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| author | NeilBrown <neil@brown.name> | 2025-11-14 16:19:22 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-12-07 06:18:53 +0900 |
| commit | 0722d804f7ad664424480cbb5d08292fd8ca08fb (patch) | |
| tree | 733cfe3b2c72a3f02eea001385d784166f7e7715 | |
| parent | 5106da73b01668a1aa5d0f352b95d2b832b5caa7 (diff) | |
| download | linux-0722d804f7ad664424480cbb5d08292fd8ca08fb.tar.gz linux-0722d804f7ad664424480cbb5d08292fd8ca08fb.tar.bz2 linux-0722d804f7ad664424480cbb5d08292fd8ca08fb.zip | |
nfsd: Replace clamp_t in nfsd4_get_drc_mem()
A recent change to clamp_t() in 6.1.y caused fs/nfsd/nfs4state.c to fail
to compile with gcc-9. The code in nfsd4_get_drc_mem() was written with
the assumption that when "max < min",
clamp(val, min, max)
would return max. This assumption is not documented as an API promise
and the change caused a compile failure if it could be statically
determined that "max < min".
The relevant code was no longer present upstream when commit 1519fbc8832b
("minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()")
landed there, so there is no upstream change to nfsd4_get_drc_mem() to
backport.
There is no clear case that the existing code in nfsd4_get_drc_mem()
is functioning incorrectly. The goal of this patch is to permit the clean
application of commit 1519fbc8832b ("minmax.h: use BUILD_BUG_ON_MSG() for
the lo < hi test in clamp()"), and any commits that depend on it, to LTS
kernels without affecting the ability to compile those kernels. This is
done by open-coding the __clamp() macro sans the built-in type checking.
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220745#c0
Signed-off-by: NeilBrown <neil@brown.name>
Stable-dep-of: 1519fbc8832b ("minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed_by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/nfsd/nfs4state.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index e6d0c3b1169a..57f1f6aa19c9 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1820,8 +1820,10 @@ 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); + if (avail > total_avail / scale_factor) + avail = total_avail / scale_factor; + else if (avail < slotsize) + avail = slotsize; num = min_t(int, num, avail / slotsize); num = max_t(int, num, 1); nfsd_drc_mem_used += num * slotsize; |