#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mmu_context.h>
+#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/aio.h>
#include <linux/eventfd.h>
#include <linux/blkdev.h>
#include <linux/compat.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>
+#include "internal.h"
+
#define AIO_RING_MAGIC 0xa10a10a1
#define AIO_RING_COMPAT_FEATURES 1
#define AIO_RING_INCOMPAT_FEATURES 0
struct aio_ring {
unsigned id; /* kernel internal index number */
unsigned nr; /* number of io_events */
- unsigned head;
+ unsigned head; /* Written to by userland or under ring_lock
+ * mutex by aio_read_events_ring(). */
unsigned tail;
unsigned magic;
#define AIO_RING_PAGES 8
+struct kioctx_table {
+ struct rcu_head rcu;
+ unsigned nr;
+ struct kioctx *table[];
+};
+
+struct kioctx_cpu {
+ unsigned reqs_available;
+};
+
+struct ctx_rq_wait {
+ struct completion comp;
+ atomic_t count;
+};
+
struct kioctx {
- atomic_t users;
+ struct percpu_ref users;
atomic_t dead;
- /* This needs improving */
+ struct percpu_ref reqs;
+
unsigned long user_id;
- struct hlist_node list;
+ struct __percpu kioctx_cpu *cpu;
+
+ /*
+ * For percpu reqs_available, number of slots we move to/from global
+ * counter at a time:
+ */
+ unsigned req_batch;
/*
* This is what userspace passed to io_setup(), it's not used for
* anything but counting against the global max_reqs quota.
struct page **ring_pages;
long nr_pages;
- struct rcu_head rcu_head;
- struct work_struct rcu_work;
+ struct work_struct free_work;
+
+ /*
+ * signals when all in-flight requests are done
+ */
+ struct ctx_rq_wait *rq_wait;
struct {
- atomic_t reqs_active;
+ /*
+ * This counts the number of available slots in the ringbuffer,
+ * so we avoid overflowing it: it's decremented (if positive)
+ * when allocating a kiocb and incremented when the resulting
+ * io_event is pulled off the ringbuffer.
+ *
+ * We batch accesses to it with a percpu version.
+ */
+ atomic_t reqs_available;
} ____cacheline_aligned_in_smp;
struct {
struct {
unsigned tail;
+ unsigned completed_events;
spinlock_t completion_lock;
} ____cacheline_aligned_in_smp;
struct page *internal_pages[AIO_RING_PAGES];
+ struct file *aio_ring_file;
+
+ unsigned id;
+};
+
+/*
+ * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
+ * cancelled or completed (this makes a certain amount of sense because
+ * successful cancellation - io_cancel() - does deliver the completion to
+ * userspace).
+ *
+ * And since most things don't implement kiocb cancellation and we'd really like
+ * kiocb completion to be lockless when possible, we use ki_cancel to
+ * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
+ * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
+ */
+#define KIOCB_CANCELLED ((void *) (~0ULL))
+
+struct aio_kiocb {
+ struct kiocb common;
+
+ struct kioctx *ki_ctx;
+ kiocb_cancel_fn *ki_cancel;
+
+ struct iocb __user *ki_user_iocb; /* user's aiocb */
+ __u64 ki_user_data; /* user's data for completion */
+
+ struct list_head ki_list; /* the aio core uses this
+ * for cancellation */
+
+ /*
+ * If the aio_resfd field of the userspace iocb is not zero,
+ * this is the underlying eventfd context to deliver events to.
+ */
+ struct eventfd_ctx *ki_eventfd;
};
/*------ sysctl variables----*/
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 (IS_ERR(inode))
+ return ERR_CAST(inode);
+
+ 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;
+ 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,
+ };
+ struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, &ops,
+ AIO_RING_MAGIC);
+
+ if (!IS_ERR(root))
+ root->d_sb->s_iflags |= SB_I_NOEXEC;
+ return root;
+}
+
/* 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)
{
- kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
+ 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(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page));
}
__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)
{
- long i;
+ int i;
+
+ /* Disconnect the kiotx from the ring file. This prevents future
+ * accesses to the kioctx from page migration.
