#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 <linux/percpu-refcount.h>
+#include <linux/mount.h>
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
static struct kmem_cache *kiocb_cachep;
static struct kmem_cache *kioctx_cachep;
+static struct vfsmount *aio_mnt;
+
+static const struct file_operations aio_ring_fops;
+static const struct address_space_operations aio_ctx_aops;
+
+static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
+{
+ struct qstr this = QSTR_INIT("[aio]", 5);
+ struct file *file;
+ struct path path;
+ struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ inode->i_mapping->a_ops = &aio_ctx_aops;
+ inode->i_mapping->private_data = ctx;
+ inode->i_size = PAGE_SIZE * nr_pages;
+
+ path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
+ if (!path.dentry) {
+ iput(inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ path.mnt = mntget(aio_mnt);
+
+ d_instantiate(path.dentry, inode);
+ file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops);
+ if (IS_ERR(file)) {
+ path_put(&path);
+ return file;
+ }
+
+ file->f_flags = O_RDWR;
+ file->private_data = ctx;
+ return file;
+}
+
+static struct dentry *aio_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ static const struct dentry_operations ops = {
+ .d_dname = simple_dname,
+ };
+ return mount_pseudo(fs_type, "aio:", NULL, &ops, 0xa10a10a1);
+}
+
/* aio_setup
* Creates the slab caches used by the aio routines, panic on
* failure as this is done early during the boot sequence.
*/
static int __init aio_setup(void)
{
+ static struct file_system_type aio_fs = {
+ .name = "aio",
+ .mount = aio_mount,
+ .kill_sb = kill_anon_super,
+ };
+ aio_mnt = kern_mount(&aio_fs);
+ if (IS_ERR(aio_mnt))
+ panic("Failed to create aio fs mount.");
+
kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
}
__initcall(aio_setup);
+static void put_aio_ring_file(struct kioctx *ctx)
+{
+ struct file *aio_ring_file = ctx->aio_ring_file;
+ if (aio_ring_file) {
+ truncate_setsize(aio_ring_file->f_inode, 0);
+
+ /* Prevent further access to the kioctx from migratepages */
+ spin_lock(&aio_ring_file->f_inode->i_mapping->private_lock);
+ aio_ring_file->f_inode->i_mapping->private_data = NULL;
+ ctx->aio_ring_file = NULL;
+ spin_unlock(&aio_ring_file->f_inode->i_mapping->private_lock);
+
+ fput(aio_ring_file);
+ }
+}
+
static void aio_free_ring(struct kioctx *ctx)
{
int i;
- struct file *aio_ring_file = ctx->aio_ring_file;
for (i = 0; i < ctx->nr_pages; i++) {
pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
put_page(ctx->ring_pages[i]);
}
+ put_aio_ring_file(ctx);
+
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);
- fput(aio_ring_file);
- ctx->aio_ring_file = NULL;
- }
}
static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
static int aio_migratepage(struct address_space *mapping, struct page *new,
struct page *old, enum migrate_mode mode)
{
- struct kioctx *ctx = mapping->private_data;
+ struct kioctx *ctx;
unsigned long flags;
- unsigned idx = old->index;
int rc;
/* Writeback must be complete */
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);
+ /* We can potentially race against kioctx teardown here. Use the
+ * address_space's private data lock to protect the mapping's
+ * private_data.
+ */
+ spin_lock(&mapping->private_lock);
+ ctx = mapping->private_data;
+ if (ctx) {
+ pgoff_t idx;
+ spin_lock_irqsave(&ctx->completion_lock, flags);
+ migrate_page_copy(new, old);
+ idx = old->index;
+ if (idx < (pgoff_t)ctx->nr_pages)
+ ctx->ring_pages[idx] = new;
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+ } else
+ rc = -EBUSY;
+ spin_unlock(&mapping->private_lock);
return rc;
}
if (nr_pages < 0)
return -EINVAL;
- file = anon_inode_getfile_private("[aio]", &aio_ring_fops, ctx, O_RDWR);
+ file = aio_private_file(ctx, nr_pages);
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,
out_freeref:
free_percpu(ctx->users.pcpu_count);
out_freectx:
- if (ctx->aio_ring_file)
- fput(ctx->aio_ring_file);
+ put_aio_ring_file(ctx);
kmem_cache_free(kioctx_cachep, ctx);
pr_debug("error allocating ioctx %d\n", err);
return ERR_PTR(err);
projects / firefly-linux-kernel-4.4.55.git / blobdiff