[Focal:*-5.15] UBUNTU: SAUCE: Work-around compile bug in gcc-9.4

[Stefan Bader]

Upstream stable v5.15.195 contained a rather big set of patches
reworking the min/max and clamp macros:

  - minmax: add in_range() macro
  - minmax: Introduce {min,max}_array()
  - minmax: deduplicate __unconst_integer_typeof()
  - minmax: fix indentation of __cmp_once() and __clamp_once()
  - minmax: avoid overly complicated constant expressions in VM code
  - minmax: add a few more MIN_T/MAX_T users
  - minmax: simplify and clarify min_t()/max_t() implementation
  - minmax: make generic MIN() and MAX() macros available everywhere
  - minmax: don't use max() in situations that want a C constant expression
  - minmax: simplify min()/max()/clamp() implementation
  - minmax: improve macro expansion and type checking
  - minmax: fix up min3() and max3() too
  - minmax.h: add whitespace around operators and after commas
  - minmax.h: update some comments
  - minmax.h: reduce the #define expansion of min(), max() and clamp()
  - minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
  - minmax.h: move all the clamp() definitions after the min/max() ones
  - minmax.h: simplify the variants of clamp()
  - minmax.h: remove some #defines that are only expanded once

This works without problems when compiled with gcc-11 (Jammy) but
unexpectedly breaks when compiling with gcc-9 (Focal). Somehow the
compiler considers (u32) always bigger than ((unsigned long)/unsigned
int)). There might be other places but for the generic build this
happens only in fs/nfs/nfs4stat.c. To work around this we add a cast to
unsigned long.

Ignore: yes
Fixes: Jammy update: v5.15.195 upstream stable release (2133909)
Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
---

I know this is not the standard format and procedure but this is needed
to get a 5.15 backport for the 2026.01.12 cycle compiled in focal...

 fs/nfsd/nfs4state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index df982830efc2..d8e014535ae1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1823,7 +1823,7 @@ static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn
 	scale_factor = max_t(unsigned int, 8, nn->nfsd_serv->sv_nrthreads);
 
 	avail = clamp_t(unsigned long, avail, slotsize,
-			total_avail/scale_factor);
+			((unsigned long) total_avail/scale_factor));
 	num = min_t(int, num, avail / slotsize);
 	num = max_t(int, num, 1);
 	nfsd_drc_mem_used += num * slotsize;
-- 
2.43.0