+ */
+ put_aio_ring_file(ctx);
- for (i = 0; i < ctx->nr_pages; i++)
- put_page(ctx->ring_pages[i]);
+ for (i = 0; i < ctx->nr_pages; i++) {
+ struct page *page;
+ pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
+ page_count(ctx->ring_pages[i]));
+ page = ctx->ring_pages[i];
+ if (!page)
+ continue;
+ ctx->ring_pages[i] = NULL;
+ put_page(page);
+ }
- if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages)
+ if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
kfree(ctx->ring_pages);
+ ctx->ring_pages = NULL;
+ }
+}
+
+static int aio_ring_mremap(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct mm_struct *mm = vma->vm_mm;
+ struct kioctx_table *table;
+ int i, res = -EINVAL;
+
+ spin_lock(&mm->ioctx_lock);
+ rcu_read_lock();
+ table = rcu_dereference(mm->ioctx_table);
+ for (i = 0; i < table->nr; i++) {
+ struct kioctx *ctx;
+
+ ctx = table->table[i];
+ if (ctx && ctx->aio_ring_file == file) {
+ if (!atomic_read(&ctx->dead)) {
+ ctx->user_id = ctx->mmap_base = vma->vm_start;
+ res = 0;
+ }
+ break;
+ }
+ }
+
+ rcu_read_unlock();
+ spin_unlock(&mm->ioctx_lock);
+ return res;
+}
+
+static const struct vm_operations_struct aio_ring_vm_ops = {
+ .mremap = aio_ring_mremap,
+#if IS_ENABLED(CONFIG_MMU)
+ .fault = filemap_fault,
+ .map_pages = filemap_map_pages,
+ .page_mkwrite = filemap_page_mkwrite,
+#endif
+};
+
+static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ vma->vm_flags |= VM_DONTEXPAND;
+ vma->vm_ops = &aio_ring_vm_ops;
+ return 0;
+}
+
+static const struct file_operations aio_ring_fops = {
+ .mmap = aio_ring_mmap,
+};
+
+#if IS_ENABLED(CONFIG_MIGRATION)
+static int aio_migratepage(struct address_space *mapping, struct page *new,
+ struct page *old, enum migrate_mode mode)
+{
+ struct kioctx *ctx;
+ unsigned long flags;
+ pgoff_t idx;
+ int rc;
+
+ rc = 0;
+
+ /* mapping->private_lock here protects against the kioctx teardown. */
+ spin_lock(&mapping->private_lock);
+ ctx = mapping->private_data;
+ if (!ctx) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ /* The ring_lock mutex. The prevents aio_read_events() from writing
+ * to the ring's head, and prevents page migration from mucking in
+ * a partially initialized kiotx.
+ */
+ if (!mutex_trylock(&ctx->ring_lock)) {
+ rc = -EAGAIN;
+ goto out;
+ }
+
+ idx = old->index;
+ if (idx < (pgoff_t)ctx->nr_pages) {
+ /* Make sure the old page hasn't already been changed */
+ if (ctx->ring_pages[idx] != old)
+ rc = -EAGAIN;
+ } else
+ rc = -EINVAL;
+
+ if (rc != 0)
+ goto out_unlock;
+
+ /* Writeback must be complete */
+ BUG_ON(PageWriteback(old));
+ get_page(new);
+
+ rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
+ if (rc != MIGRATEPAGE_SUCCESS) {
+ put_page(new);
+ goto out_unlock;
+ }
+
+ /* Take completion_lock to prevent other writes to the ring buffer
+ * while the old page is copied to the new. This prevents new
+ * events from being lost.
+ */
+ spin_lock_irqsave(&ctx->completion_lock, flags);
+ migrate_page_copy(new, old);
+ BUG_ON(ctx->ring_pages[idx] != old);
+ ctx->ring_pages[idx] = new;
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+
+ /* The old page is no longer accessible. */
+ put_page(old);
+
+out_unlock:
+ mutex_unlock(&ctx->ring_lock);
+out:
+ spin_unlock(&mapping->private_lock);
+ return rc;
}
+#endif
+
+static const struct address_space_operations aio_ctx_aops = {
+ .set_page_dirty = __set_page_dirty_no_writeback,
+#if IS_ENABLED(CONFIG_MIGRATION)
+ .migratepage = aio_migratepage,
+#endif
+};
static int aio_setup_ring(struct kioctx *ctx)
{
struct aio_ring *ring;
unsigned nr_events = ctx->max_reqs;
struct mm_struct *mm = current->mm;
- unsigned long size, populate;
+ unsigned long size, unused;
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 = aio_private_file(ctx, nr_pages);
+ if (IS_ERR(file)) {
+ ctx->aio_ring_file = NULL;
+ return -ENOMEM;
+ }
+
+ 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 *),
GFP_KERNEL);
- if (!ctx->ring_pages)
+ if (!ctx->ring_pages) {
+ put_aio_ring_file(ctx);
return -ENOMEM;
+ }
+ }
+
+ 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);
+ unlock_page(page);
+
+ ctx->ring_pages[i] = page;
+ }
+ ctx->nr_pages = i;
+
+ if (unlikely(i != nr_pages)) {
+ aio_free_ring(ctx);
+ return -ENOMEM;
}
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, 0, &unused);
+ up_write(&mm->mmap_sem);
if (IS_ERR((void *)ctx->mmap_base)) {
- up_write(&mm->mmap_sem);
ctx->mmap_size = 0;
aio_free_ring(ctx);
- return -EAGAIN;
+ return -ENOMEM;
}
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);
-
- 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 */
ring = kmap_atomic(ctx->ring_pages[0]);
ring->nr = nr_events; /* user copy */
- ring->id = ctx->user_id;
+ ring->id = ~0U;
ring->head = ring->tail = 0;
ring->magic = AIO_RING_MAGIC;
ring->compat_features = AIO_RING_COMPAT_FEATURES;
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
-void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
+void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
