diff mbox series

[v4,05/36] mm: Add default definition of set_ptes()

Message ID 20230315051444.3229621-6-willy@infradead.org
State New
Headers
Series New page table range API |

Commit Message

Matthew Wilcox March 15, 2023, 5:14 a.m. UTC 
  Most architectures can just define set_pte() and PFN_PTE_SHIFT to
use this definition.  It's also a handy spot to document the guarantees
provided by the MM.

Suggested-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/pgtable.h | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

Comments

Mike Rapoport March 15, 2023, 9:34 a.m. UTC | #1 
On Wed, Mar 15, 2023 at 05:14:13AM +0000, Matthew Wilcox (Oracle) wrote:
> Most architectures can just define set_pte() and PFN_PTE_SHIFT to
> use this definition.  It's also a handy spot to document the guarantees
> provided by the MM.
> 
> Suggested-by: Mike Rapoport (IBM) <rppt@kernel.org>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  include/linux/pgtable.h | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index c5a51481bbb9..a755fe94b4b4 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -172,6 +172,43 @@ static inline int pmd_young(pmd_t pmd)
>  }
>  #endif
>  
> +#ifndef set_ptes
> +#ifdef PFN_PTE_SHIFT
> +/**
> + * set_ptes - Map consecutive pages to a contiguous range of addresses.
> + * @mm: Address space to map the pages into.
> + * @addr: Address to map the first page at.
> + * @ptep: Page table pointer for the first entry.
> + * @pte: Page table entry for the first page.
> + * @nr: Number of pages to map.
> + *
> + * May be overridden by the architecture, or the architecture can define
> + * set_pte() and PFN_PTE_SHIFT.
> + *
> + * Context: The caller holds the page table lock.  The pages all belong
> + * to the same folio.  The PTEs are all in the same PMD.
> + */
> +static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> +		pte_t *ptep, pte_t pte, unsigned int nr)
> +{
> +	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
> +
> +	for (;;) {
> +		set_pte(ptep, pte);
> +		if (--nr == 0)
> +			break;
> +		ptep++;
> +		pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> +	}
> +}
> +#ifndef set_pte_at
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif
> +#endif
> +#else
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif
> +
>  #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
>  extern int ptep_set_access_flags(struct vm_area_struct *vma,
>  				 unsigned long address, pte_t *ptep,
> -- 
> 2.39.2
>
Anshuman Khandual May 25, 2023, 3:01 a.m. UTC | #2 
On 3/15/23 10:44, Matthew Wilcox (Oracle) wrote:
> Most architectures can just define set_pte() and PFN_PTE_SHIFT to
> use this definition.  It's also a handy spot to document the guarantees
> provided by the MM.
> 
> Suggested-by: Mike Rapoport (IBM) <rppt@kernel.org>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  include/linux/pgtable.h | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index c5a51481bbb9..a755fe94b4b4 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -172,6 +172,43 @@ static inline int pmd_young(pmd_t pmd)
>  }
>  #endif
>  
> +#ifndef set_ptes
> +#ifdef PFN_PTE_SHIFT
> +/**
> + * set_ptes - Map consecutive pages to a contiguous range of addresses.
> + * @mm: Address space to map the pages into.
> + * @addr: Address to map the first page at.
> + * @ptep: Page table pointer for the first entry.
> + * @pte: Page table entry for the first page.
> + * @nr: Number of pages to map.
> + *
> + * May be overridden by the architecture, or the architecture can define
> + * set_pte() and PFN_PTE_SHIFT.
> + *
> + * Context: The caller holds the page table lock.  The pages all belong
> + * to the same folio.  The PTEs are all in the same PMD.
> + */
> +static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> +		pte_t *ptep, pte_t pte, unsigned int nr)
> +{
> +	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
> +
> +	for (;;) {
> +		set_pte(ptep, pte);
> +		if (--nr == 0)
> +			break;
> +		ptep++;
> +		pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> +	}
> +}
> +#ifndef set_pte_at
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif

Should not there be a build phase call out when both set_ptes() and PFN_PTE_SHIFT
are not defined on a given platform ?

--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -204,6 +204,8 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
 #ifndef set_pte_at
 #define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
 #endif
+#else
+#error "You should define PFN_PTE_SHIFT"
 #endif
 #else
 #define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)

> +#endif> +#else
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif
> +
>  #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
>  extern int ptep_set_access_flags(struct vm_area_struct *vma,
>  				 unsigned long address, pte_t *ptep,
Matthew Wilcox May 25, 2023, 4:06 a.m. UTC | #3 
On Thu, May 25, 2023 at 08:31:14AM +0530, Anshuman Khandual wrote:
> > +#ifndef set_ptes
> > +#ifdef PFN_PTE_SHIFT
> > +/**
> > + * set_ptes - Map consecutive pages to a contiguous range of addresses.
> > + * @mm: Address space to map the pages into.
> > + * @addr: Address to map the first page at.
> > + * @ptep: Page table pointer for the first entry.
> > + * @pte: Page table entry for the first page.
> > + * @nr: Number of pages to map.
> > + *
> > + * May be overridden by the architecture, or the architecture can define
> > + * set_pte() and PFN_PTE_SHIFT.
> > + *
> > + * Context: The caller holds the page table lock.  The pages all belong
> > + * to the same folio.  The PTEs are all in the same PMD.
> > + */
> > +static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> > +		pte_t *ptep, pte_t pte, unsigned int nr)
> > +{
> > +	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
> > +
> > +	for (;;) {
> > +		set_pte(ptep, pte);
> > +		if (--nr == 0)
> > +			break;
> > +		ptep++;
> > +		pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> > +	}
> > +}
> > +#ifndef set_pte_at
> > +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> > +#endif
> 
> Should not there be a build phase call out when both set_ptes() and PFN_PTE_SHIFT
> are not defined on a given platform ?

How does that help?  Either way you get a clear build error.
diff mbox series

Patch

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index c5a51481bbb9..a755fe94b4b4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -172,6 +172,43 @@  static inline int pmd_young(pmd_t pmd)
 }
 #endif
 
+#ifndef set_ptes
+#ifdef PFN_PTE_SHIFT
+/**
+ * set_ptes - Map consecutive pages to a contiguous range of addresses.
+ * @mm: Address space to map the pages into.
+ * @addr: Address to map the first page at.
+ * @ptep: Page table pointer for the first entry.
+ * @pte: Page table entry for the first page.
+ * @nr: Number of pages to map.
+ *
+ * May be overridden by the architecture, or the architecture can define
+ * set_pte() and PFN_PTE_SHIFT.
+ *
+ * Context: The caller holds the page table lock.  The pages all belong
+ * to the same folio.  The PTEs are all in the same PMD.
+ */
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+		pte_t *ptep, pte_t pte, unsigned int nr)
+{
+	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
+
+	for (;;) {
+		set_pte(ptep, pte);
+		if (--nr == 0)
+			break;
+		ptep++;
+		pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
+	}
+}
+#ifndef set_pte_at
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
+#endif
+#endif
+#else
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
+#endif
+
 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 extern int ptep_set_access_flags(struct vm_area_struct *vma,
 				 unsigned long address, pte_t *ptep,