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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-28 23:03:48 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-28 23:41:14 +0300 |
| commit | 4477b39c32fdc03363affef4b11d48391e6dc9ff (patch) | |
| tree | 29fdc4e2d7b47dd23deb73f0660f358669d5c037 /arch/x86/mm | |
| parent | 7e2d0ba732ad649c557b49b0a3ef69d54df256d0 (diff) | |
| download | linux-4477b39c32fdc03363affef4b11d48391e6dc9ff.tar.xz | |
minmax: add a few more MIN_T/MAX_T users
Commit 3a7e02c040b1 ("minmax: avoid overly complicated constant
expressions in VM code") added the simpler MIN_T/MAX_T macros in order
to avoid some excessive expansion from the rather complicated regular
min/max macros.
The complexity of those macros stems from two issues:
(a) trying to use them in situations that require a C constant
expression (in static initializers and for array sizes)
(b) the type sanity checking
and MIN_T/MAX_T avoids both of these issues.
Now, in the whole (long) discussion about all this, it was pointed out
that the whole type sanity checking is entirely unnecessary for
min_t/max_t which get a fixed type that the comparison is done in.
But that still leaves min_t/max_t unnecessarily complicated due to
worries about the C constant expression case.
However, it turns out that there really aren't very many cases that use
min_t/max_t for this, and we can just force-convert those.
This does exactly that.
Which in turn will then allow for much simpler implementations of
min_t()/max_t(). All the usual "macros in all upper case will evaluate
the arguments multiple times" rules apply.
We should do all the same things for the regular min/max() vs MIN/MAX()
cases, but that has the added complexity of various drivers defining
their own local versions of MIN/MAX, so that needs another level of
fixes first.
Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.com/
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pgtable.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 93e54ba91fbf..f5931499c2d6 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -110,7 +110,7 @@ static inline void pgd_list_del(pgd_t *pgd) #define UNSHARED_PTRS_PER_PGD \ (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD) #define MAX_UNSHARED_PTRS_PER_PGD \ - max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD) + MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD) static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm) |