{
+ struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, common);
struct kioctx *ctx = req->ki_ctx;
unsigned long flags;
}
EXPORT_SYMBOL(kiocb_set_cancel_fn);
-static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb,
- struct io_event *res)
+static int kiocb_cancel(struct aio_kiocb *kiocb)
{
kiocb_cancel_fn *old, *cancel;
- int ret = -EINVAL;
/*
* Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it
cancel = ACCESS_ONCE(kiocb->ki_cancel);
do {
if (!cancel || cancel == KIOCB_CANCELLED)
- return ret;
+ return -EINVAL;
old = cancel;
cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED);
} while (cancel != old);
- atomic_inc(&kiocb->ki_users);
- spin_unlock_irq(&ctx->ctx_lock);
+ return cancel(&kiocb->common);
+}
- memset(res, 0, sizeof(*res));
- res->obj = (u64)(unsigned long)kiocb->ki_obj.user;
- res->data = kiocb->ki_user_data;
- ret = cancel(kiocb, res);
+static void free_ioctx(struct work_struct *work)
+{
+ struct kioctx *ctx = container_of(work, struct kioctx, free_work);
- spin_lock_irq(&ctx->ctx_lock);
+ pr_debug("freeing %p\n", ctx);
- return ret;
+ aio_free_ring(ctx);
+ free_percpu(ctx->cpu);
+ percpu_ref_exit(&ctx->reqs);
+ percpu_ref_exit(&ctx->users);
+ kmem_cache_free(kioctx_cachep, ctx);
}
-static void free_ioctx_rcu(struct rcu_head *head)
+static void free_ioctx_reqs(struct percpu_ref *ref)
{
- struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
- kmem_cache_free(kioctx_cachep, ctx);
+ struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
+
+ /* At this point we know that there are no any in-flight requests */
+ if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
+ complete(&ctx->rq_wait->comp);
+
+ INIT_WORK(&ctx->free_work, free_ioctx);
+ schedule_work(&ctx->free_work);
}
/*
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
* now it's safe to cancel any that need to be.
*/
-static void free_ioctx(struct kioctx *ctx)
+static void free_ioctx_users(struct percpu_ref *ref)
{
- struct aio_ring *ring;
- struct io_event res;
- struct kiocb *req;
- unsigned head, avail;
+ struct kioctx *ctx = container_of(ref, struct kioctx, users);
+ struct aio_kiocb *req;
spin_lock_irq(&ctx->ctx_lock);
while (!list_empty(&ctx->active_reqs)) {
req = list_first_entry(&ctx->active_reqs,
- struct kiocb, ki_list);
+ struct aio_kiocb, ki_list);
list_del_init(&req->ki_list);
- kiocb_cancel(ctx, req, &res);
+ kiocb_cancel(req);
}
spin_unlock_irq(&ctx->ctx_lock);
- ring = kmap_atomic(ctx->ring_pages[0]);
- head = ring->head;
- kunmap_atomic(ring);
-
- while (atomic_read(&ctx->reqs_active) > 0) {
- wait_event(ctx->wait,
- head != ctx->tail ||
- atomic_read(&ctx->reqs_active) <= 0);
+ percpu_ref_kill(&ctx->reqs);
+ percpu_ref_put(&ctx->reqs);
+}
- avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;
+static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
+{
+ unsigned i, new_nr;
+ struct kioctx_table *table, *old;
+ struct aio_ring *ring;
- atomic_sub(avail, &ctx->reqs_active);
- head += avail;
- head %= ctx->nr_events;
- }
+ spin_lock(&mm->ioctx_lock);
+ table = rcu_dereference_raw(mm->ioctx_table);
+
+ while (1) {
+ if (table)
+ for (i = 0; i < table->nr; i++)
+ if (!table->table[i]) {
+ ctx->id = i;
+ table->table[i] = ctx;
+ spin_unlock(&mm->ioctx_lock);
+
+ /* While kioctx setup is in progress,
+ * we are protected from page migration
+ * changes ring_pages by ->ring_lock.
+ */
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ ring->id = ctx->id;
+ kunmap_atomic(ring);
+ return 0;
+ }
+
+ new_nr = (table ? table->nr : 1) * 4;
+ spin_unlock(&mm->ioctx_lock);
+
+ table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
+ new_nr, GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
- WARN_ON(atomic_read(&ctx->reqs_active) < 0);
+ table->nr = new_nr;
- aio_free_ring(ctx);
+ spin_lock(&mm->ioctx_lock);
+ old = rcu_dereference_raw(mm->ioctx_table);
- pr_debug("freeing %p\n", ctx);
+ if (!old) {
+ rcu_assign_pointer(mm->ioctx_table, table);
+ } else if (table->nr > old->nr) {
+ memcpy(table->table, old->table,
+ old->nr * sizeof(struct kioctx *));
- /*
- * Here the call_rcu() is between the wait_event() for reqs_active to
- * hit 0, and freeing the ioctx.
- *
- * aio_complete() decrements reqs_active, but it has to touch the ioctx
- * after to issue a wakeup so we use rcu.
- */
- call_rcu(&ctx->rcu_head, free_ioctx_rcu);
+ rcu_assign_pointer(mm->ioctx_table, table);
+ kfree_rcu(old, rcu);
+ } else {
+ kfree(table);
+ table = old;
+ }
+ }
}
-static void put_ioctx(struct kioctx *ctx)
+static void aio_nr_sub(unsigned nr)
{
- if (unlikely(atomic_dec_and_test(&ctx->users)))
- free_ioctx(ctx);
+ spin_lock(&aio_nr_lock);
+ if (WARN_ON(aio_nr - nr > aio_nr))
+ aio_nr = 0;
+ else
+ aio_nr -= nr;
+ spin_unlock(&aio_nr_lock);
}
/* ioctx_alloc
struct kioctx *ctx;
int err = -ENOMEM;
+ /*
+ * We keep track of the number of available ringbuffer slots, to prevent
+ * overflow (reqs_available), and we also use percpu counters for this.
