Re: [RFC PATCH 1/8] mm, vmalloc: change iterating a vmlist to find_vm_area()

From: guanxuetao
Date: Mon Dec 10 2012 - 00:25:34 EST


> The purpose of iterating a vmlist is finding vm area with specific
> virtual address. find_vm_area() is provided for this purpose
> and more efficient, because it uses a rbtree.
> So change it.
>
> Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
> Cc: Guan Xuetao <gxt@xxxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>

For UniCore32 bits:
Acked-by: Guan Xuetao <gxt@xxxxxxxxxxxxxxx>

>
> diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
> index de0de0c..862782d 100644
> --- a/arch/tile/mm/pgtable.c
> +++ b/arch/tile/mm/pgtable.c
> @@ -592,12 +592,7 @@ void iounmap(volatile void __iomem *addr_in)
> in parallel. Reuse of the virtual address is prevented by
> leaving it in the global lists until we're done with it.
> cpa takes care of the direct mappings. */
> - read_lock(&vmlist_lock);
> - for (p = vmlist; p; p = p->next) {
> - if (p->addr == addr)
> - break;
> - }
> - read_unlock(&vmlist_lock);
> + p = find_vm_area((void *)addr);
>
> if (!p) {
> pr_err("iounmap: bad address %p\n", addr);
> diff --git a/arch/unicore32/mm/ioremap.c b/arch/unicore32/mm/ioremap.c
> index b7a6055..13068ee 100644
> --- a/arch/unicore32/mm/ioremap.c
> +++ b/arch/unicore32/mm/ioremap.c
> @@ -235,7 +235,7 @@ EXPORT_SYMBOL(__uc32_ioremap_cached);
> void __uc32_iounmap(volatile void __iomem *io_addr)
> {
> void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
> - struct vm_struct **p, *tmp;
> + struct vm_struct *vm;
>
> /*
> * If this is a section based mapping we need to handle it
> @@ -244,17 +244,10 @@ void __uc32_iounmap(volatile void __iomem *io_addr)
> * all the mappings before the area can be reclaimed
> * by someone else.
> */
> - write_lock(&vmlist_lock);
> - for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
> - if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
> - if (tmp->flags & VM_UNICORE_SECTION_MAPPING) {
> - unmap_area_sections((unsigned long)tmp->addr,
> - tmp->size);
> - }
> - break;
> - }
> - }
> - write_unlock(&vmlist_lock);
> + vm = find_vm_area(addr);
> + if (vm && (vm->flags & VM_IOREMAP) &&
> + (vm->flags & VM_UNICORE_SECTION_MAPPING))
> + unmap_area_sections((unsigned long)vm->addr, vm->size);
>
> vunmap(addr);
> }
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index 78fe3f1..9a1e658 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -282,12 +282,7 @@ void iounmap(volatile void __iomem *addr)
> in parallel. Reuse of the virtual address is prevented by
> leaving it in the global lists until we're done with it.
> cpa takes care of the direct mappings. */
> - read_lock(&vmlist_lock);
> - for (p = vmlist; p; p = p->next) {
> - if (p->addr == (void __force *)addr)
> - break;
> - }
> - read_unlock(&vmlist_lock);
> + p = find_vm_area((void __force *)addr);
>
> if (!p) {
> printk(KERN_ERR "iounmap: bad address %p\n", addr);
> --
> 1.7.9.5
>

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