diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/aio.c | 119 |
1 files changed, 108 insertions, 11 deletions
@@ -35,6 +35,9 @@ #include <linux/eventfd.h> #include <linux/blkdev.h> #include <linux/compat.h> +#include <linux/anon_inodes.h> +#include <linux/migrate.h> +#include <linux/ramfs.h> #include <asm/kmap_types.h> #include <asm/uaccess.h> @@ -110,6 +113,7 @@ struct kioctx { } ____cacheline_aligned_in_smp; struct page *internal_pages[AIO_RING_PAGES]; + struct file *aio_ring_file; }; /*------ sysctl variables----*/ @@ -138,15 +142,78 @@ __initcall(aio_setup); static void aio_free_ring(struct kioctx *ctx) { - long i; + int i; + struct file *aio_ring_file = ctx->aio_ring_file; - for (i = 0; i < ctx->nr_pages; i++) + for (i = 0; i < ctx->nr_pages; i++) { + pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, + page_count(ctx->ring_pages[i])); put_page(ctx->ring_pages[i]); + } if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) kfree(ctx->ring_pages); + + if (aio_ring_file) { + truncate_setsize(aio_ring_file->f_inode, 0); + pr_debug("pid(%d) i_nlink=%u d_count=%d d_unhashed=%d i_count=%d\n", + current->pid, aio_ring_file->f_inode->i_nlink, + aio_ring_file->f_path.dentry->d_count, + d_unhashed(aio_ring_file->f_path.dentry), + atomic_read(&aio_ring_file->f_inode->i_count)); + fput(aio_ring_file); + ctx->aio_ring_file = NULL; + } } +static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) +{ + vma->vm_ops = &generic_file_vm_ops; + return 0; +} + +static const struct file_operations aio_ring_fops = { + .mmap = aio_ring_mmap, +}; + +static int aio_set_page_dirty(struct page *page) +{ + return 0; +} + +static int aio_migratepage(struct address_space *mapping, struct page *new, + struct page *old, enum migrate_mode mode) +{ + struct kioctx *ctx = mapping->private_data; + unsigned long flags; + unsigned idx = old->index; + int rc; + + /* Writeback must be complete */ + BUG_ON(PageWriteback(old)); + put_page(old); + + rc = migrate_page_move_mapping(mapping, new, old, NULL, mode); + if (rc != MIGRATEPAGE_SUCCESS) { + get_page(old); + return rc; + } + + get_page(new); + + spin_lock_irqsave(&ctx->completion_lock, flags); + migrate_page_copy(new, old); + ctx->ring_pages[idx] = new; + spin_unlock_irqrestore(&ctx->completion_lock, flags); + + return rc; +} + +static const struct address_space_operations aio_ctx_aops = { + .set_page_dirty = aio_set_page_dirty, + .migratepage = aio_migratepage, +}; + static int aio_setup_ring(struct kioctx *ctx) { struct aio_ring *ring; @@ -154,20 +221,45 @@ static int aio_setup_ring(struct kioctx *ctx) struct mm_struct *mm = current->mm; unsigned long size, populate; int nr_pages; + int i; + struct file *file; /* Compensate for the ring buffer's head/tail overlap entry */ nr_events += 2; /* 1 is required, 2 for good luck */ size = sizeof(struct aio_ring); size += sizeof(struct io_event) * nr_events; - nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; + nr_pages = PFN_UP(size); if (nr_pages < 0) return -EINVAL; - nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); + file = anon_inode_getfile_private("[aio]", &aio_ring_fops, ctx, O_RDWR); + if (IS_ERR(file)) { + ctx->aio_ring_file = NULL; + return -EAGAIN; + } + + file->f_inode->i_mapping->a_ops = &aio_ctx_aops; + file->f_inode->i_mapping->private_data = ctx; + file->f_inode->i_size = PAGE_SIZE * (loff_t)nr_pages; + + for (i = 0; i < nr_pages; i++) { + struct page *page; + page = find_or_create_page(file->f_inode->i_mapping, + i, GFP_HIGHUSER | __GFP_ZERO); + if (!page) + break; + pr_debug("pid(%d) page[%d]->count=%d\n", + current->pid, i, page_count(page)); + SetPageUptodate(page); + SetPageDirty(page); + unlock_page(page); + } + ctx->aio_ring_file = file; + nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) + / sizeof(struct io_event); - ctx->nr_events = 0; ctx->ring_pages = ctx->internal_pages; if (nr_pages > AIO_RING_PAGES) { ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), @@ -178,28 +270,31 @@ static int aio_setup_ring(struct kioctx *ctx) ctx->mmap_size = nr_pages * PAGE_SIZE; pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); + down_write(&mm->mmap_sem); - ctx->mmap_base = do_mmap_pgoff(NULL, 0, ctx->mmap_size, - PROT_READ|PROT_WRITE, - MAP_ANONYMOUS|MAP_PRIVATE, 0, &populate); + ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_POPULATE, 0, &populate); if (IS_ERR((void *)ctx->mmap_base)) { up_write(&mm->mmap_sem); ctx->mmap_size = 0; aio_free_ring(ctx); return -EAGAIN; } + up_write(&mm->mmap_sem); + + mm_populate(ctx->mmap_base, populate); pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages, 1, 0, ctx->ring_pages, NULL); - up_write(&mm->mmap_sem); + for (i = 0; i < ctx->nr_pages; i++) + put_page(ctx->ring_pages[i]); if (unlikely(ctx->nr_pages != nr_pages)) { aio_free_ring(ctx); return -EAGAIN; } - if (populate) - mm_populate(ctx->mmap_base, populate); ctx->user_id = ctx->mmap_base; ctx->nr_events = nr_events; /* trusted copy */ @@ -399,6 +494,8 @@ out_cleanup: err = -EAGAIN; aio_free_ring(ctx); out_freectx: + if (ctx->aio_ring_file) + fput(ctx->aio_ring_file); kmem_cache_free(kioctx_cachep, ctx); pr_debug("error allocating ioctx %d\n", err); return ERR_PTR(err); |