| Message ID | 20250224141120.1240534-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] mm, cma: fix 32-bit warning | expand |
On 24 Feb 2025, at 9:07, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > clang warns about certain always-true conditions, like this one on 32-bit > builds: > > mm/cma.c:420:13: error: result of comparison of constant 4294967296 with expression of type 'phys_addr_t' (aka 'unsigned int') is always true [-Werror,-Wtautological-constant-out-of-range-compare] > 420 | if (start < SZ_4G) > | ~~~~~ ^ ~~~~~ > > Replace this one with an equivalent expression that does not cause a warning. > > Fixes: 4765deffa0f7 ("mm, cma: support multiple contiguous ranges, if requested") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > mm/cma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com> Best Regards, Yan, Zi
On 24.02.25 15:07, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > clang warns about certain always-true conditions, like this one on 32-bit > builds: > > mm/cma.c:420:13: error: result of comparison of constant 4294967296 with expression of type 'phys_addr_t' (aka 'unsigned int') is always true [-Werror,-Wtautological-constant-out-of-range-compare] > 420 | if (start < SZ_4G) > | ~~~~~ ^ ~~~~~ > Hm, so in this case the whole loop is unnecessary. In any case Acked-by: David Hildenbrand <david@redhat.com>
On Mon, Feb 24, 2025 at 6:11 AM Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > clang warns about certain always-true conditions, like this one on 32-bit > builds: > > mm/cma.c:420:13: error: result of comparison of constant 4294967296 with expression of type 'phys_addr_t' (aka 'unsigned int') is always true [-Werror,-Wtautological-constant-out-of-range-compare] > 420 | if (start < SZ_4G) > | ~~~~~ ^ ~~~~~ > > Replace this one with an equivalent expression that does not cause a warning. > > Fixes: 4765deffa0f7 ("mm, cma: support multiple contiguous ranges, if requested") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > mm/cma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/cma.c b/mm/cma.c > index 34a4df29af72..ef0206c0f16d 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -417,7 +417,7 @@ int __init cma_declare_contiguous_multi(phys_addr_t total_size, > * Create a list of ranges above 4G, largest range first. > */ > for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { > - if (start < SZ_4G) > + if (upper_32_bits(start) == 0) > continue; > > start = ALIGN(start, align); > -- > 2.39.5 > Thanks for fixing these nits in my patch series - which, btw, needs more reviews, if anyone's reading this - please :) Reviewed-by: Frank van der Linden <fvdl@google.com>
diff --git a/mm/cma.c b/mm/cma.c index 34a4df29af72..ef0206c0f16d 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -417,7 +417,7 @@ int __init cma_declare_contiguous_multi(phys_addr_t total_size, * Create a list of ranges above 4G, largest range first. */ for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { - if (start < SZ_4G) + if (upper_32_bits(start) == 0) continue; start = ALIGN(start, align);