+ *
+ * So since up to half the slots might be on other cpu's percpu counters
+ * and unavailable, double nr_events so userspace sees what they
+ * expected: additionally, we move req_batch slots to/from percpu
+ * counters at a time, so make sure that isn't 0:
+ */
+ nr_events = max(nr_events, num_possible_cpus() * 4);
+ nr_events *= 2;
+
/* Prevent overflows */
- if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
- (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
+ if (nr_events > (0x10000000U / sizeof(struct io_event))) {
pr_debug("ENOMEM: nr_events too high\n");
return ERR_PTR(-EINVAL);
}
- if (!nr_events || (unsigned long)nr_events > aio_max_nr)
+ if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL))
return ERR_PTR(-EAGAIN);
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
ctx->max_reqs = nr_events;
- atomic_set(&ctx->users, 2);
- atomic_set(&ctx->dead, 0);
spin_lock_init(&ctx->ctx_lock);
spin_lock_init(&ctx->completion_lock);
mutex_init(&ctx->ring_lock);
+ /* Protect against page migration throughout kiotx setup by keeping
+ * the ring_lock mutex held until setup is complete. */
+ mutex_lock(&ctx->ring_lock);
init_waitqueue_head(&ctx->wait);
INIT_LIST_HEAD(&ctx->active_reqs);
- if (aio_setup_ring(ctx) < 0)
- goto out_freectx;
+ if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
+ goto err;
+
+ if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
+ goto err;
+
+ ctx->cpu = alloc_percpu(struct kioctx_cpu);
+ if (!ctx->cpu)
+ goto err;
+
+ err = aio_setup_ring(ctx);
+ if (err < 0)
+ goto err;
+
+ atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
+ ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
+ if (ctx->req_batch < 1)
+ ctx->req_batch = 1;
/* limit the number of system wide aios */
spin_lock(&aio_nr_lock);
- if (aio_nr + nr_events > aio_max_nr ||
+ if (aio_nr + nr_events > (aio_max_nr * 2UL) ||
aio_nr + nr_events < aio_nr) {
spin_unlock(&aio_nr_lock);
- goto out_cleanup;
+ err = -EAGAIN;
+ goto err_ctx;
}
aio_nr += ctx->max_reqs;
spin_unlock(&aio_nr_lock);
- /* now link into global list. */
- spin_lock(&mm->ioctx_lock);
- hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
- spin_unlock(&mm->ioctx_lock);
+ percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
+ percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
+
+ err = ioctx_add_table(ctx, mm);
+ if (err)
+ goto err_cleanup;
+
+ /* Release the ring_lock mutex now that all setup is complete. */
+ mutex_unlock(&ctx->ring_lock);
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
ctx, ctx->user_id, mm, ctx->nr_events);
return ctx;
-out_cleanup:
- err = -EAGAIN;
+err_cleanup:
+ aio_nr_sub(ctx->max_reqs);
+err_ctx:
+ atomic_set(&ctx->dead, 1);
+ if (ctx->mmap_size)
+ vm_munmap(ctx->mmap_base, ctx->mmap_size);
aio_free_ring(ctx);
-out_freectx:
+err:
+ mutex_unlock(&ctx->ring_lock);
+ free_percpu(ctx->cpu);
+ percpu_ref_exit(&ctx->reqs);
+ percpu_ref_exit(&ctx->users);
kmem_cache_free(kioctx_cachep, ctx);
pr_debug("error allocating ioctx %d\n", err);
return ERR_PTR(err);
}
-static void kill_ioctx_work(struct work_struct *work)
-{
- struct kioctx *ctx = container_of(work, struct kioctx, rcu_work);
-
- wake_up_all(&ctx->wait);
- put_ioctx(ctx);
-}
-
-static void kill_ioctx_rcu(struct rcu_head *head)
-{
- struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
-
- INIT_WORK(&ctx->rcu_work, kill_ioctx_work);
- schedule_work(&ctx->rcu_work);
-}
-
/* kill_ioctx
* Cancels all outstanding aio requests on an aio context. Used
* when the processes owning a context have all exited to encourage
* the rapid destruction of the kioctx.
*/
-static void kill_ioctx(struct kioctx *ctx)
+static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
+ struct ctx_rq_wait *wait)
{
- if (!atomic_xchg(&ctx->dead, 1)) {
- hlist_del_rcu(&ctx->list);
+ struct kioctx_table *table;
- /*
- * It'd be more correct to do this in free_ioctx(), after all
- * the outstanding kiocbs have finished - but by then io_destroy
- * has already returned, so io_setup() could potentially return
- * -EAGAIN with no ioctxs actually in use (as far as userspace
- * could tell).
