Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932959AbWJIQNf (ORCPT ); Mon, 9 Oct 2006 12:13:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932965AbWJIQNe (ORCPT ); Mon, 9 Oct 2006 12:13:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:65193 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S932959AbWJIQNP (ORCPT ); Mon, 9 Oct 2006 12:13:15 -0400 From: Nick Piggin To: Hugh Dickins , Linux Memory Management Cc: Andrew Morton , Jes Sorensen , Benjamin Herrenschmidt , Linux Kernel , Nick Piggin , Ingo Molnar Message-Id: <20061009140458.13840.92649.sendpatchset@linux.site> In-Reply-To: <20061009140354.13840.71273.sendpatchset@linux.site> References: <20061009140354.13840.71273.sendpatchset@linux.site> Subject: [patch 5/5] mm: merge nopfn with fault handler Date: Mon, 9 Oct 2006 18:13:10 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5804 Lines: 175 Remove ->nopfn and reimplement the only existing handler using ->fault Index: linux-2.6/drivers/char/mspec.c =================================================================== --- linux-2.6.orig/drivers/char/mspec.c +++ linux-2.6/drivers/char/mspec.c @@ -178,24 +178,25 @@ mspec_close(struct vm_area_struct *vma) /* - * mspec_nopfn + * mspec_fault * * Creates a mspec page and maps it to user space. */ -static unsigned long -mspec_nopfn(struct vm_area_struct *vma, unsigned long address) +static struct page * +mspec_fault(struct fault_data *fdata) { unsigned long paddr, maddr; unsigned long pfn; - int index; - struct vma_data *vdata = vma->vm_private_data; + int index = fdata->pgoff; + struct vma_data *vdata = fdata->vma->vm_private_data; - index = (address - vma->vm_start) >> PAGE_SHIFT; maddr = (volatile unsigned long) vdata->maddr[index]; if (maddr == 0) { maddr = uncached_alloc_page(numa_node_id()); - if (maddr == 0) - return NOPFN_OOM; + if (maddr == 0) { + fdata->type = VM_FAULT_OOM; + return NULL; + } spin_lock(&vdata->lock); if (vdata->maddr[index] == 0) { @@ -215,13 +216,21 @@ mspec_nopfn(struct vm_area_struct *vma, pfn = paddr >> PAGE_SHIFT; - return pfn; + fdata->type = VM_FAULT_MINOR; + /* + * vm_insert_pfn can fail with -EBUSY, but in that case it will + * be because another thread has installed the pte first, so it + * is no problem. + */ + vm_insert_pfn(fdata->vma, fdata->address, pfn); + + return NULL; } static struct vm_operations_struct mspec_vm_ops = { .open = mspec_open, .close = mspec_close, - .nopfn = mspec_nopfn + .fault = mspec_fault, }; /* Index: linux-2.6/include/linux/mm.h =================================================================== --- linux-2.6.orig/include/linux/mm.h +++ linux-2.6/include/linux/mm.h @@ -223,7 +223,6 @@ struct vm_operations_struct { void (*close)(struct vm_area_struct * area); struct page * (*fault)(struct fault_data * data); struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int *type); - unsigned long (*nopfn)(struct vm_area_struct * area, unsigned long address); int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock); /* notification that a previously read-only page is about to become @@ -619,12 +618,6 @@ static inline int page_mapped(struct pag #define NOPAGE_OOM ((struct page *) (-1)) /* - * Error return values for the *_nopfn functions - */ -#define NOPFN_SIGBUS ((unsigned long) -1) -#define NOPFN_OOM ((unsigned long) -2) - -/* * Different kinds of faults, as returned by handle_mm_fault(). * Used to decide whether a process gets delivered SIGBUS or * just gets major/minor fault counters bumped up. Index: linux-2.6/mm/memory.c =================================================================== --- linux-2.6.orig/mm/memory.c +++ linux-2.6/mm/memory.c @@ -1278,6 +1278,11 @@ EXPORT_SYMBOL(vm_insert_page); * * This function should only be called from a vm_ops->fault handler, and * in that case the handler should return NULL. + * + * vma cannot be a COW mapping. + * + * As this is called only for pages that do not currently exist, we + * do not need to flush old virtual caches or the TLB. */ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn) { @@ -2335,54 +2340,6 @@ static int do_nonlinear_fault(struct mm_ } /* - * do_no_pfn() tries to create a new page mapping for a page without - * a struct_page backing it - * - * As this is called only for pages that do not currently exist, we - * do not need to flush old virtual caches or the TLB. - * - * We enter with non-exclusive mmap_sem (to exclude vma changes, - * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. - * - * It is expected that the ->nopfn handler always returns the same pfn - * for a given virtual mapping. - * - * Mark this `noinline' to prevent it from bloating the main pagefault code. - */ -static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long address, pte_t *page_table, pmd_t *pmd, - int write_access) -{ - spinlock_t *ptl; - pte_t entry; - unsigned long pfn; - int ret = VM_FAULT_MINOR; - - pte_unmap(page_table); - BUG_ON(!(vma->vm_flags & VM_PFNMAP)); - BUG_ON(is_cow_mapping(vma->vm_flags)); - - pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK); - if (pfn == NOPFN_OOM) - return VM_FAULT_OOM; - if (pfn == NOPFN_SIGBUS) - return VM_FAULT_SIGBUS; - - page_table = pte_offset_map_lock(mm, pmd, address, &ptl); - - /* Only go through if we didn't race with anybody else... */ - if (pte_none(*page_table)) { - entry = pfn_pte(pfn, vma->vm_page_prot); - if (write_access) - entry = maybe_mkwrite(pte_mkdirty(entry), vma); - set_pte_at(mm, address, page_table, entry); - } - pte_unmap_unlock(page_table, ptl); - return ret; -} - -/* * Fault of a previously existing named mapping. Repopulate the pte * from the encoded file_pte if possible. This enables swappable * nonlinear vmas. @@ -2453,9 +2410,6 @@ static inline int handle_pte_fault(struc if (vma->vm_ops->fault || vma->vm_ops->nopage) return do_linear_fault(mm, vma, address, pte, pmd, write_access, entry); - if (unlikely(vma->vm_ops->nopfn)) - return do_no_pfn(mm, vma, address, pte, - pmd, write_access); } return do_anonymous_page(mm, vma, address, pte, pmd, write_access); - 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/