[PATCH v1 01/11] x86/mm/pat: factor out setting cachemode into pgprot_set_cachemode()

David Hildenbrand
2025-04-25T08:17:29Z

Let's factor it out to make the code easier to grasp.

Use it also in pgprot_writecombine()/pgprot_writethrough() where
clearing the old cachemode might not be required, but given that we are
already doing a function call, no need to care about this
micro-optimization.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/x86/mm/pat/memtype.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index 72d8cbc611583..edec5859651d6 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -800,6 +800,12 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
}
#endif /* CONFIG_STRICT_DEVMEM */

+static inline void pgprot_set_cachemode(pgprot_t *prot, enum page_cache_mode pcm)
+{
+ *prot = __pgprot((pgprot_val(*prot) & ~_PAGE_CACHE_MASK) |
+ cachemode2protval(pcm));
+}
+
int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t *vma_prot)
{
@@ -811,8 +817,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
if (file->f_flags & O_DSYNC)
pcm = _PAGE_CACHE_MODE_UC_MINUS;

- *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
- cachemode2protval(pcm));
+ pgprot_set_cachemode(vma_prot, pcm);
return 1;
}

@@ -880,9 +885,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
(unsigned long long)paddr,
(unsigned long long)(paddr + size - 1),
cattr_name(pcm));
- *vma_prot = __pgprot((pgprot_val(*vma_prot) &
- (~_PAGE_CACHE_MASK)) |
- cachemode2protval(pcm));
+ pgprot_set_cachemode(vma_prot, pcm);
}
return 0;
}
@@ -907,9 +910,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
* We allow returning different type than the one requested in
* non strict case.
*/
- *vma_prot = __pgprot((pgprot_val(*vma_prot) &
- (~_PAGE_CACHE_MASK)) |
- cachemode2protval(pcm));
+ pgprot_set_cachemode(vma_prot, pcm);
}

if (memtype_kernel_map_sync(paddr, size, pcm) < 0) {
@@ -1060,9 +1061,7 @@ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
return -EINVAL;
}

- *prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) |
- cachemode2protval(pcm));
-
+ pgprot_set_cachemode(prot, pcm);
return 0;
}

@@ -1073,10 +1072,8 @@ void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, pfn_t pfn)
if (!pat_enabled())
return;

- /* Set prot based on lookup */
pcm = lookup_memtype(pfn_t_to_phys(pfn));
- *prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) |
- cachemode2protval(pcm));
+ pgprot_set_cachemode(prot, pcm);
}

/*
@@ -1115,15 +1112,15 @@ void untrack_pfn_clear(struct vm_area_struct *vma)

pgprot_t pgprot_writecombine(pgprot_t prot)
{
- return __pgprot(pgprot_val(prot) |
- cachemode2protval(_PAGE_CACHE_MODE_WC));
+ pgprot_set_cachemode(&prot, _PAGE_CACHE_MODE_WC);
+ return prot;
}
EXPORT_SYMBOL_GPL(pgprot_writecombine);

pgprot_t pgprot_writethrough(pgprot_t prot)
{
- return __pgprot(pgprot_val(prot) |
- cachemode2protval(_PAGE_CACHE_MODE_WT));
+ pgprot_set_cachemode(&prot, _PAGE_CACHE_MODE_WT);
+ return prot;
}
EXPORT_SYMBOL_GPL(pgprot_writethrough);

--
2.49.0