- */
- spin_lock(&aio_nr_lock);
- BUG_ON(aio_nr - ctx->max_reqs > aio_nr);
- aio_nr -= ctx->max_reqs;
- spin_unlock(&aio_nr_lock);
+ spin_lock(&mm->ioctx_lock);
+ if (atomic_xchg(&ctx->dead, 1)) {
+ spin_unlock(&mm->ioctx_lock);
+ return -EINVAL;
+ }
- if (ctx->mmap_size)
- vm_munmap(ctx->mmap_base, ctx->mmap_size);
+ table = rcu_dereference_raw(mm->ioctx_table);
+ WARN_ON(ctx != table->table[ctx->id]);
+ table->table[ctx->id] = NULL;
+ spin_unlock(&mm->ioctx_lock);
- /* Between hlist_del_rcu() and dropping the initial ref */
- call_rcu(&ctx->rcu_head, kill_ioctx_rcu);
- }
-}
+ /* percpu_ref_kill() will do the necessary call_rcu() */
+ wake_up_all(&ctx->wait);
-/* wait_on_sync_kiocb:
- * Waits on the given sync kiocb to complete.
- */
-ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
-{
- while (atomic_read(&iocb->ki_users)) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!atomic_read(&iocb->ki_users))
- break;
- io_schedule();
- }
- __set_current_state(TASK_RUNNING);
- return iocb->ki_user_data;
+ /*
+ * It'd be more correct to do this in free_ioctx(), after all
+ * the outstanding kiocbs have finished - but by then io_destroy
+ * has already returned, so io_setup() could potentially return
+ * -EAGAIN with no ioctxs actually in use (as far as userspace
+ * could tell).
+ */
+ aio_nr_sub(ctx->max_reqs);
+
+ if (ctx->mmap_size)
+ vm_munmap(ctx->mmap_base, ctx->mmap_size);
+
+ ctx->rq_wait = wait;
+ percpu_ref_kill(&ctx->users);
+ return 0;
}
-EXPORT_SYMBOL(wait_on_sync_kiocb);
/*
* exit_aio: called when the last user of mm goes away. At this point, there is
*/
void exit_aio(struct mm_struct *mm)
{
- struct kioctx *ctx;
- struct hlist_node *n;
-
- hlist_for_each_entry_safe(ctx, n, &mm->ioctx_list, list) {
- if (1 != atomic_read(&ctx->users))
- printk(KERN_DEBUG
- "exit_aio:ioctx still alive: %d %d %d\n",
- atomic_read(&ctx->users),
- atomic_read(&ctx->dead),
- atomic_read(&ctx->reqs_active));
+ struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
+ struct ctx_rq_wait wait;
+ int i, skipped;
+
+ if (!table)
+ return;
+
+ atomic_set(&wait.count, table->nr);
+ init_completion(&wait.comp);
+
+ skipped = 0;
+ for (i = 0; i < table->nr; ++i) {
+ struct kioctx *ctx = table->table[i];
+
+ if (!ctx) {
+ skipped++;
+ continue;
+ }
+
/*
- * We don't need to bother with munmap() here -
- * exit_mmap(mm) is coming and it'll unmap everything.
- * Since aio_free_ring() uses non-zero ->mmap_size
- * as indicator that it needs to unmap the area,
- * just set it to 0; aio_free_ring() is the only
- * place that uses ->mmap_size, so it's safe.
+ * We don't need to bother with munmap() here - exit_mmap(mm)
+ * is coming and it'll unmap everything. And we simply can't,
+ * this is not necessarily our ->mm.
+ * Since kill_ioctx() uses non-zero ->mmap_size as indicator
+ * that it needs to unmap the area, just set it to 0.
*/
ctx->mmap_size = 0;
+ kill_ioctx(mm, ctx, &wait);
+ }
- kill_ioctx(ctx);
+ if (!atomic_sub_and_test(skipped, &wait.count)) {
+ /* Wait until all IO for the context are done. */
+ wait_for_completion(&wait.comp);
}
+
+ RCU_INIT_POINTER(mm->ioctx_table, NULL);
+ kfree(table);
}
-/* aio_get_req
- * Allocate a slot for an aio request. Increments the ki_users count
- * of the kioctx so that the kioctx stays around until all requests are
- * complete. Returns NULL if no requests are free.
- *
- * Returns with kiocb->ki_users set to 2. The io submit code path holds
- * an extra reference while submitting the i/o.
- * This prevents races between the aio code path referencing the
- * req (after submitting it) and aio_complete() freeing the req.
