flow_dissect() return value david.laight.linux
2025-11-19 22:41 ` [PATCH 08/44] net: ethtool: Use min3() instead of nested min_t(u16,...) david.laight.linux
2025-11-19 22:41 ` [PATCH 09/44] ipv6: __ip6_append_data() don't abuse max_t() casts david.laight.linux
2025-11-20 0:32 ` bot+bpf-ci
2025-11-20 11:16 ` David Laight
2025-11-20 13:50 ` Chris Mason
2025-11-19 22:41 ` [PATCH 21/44] drivers/net/ethernet/realtek: use min() instead of min_t() david.laight.linux
2025-11-19 22:41 ` [PATCH 40/44] net: Don't pass bitfields to max_t() david.laight.linux
2025-11-19 22:41 ` david.laight.linux [this message]
2025-11-19 22:41 ` [PATCH 42/44] net: use min() instead of min_t() david.laight.linux
2025-11-19 22:41 ` [PATCH 43/44] net/netlink: Use umin() to avoid min_t(int, ...) discarding high bits david.laight.linux
2025-11-19 22:41 ` [PATCH 44/44] net/mptcp: Change some dubious min_t(int, ...) to min() david.laight.linux
2025-12-18 17:33 ` Matthieu Baerts
2025-12-18 20:15 ` David Laight
2025-12-19 10:48 ` Matthieu Baerts
2025-11-20 1:47 ` [PATCH 00/44] Change a lot of min_t() that might mask high bits Jakub Kicinski
2025-11-20 9:38 ` Lorenzo Stoakes
2025-11-20 14:52 ` (subset) " Jens Axboe
2025-11-24 9:49 ` Herbert Xu
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