BUILD: fd: fix a build warning on the DWCAS
Ilya reported in issue #1816 a build warning on armhf (promoted to error
here since -Werror):
src/fd.c: In function fd_rm_from_fd_list:
src/fd.c:209:87: error: passing argument 3 of __ha_cas_dw discards volatile qualifier from pointer target type [-Werror=discarded-array-qualifiers]
209 | unlikely(!_HA_ATOMIC_DWCAS(((long *)&fdtab[fd].update), (uint32_t *)&cur_list.u32, &next_list.u32))
| ^~~~~~~~~~~~~~
This happens only on such an architecture because the DWCAS requires the
pointer not the value, and gcc seems to be needlessly picky about reading
a const from a volatile! This may safely be backported to older versions.
diff --git a/src/fd.c b/src/fd.c
index 65036c7..eb386a8 100644
--- a/src/fd.c
+++ b/src/fd.c
@@ -206,7 +206,7 @@
#ifdef HA_CAS_IS_8B
unlikely(!_HA_ATOMIC_CAS(((uint64_t *)&fdtab[fd].update), (uint64_t *)&cur_list.u64, next_list.u64))
#else
- unlikely(!_HA_ATOMIC_DWCAS(((long *)&fdtab[fd].update), (uint32_t *)&cur_list.u32, &next_list.u32))
+ unlikely(!_HA_ATOMIC_DWCAS(((long *)&fdtab[fd].update), (uint32_t *)&cur_list.u32, (const uint32_t *)&next_list.u32))
#endif
);
next = cur_list.ent.next;