+static void put_reqs_available(struct kioctx *ctx, unsigned nr)
+{
+ struct kioctx_cpu *kcpu;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ kcpu = this_cpu_ptr(ctx->cpu);
+ kcpu->reqs_available += nr;
+
+ while (kcpu->reqs_available >= ctx->req_batch * 2) {
+ kcpu->reqs_available -= ctx->req_batch;
+ atomic_add(ctx->req_batch, &ctx->reqs_available);
+ }
+
+ local_irq_restore(flags);
+}
+
+static bool get_reqs_available(struct kioctx *ctx)
+{
+ struct kioctx_cpu *kcpu;
+ bool ret = false;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ kcpu = this_cpu_ptr(ctx->cpu);
+ if (!kcpu->reqs_available) {
+ int old, avail = atomic_read(&ctx->reqs_available);
+
+ do {
+ if (avail < ctx->req_batch)
+ goto out;
+
+ old = avail;
+ avail = atomic_cmpxchg(&ctx->reqs_available,
+ avail, avail - ctx->req_batch);
+ } while (avail != old);
+
+ kcpu->reqs_available += ctx->req_batch;
+ }
+
+ ret = true;
+ kcpu->reqs_available--;
+out:
+ local_irq_restore(flags);
+ return ret;
+}
+
+/* refill_reqs_available
+ * Updates the reqs_available reference counts used for tracking the
+ * number of free slots in the completion ring. This can be called
+ * from aio_complete() (to optimistically update reqs_available) or
+ * from aio_get_req() (the we're out of events case). It must be
+ * called holding ctx->completion_lock.
*/
-static inline struct kiocb *aio_get_req(struct kioctx *ctx)
+static void refill_reqs_available(struct kioctx *ctx, unsigned head,
+ unsigned tail)
{
- struct kiocb *req;
+ unsigned events_in_ring, completed;
- if (atomic_read(&ctx->reqs_active) >= ctx->nr_events)
- return NULL;
+ /* Clamp head since userland can write to it. */
+ head %= ctx->nr_events;
+ if (head <= tail)
+ events_in_ring = tail - head;
+ else
+ events_in_ring = ctx->nr_events - (head - tail);
- if (atomic_inc_return(&ctx->reqs_active) > ctx->nr_events - 1)
- goto out_put;
+ completed = ctx->completed_events;
+ if (events_in_ring < completed)
+ completed -= events_in_ring;
+ else
+ completed = 0;
+
+ if (!completed)
+ return;
+
+ ctx->completed_events -= completed;
+ put_reqs_available(ctx, completed);
+}
+
+/* user_refill_reqs_available
+ * Called to refill reqs_available when aio_get_req() encounters an
+ * out of space in the completion ring.
+ */
+static void user_refill_reqs_available(struct kioctx *ctx)
+{
+ spin_lock_irq(&ctx->completion_lock);
+ if (ctx->completed_events) {
+ struct aio_ring *ring;
+ unsigned head;
+
+ /* Access of ring->head may race with aio_read_events_ring()
+ * here, but that's okay since whether we read the old version
+ * or the new version, and either will be valid. The important
+ * part is that head cannot pass tail since we prevent
+ * aio_complete() from updating tail by holding
+ * ctx->completion_lock. Even if head is invalid, the check
+ * against ctx->completed_events below will make sure we do the
+ * safe/right thing.
+ */
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ head = ring->head;
+ kunmap_atomic(ring);
+
+ refill_reqs_available(ctx, head, ctx->tail);
+ }
+
+ spin_unlock_irq(&ctx->completion_lock);
+}
+
+/* aio_get_req
+ * Allocate a slot for an aio request.
+ * Returns NULL if no requests are free.
+ */
+static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
+{
+ struct aio_kiocb *req;
+
+ if (!get_reqs_available(ctx)) {
+ user_refill_reqs_available(ctx);
+ if (!get_reqs_available(ctx))
+ return NULL;
+ }
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
if (unlikely(!req))
goto out_put;
- atomic_set(&req->ki_users, 2);
- req->ki_ctx = ctx;
+ percpu_ref_get(&ctx->reqs);
+ req->ki_ctx = ctx;
return req;
out_put:
- atomic_dec(&ctx->reqs_active);
+ put_reqs_available(ctx, 1);
return NULL;
}
-static void kiocb_free(struct kiocb *req)
+static void kiocb_free(struct aio_kiocb *req)
{
- if (req->ki_filp)
- fput(req->ki_filp);
+ if (req->common.ki_filp)
+ fput(req->common.ki_filp);
if (req->ki_eventfd != NULL)
eventfd_ctx_put(req->ki_eventfd);
- if (req->ki_dtor)
- req->ki_dtor(req);
- if (req->ki_iovec != &req->ki_inline_vec)
- kfree(req->ki_iovec);
kmem_cache_free(kiocb_cachep, req);
}
-void aio_put_req(struct kiocb *req)
-{
- if (atomic_dec_and_test(&req->ki_users))
- kiocb_free(req);
-}
-EXPORT_SYMBOL(aio_put_req);
-
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
{
+ struct aio_ring __user *ring = (void __user *)ctx_id;
struct mm_struct *mm = current->mm;
struct kioctx *ctx, *ret = NULL;
+ struct kioctx_table *table;
+ unsigned id;
+
+ if (get_user(id, &ring->id))
+ return NULL;
rcu_read_lock();
+ table = rcu_dereference(mm->ioctx_table);
- hlist_for_each_entry_rcu(ctx, &mm->ioctx_list, list) {
- if (ctx->user_id == ctx_id) {
- atomic_inc(&ctx->users);
- ret = ctx;
- break;
- }
- }
+ if (!table || id >= table->nr)
+ goto out;
+ ctx = table->table[id];
+ if (ctx && ctx->user_id == ctx_id) {
+ percpu_ref_get(&ctx->users);
+ ret = ctx;
+ }
+out:
rcu_read_unlock();
return ret;
}
/* aio_complete
* Called when the io request on the given iocb is complete.
