lkml.org 
[lkml]   [2006]   [Mar]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[RFC PATCH 30/35] Add generic_page_range() function
    Add a new mm function generic_page_range() which applies a given
    function to every pte in a given virtual address range in a given mm
    structure. This is a generic alternative to cut-and-pasting the Linux
    idiomatic pagetable walking code in every place that a sequence of
    PTEs must be accessed.

    Although this interface is intended to be useful in a wide range of
    situations, it is currently used specifically by several Xen
    subsystems, for example: to ensure that pagetables have been allocated
    for a virtual address range, and to construct batched special
    pagetable update requests to map I/O memory (in ioremap()).

    Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
    Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
    Signed-off-by: Chris Wright <chrisw@sous-sol.org>
    ---
    include/linux/mm.h | 5 ++
    mm/memory.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 95 insertions(+)

    --- xen-subarch-2.6.orig/include/linux/mm.h
    +++ xen-subarch-2.6/include/linux/mm.h
    @@ -1013,6 +1013,11 @@ struct page *follow_page(struct vm_area_
    #define FOLL_GET 0x04 /* do get_page on page */
    #define FOLL_ANON 0x08 /* give ZERO_PAGE if no pgtable */

    +typedef int (*pte_fn_t)(pte_t *pte, struct page *pte_page, unsigned long addr,
    + void *data);
    +extern int generic_page_range(struct mm_struct *mm, unsigned long address,
    + unsigned long size, pte_fn_t fn, void *data);
    +
    #ifdef CONFIG_PROC_FS
    void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
    #else
    --- xen-subarch-2.6.orig/mm/memory.c
    +++ xen-subarch-2.6/mm/memory.c
    @@ -1359,6 +1359,96 @@ int remap_pfn_range(struct vm_area_struc
    }
    EXPORT_SYMBOL(remap_pfn_range);

    +static inline int generic_pte_range(struct mm_struct *mm, pmd_t *pmd,
    + unsigned long addr, unsigned long end,
    + pte_fn_t fn, void *data)
    +{
    + pte_t *pte;
    + int err;
    + struct page *pte_page;
    +
    + pte = (mm == &init_mm) ?
    + pte_alloc_kernel(pmd, addr) :
    + pte_alloc_map(mm, pmd, addr);
    + if (!pte)
    + return -ENOMEM;
    +
    + pte_page = pmd_page(*pmd);
    +
    + do {
    + err = fn(pte, pte_page, addr, data);
    + if (err)
    + break;
    + } while (pte++, addr += PAGE_SIZE, addr != end);
    +
    + if (mm != &init_mm)
    + pte_unmap(pte-1);
    + return err;
    +}
    +
    +static inline int generic_pmd_range(struct mm_struct *mm, pud_t *pud,
    + unsigned long addr, unsigned long end,
    + pte_fn_t fn, void *data)
    +{
    + pmd_t *pmd;
    + unsigned long next;
    + int err;
    +
    + pmd = pmd_alloc(mm, pud, addr);
    + if (!pmd)
    + return -ENOMEM;
    + do {
    + next = pmd_addr_end(addr, end);
    + err = generic_pte_range(mm, pmd, addr, next, fn, data);
    + if (err)
    + break;
    + } while (pmd++, addr = next, addr != end);
    + return err;
    +}
    +
    +static inline int generic_pud_range(struct mm_struct *mm, pgd_t *pgd,
    + unsigned long addr, unsigned long end,
    + pte_fn_t fn, void *data)
    +{
    + pud_t *pud;
    + unsigned long next;
    + int err;
    +
    + pud = pud_alloc(mm, pgd, addr);
    + if (!pud)
    + return -ENOMEM;
    + do {
    + next = pud_addr_end(addr, end);
    + err = generic_pmd_range(mm, pud, addr, next, fn, data);
    + if (err)
    + break;
    + } while (pud++, addr = next, addr != end);
    + return err;
    +}
    +
    +/*
    + * Scan a region of virtual memory, filling in page tables as necessary
    + * and calling a provided function on each leaf page table.
    + */
    +int generic_page_range(struct mm_struct *mm, unsigned long addr,
    + unsigned long size, pte_fn_t fn, void *data)
    +{
    + pgd_t *pgd;
    + unsigned long next;
    + unsigned long end = addr + size;
    + int err;
    +
    + BUG_ON(addr >= end);
    + pgd = pgd_offset(mm, addr);
    + do {
    + next = pgd_addr_end(addr, end);
    + err = generic_pud_range(mm, pgd, addr, next, fn, data);
    + if (err)
    + break;
    + } while (pgd++, addr = next, addr != end);
    + return err;
    +}
    +
    /*
    * handle_pte_fault chooses page fault handler according to an entry
    * which was read non-atomically. Before making any commitment, on
    --
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2006-03-22 07:41    [W:0.028 / U:1.676 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site