From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v3 05/16] util: MAX_FROM_BITS() should be unsigned
Date: Thu, 30 Nov 2023 13:02:11 +1100 [thread overview]
Message-ID: <20231130020222.4056647-6-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20231130020222.4056647-1-david@gibson.dropbear.id.au>
MAX_FROM_BITS() computes the maximum value representable in a number of
bits. The expression for that is an unsigned value, but we explicitly cast
it to a signed int. It looks like this is because one of the main users is
for FD_REF_MAX, which is used to bound fd values, typically stored as a
signed int.
The value MAX_FROM_BITS() is calculating is naturally non-negative, though,
so it makes more sense for it to be unsigned, and to move the case to the
definition of FD_REF_MAX.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
passt.h | 2 +-
util.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/passt.h b/passt.h
index 3f5dfb9..0fce637 100644
--- a/passt.h
+++ b/passt.h
@@ -87,7 +87,7 @@ union epoll_ref {
struct {
enum epoll_type type:8;
#define FD_REF_BITS 24
-#define FD_REF_MAX MAX_FROM_BITS(FD_REF_BITS)
+#define FD_REF_MAX ((int)MAX_FROM_BITS(FD_REF_BITS))
int32_t fd:FD_REF_BITS;
union {
union tcp_epoll_ref tcp;
diff --git a/util.h b/util.h
index 78a8fb2..b1106e8 100644
--- a/util.h
+++ b/util.h
@@ -42,7 +42,7 @@
#define ROUND_DOWN(x, y) ((x) & ~((y) - 1))
#define ROUND_UP(x, y) (((x) + (y) - 1) & ~((y) - 1))
-#define MAX_FROM_BITS(n) ((int)((1U << (n)) - 1))
+#define MAX_FROM_BITS(n) (((1U << (n)) - 1))
#define BIT(n) (1UL << (n))
#define BITMAP_BIT(n) (BIT((n) % (sizeof(long) * 8)))
--
@@ -42,7 +42,7 @@
#define ROUND_DOWN(x, y) ((x) & ~((y) - 1))
#define ROUND_UP(x, y) (((x) + (y) - 1) & ~((y) - 1))
-#define MAX_FROM_BITS(n) ((int)((1U << (n)) - 1))
+#define MAX_FROM_BITS(n) (((1U << (n)) - 1))
#define BIT(n) (1UL << (n))
#define BITMAP_BIT(n) (BIT((n) % (sizeof(long) * 8)))
--
2.43.0
next prev parent reply other threads:[~2023-11-30 2:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 2:02 [PATCH v3 00/16] Introduce unified flow table, first steps David Gibson
2023-11-30 2:02 ` [PATCH v3 01/16] treewide: Add messages to static_assert() calls David Gibson
2023-11-30 2:02 ` [PATCH v3 02/16] flow, tcp: Generalise connection types David Gibson
2023-11-30 2:02 ` [PATCH v3 03/16] flow, tcp: Move TCP connection table to unified flow table David Gibson
2023-11-30 2:02 ` [PATCH v3 04/16] flow, tcp: Consolidate flow pointer<->index helpers David Gibson
2023-11-30 2:02 ` David Gibson [this message]
2023-11-30 2:02 ` [PATCH v3 06/16] flow: Make unified version of flow table compaction David Gibson
2023-11-30 2:02 ` [PATCH v3 07/16] flow, tcp: Add logging helpers for connection related messages David Gibson
2023-11-30 2:02 ` [PATCH v3 08/16] flow: Introduce 'sidx' type to represent one side of one flow David Gibson
2023-12-02 4:35 ` Stefano Brivio
2023-11-30 2:02 ` [PATCH v3 09/16] tcp: Remove unneccessary bounds check in tcp_timer_handler() David Gibson
2023-11-30 2:02 ` [PATCH v3 10/16] flow,tcp: Generalise TCP epoll_ref to generic flows David Gibson
2023-11-30 2:02 ` [PATCH v3 11/16] tcp_splice: Use unsigned to represent side David Gibson
2023-11-30 2:02 ` [PATCH v3 12/16] flow,tcp: Use epoll_ref type including flow and side David Gibson
2023-11-30 2:02 ` [PATCH v3 13/16] test: Avoid hitting guestfish command length limits David Gibson
2023-11-30 2:02 ` [PATCH v3 14/16] pif: Add helpers to get the name of a pif David Gibson
2023-11-30 12:45 ` Stefano Brivio
2023-12-01 0:08 ` David Gibson
2023-11-30 2:02 ` [PATCH v3 15/16] tcp: "TCP" hash secret doesn't need to be TCP specific David Gibson
2023-11-30 2:02 ` [PATCH v3 16/16] tcp: Don't defer hash table removal David Gibson
2023-11-30 12:45 ` Stefano Brivio
2023-12-01 0:07 ` David Gibson
2023-12-02 4:34 ` Stefano Brivio
2023-12-04 0:43 ` David Gibson
2023-12-04 9:54 ` [PATCH v3 00/16] Introduce unified flow table, first steps Stefano Brivio
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