*/
-void aio_complete(struct kiocb *iocb, long res, long res2)
+static void aio_complete(struct kiocb *kiocb, long res, long res2)
{
+ struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, common);
struct kioctx *ctx = iocb->ki_ctx;
struct aio_ring *ring;
struct io_event *ev_page, *event;
+ unsigned tail, pos, head;
unsigned long flags;
- unsigned tail, pos;
/*
* Special case handling for sync iocbs:
* ref, no other paths have a way to get another ref
* - the sync task helpfully left a reference to itself in the iocb
*/
- if (is_sync_kiocb(iocb)) {
- BUG_ON(atomic_read(&iocb->ki_users) != 1);
- iocb->ki_user_data = res;
- atomic_set(&iocb->ki_users, 0);
- wake_up_process(iocb->ki_obj.tsk);
- return;
- }
-
- /*
- * Take rcu_read_lock() in case the kioctx is being destroyed, as we
- * need to issue a wakeup after decrementing reqs_active.
- */
- rcu_read_lock();
+ BUG_ON(is_sync_kiocb(kiocb));
if (iocb->ki_list.next) {
unsigned long flags;
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
}
- /*
- * cancelled requests don't get events, userland was given one
- * when the event got cancelled.
- */
- if (unlikely(xchg(&iocb->ki_cancel,
- KIOCB_CANCELLED) == KIOCB_CANCELLED)) {
- atomic_dec(&ctx->reqs_active);
- /* Still need the wake_up in case free_ioctx is waiting */
- goto put_rq;
- }
-
/*
* Add a completion event to the ring buffer. Must be done holding
- * ctx->ctx_lock to prevent other code from messing with the tail
+ * ctx->completion_lock to prevent other code from messing with the tail
* pointer since we might be called from irq context.
*/
spin_lock_irqsave(&ctx->completion_lock, flags);
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
- event->obj = (u64)(unsigned long)iocb->ki_obj.user;
+ event->obj = (u64)(unsigned long)iocb->ki_user_iocb;
event->data = iocb->ki_user_data;
event->res = res;
event->res2 = res2;
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
- ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
+ ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data,
res, res2);
/* after flagging the request as done, we
ctx->tail = tail;
ring = kmap_atomic(ctx->ring_pages[0]);
+ head = ring->head;
ring->tail = tail;
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
+ ctx->completed_events++;
+ if (ctx->completed_events > 1)
+ refill_reqs_available(ctx, head, tail);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
pr_debug("added to ring %p at [%u]\n", iocb, tail);
if (iocb->ki_eventfd != NULL)
eventfd_signal(iocb->ki_eventfd, 1);
-put_rq:
/* everything turned out well, dispose of the aiocb. */
- aio_put_req(iocb);
+ kiocb_free(iocb);
/*
* We have to order our ring_info tail store above and test
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
- rcu_read_unlock();
+ percpu_ref_put(&ctx->reqs);
}
-EXPORT_SYMBOL(aio_complete);
-/* aio_read_events
+/* aio_read_events_ring
* Pull an event off of the ioctx's event ring. Returns the number of
* events fetched
*/
struct io_event __user *event, long nr)
{
struct aio_ring *ring;
- unsigned head, pos;
+ unsigned head, tail, pos;
long ret = 0;
int copy_ret;
+ /*
+ * The mutex can block and wake us up and that will cause
+ * wait_event_interruptible_hrtimeout() to schedule without sleeping
+ * and repeat. This should be rare enough that it doesn't cause
+ * peformance issues. See the comment in read_events() for more detail.
+ */
+ sched_annotate_sleep();
mutex_lock(&ctx->ring_lock);
+ /* Access to ->ring_pages here is protected by ctx->ring_lock. */
ring = kmap_atomic(ctx->ring_pages[0]);
head = ring->head;
+ tail = ring->tail;
kunmap_atomic(ring);
- pr_debug("h%u t%u m%u\n", head, ctx->tail, ctx->nr_events);
+ /*
+ * Ensure that once we've read the current tail pointer, that
+ * we also see the events that were stored up to the tail.
+ */
+ smp_rmb();
+
+ pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
- if (head == ctx->tail)
+ if (head == tail)
goto out;
+ head %= ctx->nr_events;
+ tail %= ctx->nr_events;
+
while (ret < nr) {
long avail;
struct io_event *ev;
struct page *page;
- avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;
- if (head == ctx->tail)
+ avail = (head <= tail ? tail : ctx->nr_events) - head;
+ if (head == tail)
break;
avail = min(avail, nr - ret);
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
- pr_debug("%li h%u t%u\n", ret, head, ctx->tail);
-
- atomic_sub(ret, &ctx->reqs_active);
+ pr_debug("%li h%u t%u\n", ret, head, tail);
out:
mutex_unlock(&ctx->ring_lock);
* the ringbuffer empty. So in practice we should be ok, but it's
* something to be aware of when touching this code.
