X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Ffilemap_xip.c;h=32132f3cd641a9bdea85c101aebfb51315ee0456;hb=535131e6925b4a95f321148ad7293f496e0e58d7;hp=9dd9fbb7513947227d184c10c60cd2b731779ea8;hpb=51e6ed23fc95c3e710d8a98717924ccb2571aa66;p=linux-2.6 diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 9dd9fbb751..32132f3cd6 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -13,8 +13,31 @@ #include #include #include +#include #include -#include "filemap.h" + +/* + * We do use our own empty page to avoid interference with other users + * of ZERO_PAGE(), such as /dev/zero + */ +static struct page *__xip_sparse_page; + +static struct page *xip_sparse_page(void) +{ + if (!__xip_sparse_page) { + unsigned long zeroes = get_zeroed_page(GFP_HIGHUSER); + if (zeroes) { + static DEFINE_SPINLOCK(xip_alloc_lock); + spin_lock(&xip_alloc_lock); + if (!__xip_sparse_page) + __xip_sparse_page = virt_to_page(zeroes); + else + free_page(zeroes); + spin_unlock(&xip_alloc_lock); + } + } + return __xip_sparse_page; +} /* * This is a file read routine for execute in place files, and uses @@ -135,34 +158,12 @@ xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) } EXPORT_SYMBOL_GPL(xip_file_read); -ssize_t -xip_file_sendfile(struct file *in_file, loff_t *ppos, - size_t count, read_actor_t actor, void *target) -{ - read_descriptor_t desc; - - if (!count) - return 0; - - desc.written = 0; - desc.count = count; - desc.arg.data = target; - desc.error = 0; - - do_xip_mapping_read(in_file->f_mapping, &in_file->f_ra, in_file, - ppos, &desc, actor); - if (desc.written) - return desc.written; - return desc.error; -} -EXPORT_SYMBOL_GPL(xip_file_sendfile); - /* * __xip_unmap is invoked from xip_unmap and * xip_write * * This function walks all vmas of the address_space and unmaps the - * ZERO_PAGE when found at pgoff. Should it go in rmap.c? + * __xip_sparse_page when found at pgoff. */ static void __xip_unmap (struct address_space * mapping, @@ -177,13 +178,16 @@ __xip_unmap (struct address_space * mapping, spinlock_t *ptl; struct page *page; + page = __xip_sparse_page; + if (!page) + return; + spin_lock(&mapping->i_mmap_lock); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { mm = vma->vm_mm; address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); BUG_ON(address < vma->vm_start || address >= vma->vm_end); - page = ZERO_PAGE(0); pte = page_check_address(page, mm, address, &ptl); if (pte) { /* Nuke the page table entry. */ @@ -200,62 +204,58 @@ __xip_unmap (struct address_space * mapping, } /* - * xip_nopage() is invoked via the vma operations vector for a + * xip_fault() is invoked via the vma operations vector for a * mapped memory region to read in file data during a page fault. * - * This function is derived from filemap_nopage, but used for execute in place + * This function is derived from filemap_fault, but used for execute in place */ -static struct page * -xip_file_nopage(struct vm_area_struct * area, - unsigned long address, - int *type) +static int xip_file_fault(struct vm_area_struct *area, struct vm_fault *vmf) { struct file *file = area->vm_file; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; struct page *page; - unsigned long size, pgoff, endoff; + pgoff_t size; - pgoff = ((address - area->vm_start) >> PAGE_CACHE_SHIFT) - + area->vm_pgoff; - endoff = ((area->vm_end - area->vm_start) >> PAGE_CACHE_SHIFT) - + area->vm_pgoff; + /* XXX: are VM_FAULT_ codes OK? */ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - if (pgoff >= size) { - return NULL; - } + if (vmf->pgoff >= size) + return VM_FAULT_SIGBUS; - page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0); - if (!IS_ERR(page)) { + page = mapping->a_ops->get_xip_page(mapping, + vmf->pgoff*(PAGE_SIZE/512), 0); + if (!IS_ERR(page)) goto out; - } if (PTR_ERR(page) != -ENODATA) - return NULL; + return VM_FAULT_OOM; /* sparse block */ if ((area->vm_flags & (VM_WRITE | VM_MAYWRITE)) && (area->vm_flags & (VM_SHARED| VM_MAYSHARE)) && (!(mapping->host->i_sb->s_flags & MS_RDONLY))) { /* maybe shared writable, allocate new block */ - page = mapping->a_ops->get_xip_page (mapping, - pgoff*(PAGE_SIZE/512), 1); + page = mapping->a_ops->get_xip_page(mapping, + vmf->pgoff*(PAGE_SIZE/512), 1); if (IS_ERR(page)) - return NULL; + return VM_FAULT_SIGBUS; /* unmap page at pgoff from all other vmas */ - __xip_unmap(mapping, pgoff); + __xip_unmap(mapping, vmf->pgoff); } else { - /* not shared and writable, use ZERO_PAGE() */ - page = ZERO_PAGE(0); + /* not shared and writable, use xip_sparse_page() */ + page = xip_sparse_page(); + if (!page) + return VM_FAULT_OOM; } out: page_cache_get(page); - return page; + vmf->page = page; + return 0; } static struct vm_operations_struct xip_file_vm_ops = { - .nopage = xip_file_nopage, + .fault = xip_file_fault, }; int xip_file_mmap(struct file * file, struct vm_area_struct * vma) @@ -264,6 +264,7 @@ int xip_file_mmap(struct file * file, struct vm_area_struct * vma) file_accessed(file); vma->vm_ops = &xip_file_vm_ops; + vma->vm_flags |= VM_CAN_NONLINEAR; return 0; } EXPORT_SYMBOL_GPL(xip_file_mmap); @@ -286,6 +287,7 @@ __xip_file_write(struct file *filp, const char __user *buf, unsigned long index; unsigned long offset; size_t copied; + char *kaddr; offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ index = pos >> PAGE_CACHE_SHIFT; @@ -293,14 +295,6 @@ __xip_file_write(struct file *filp, const char __user *buf, if (bytes > count) bytes = count; - /* - * Bring in the user page that we will copy from _first_. - * Otherwise there's a nasty deadlock on copying from the - * same page as we're writing to, without it being marked - * up-to-date. - */ - fault_in_pages_readable(buf, bytes); - page = a_ops->get_xip_page(mapping, index*(PAGE_SIZE/512), 0); if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) { @@ -317,8 +311,13 @@ __xip_file_write(struct file *filp, const char __user *buf, break; } - copied = filemap_copy_from_user(page, offset, buf, bytes); + fault_in_pages_readable(buf, bytes); + kaddr = kmap_atomic(page, KM_USER0); + copied = bytes - + __copy_from_user_inatomic_nocache(kaddr, buf, bytes); + kunmap_atomic(kaddr, KM_USER0); flush_dcache_page(page); + if (likely(copied > 0)) { status = copied; @@ -408,7 +407,6 @@ xip_truncate_page(struct address_space *mapping, loff_t from) unsigned blocksize; unsigned length; struct page *page; - void *kaddr; BUG_ON(!mapping->a_ops->get_xip_page); @@ -432,11 +430,7 @@ xip_truncate_page(struct address_space *mapping, loff_t from) else return PTR_ERR(page); } - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, length); - kunmap_atomic(kaddr, KM_USER0); - - flush_dcache_page(page); + zero_user_page(page, offset, length, KM_USER0); return 0; } EXPORT_SYMBOL_GPL(xip_truncate_page);