*/
- wait_event_interruptible_hrtimeout(ctx->wait,
- aio_read_events(ctx, min_nr, nr, event, &ret), until);
+ if (until.tv64 == 0)
+ aio_read_events(ctx, min_nr, nr, event, &ret);
+ else
+ wait_event_interruptible_hrtimeout(ctx->wait,
+ aio_read_events(ctx, min_nr, nr, event, &ret),
+ until);
if (!ret && signal_pending(current))
ret = -EINTR;
ret = -EINVAL;
if (unlikely(ctx || nr_events == 0)) {
- pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
+ pr_debug("EINVAL: ctx %lu nr_events %u\n",
ctx, nr_events);
goto out;
}
if (!IS_ERR(ioctx)) {
ret = put_user(ioctx->user_id, ctxp);
if (ret)
- kill_ioctx(ioctx);
- put_ioctx(ioctx);
+ kill_ioctx(current->mm, ioctx, NULL);
+ percpu_ref_put(&ioctx->users);
}
out:
{
struct kioctx *ioctx = lookup_ioctx(ctx);
if (likely(NULL != ioctx)) {
- kill_ioctx(ioctx);
- put_ioctx(ioctx);
- return 0;
- }
- pr_debug("EINVAL: io_destroy: invalid context id\n");
- return -EINVAL;
-}
+ struct ctx_rq_wait wait;
+ int ret;
-static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
-{
- struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
-
- BUG_ON(ret <= 0);
-
- while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
- ssize_t this = min((ssize_t)iov->iov_len, ret);
- iov->iov_base += this;
- iov->iov_len -= this;
- iocb->ki_left -= this;
- ret -= this;
- if (iov->iov_len == 0) {
- iocb->ki_cur_seg++;
- iov++;
- }
- }
+ init_completion(&wait.comp);
+ atomic_set(&wait.count, 1);
- /* the caller should not have done more io than what fit in
- * the remaining iovecs */
- BUG_ON(ret > 0 && iocb->ki_left == 0);
-}
-
-typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *,
- unsigned long, loff_t);
-
-static ssize_t aio_rw_vect_retry(struct kiocb *iocb, int rw, aio_rw_op *rw_op)
-{
- struct file *file = iocb->ki_filp;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- ssize_t ret = 0;
-
- /* This matches the pread()/pwrite() logic */
- if (iocb->ki_pos < 0)
- return -EINVAL;
+ /* Pass requests_done to kill_ioctx() where it can be set
+ * in a thread-safe way. If we try to set it here then we have
+ * a race condition if two io_destroy() called simultaneously.
+ */
+ ret = kill_ioctx(current->mm, ioctx, &wait);
+ percpu_ref_put(&ioctx->users);
- if (rw == WRITE)
- file_start_write(file);
- do {
- ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
- iocb->ki_nr_segs - iocb->ki_cur_seg,
- iocb->ki_pos);
- if (ret > 0)
- aio_advance_iovec(iocb, ret);
-
- /* retry all partial writes. retry partial reads as long as its a
- * regular file. */
- } while (ret > 0 && iocb->ki_left > 0 &&
- (rw == WRITE ||
- (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
- if (rw == WRITE)
- file_end_write(file);
-
- /* This means we must have transferred all that we could */
- /* No need to retry anymore */
- if ((ret == 0) || (iocb->ki_left == 0))
- ret = iocb->ki_nbytes - iocb->ki_left;
-
- /* If we managed to write some out we return that, rather than
- * the eventual error. */
- if (rw == WRITE
- && ret < 0 && ret != -EIOCBQUEUED
- && iocb->ki_nbytes - iocb->ki_left)
- ret = iocb->ki_nbytes - iocb->ki_left;
+ /* Wait until all IO for the context are done. Otherwise kernel
+ * keep using user-space buffers even if user thinks the context
+ * is destroyed.
+ */
+ if (!ret)
+ wait_for_completion(&wait.comp);
- return ret;
+ return ret;
+ }
+ pr_debug("EINVAL: invalid context id\n");
+ return -EINVAL;
}
-static ssize_t aio_setup_vectored_rw(int rw, struct kiocb *kiocb, bool compat)
-{
- ssize_t ret;
-
- kiocb->ki_nr_segs = kiocb->ki_nbytes;
+typedef ssize_t (rw_iter_op)(struct kiocb *, struct iov_iter *);
+static int aio_setup_vectored_rw(int rw, char __user *buf, size_t len,
+ struct iovec **iovec,
+ bool compat,
+ struct iov_iter *iter)
+{
#ifdef CONFIG_COMPAT
if (compat)
- ret = compat_rw_copy_check_uvector(rw,
- (struct compat_iovec __user *)kiocb->ki_buf,
- kiocb->ki_nr_segs, 1, &kiocb->ki_inline_vec,
- &kiocb->ki_iovec);
- else
+ return compat_import_iovec(rw,
+ (struct compat_iovec __user *)buf,
+ len, UIO_FASTIOV, iovec, iter);
#endif
- ret = rw_copy_check_uvector(rw,
- (struct iovec __user *)kiocb->ki_buf,
- kiocb->ki_nr_segs, 1, &kiocb->ki_inline_vec,
- &kiocb->ki_iovec);
- if (ret < 0)
- return ret;
-
- /* ki_nbytes now reflect bytes instead of segs */
- kiocb->ki_nbytes = ret;
- return 0;
-}
-
-static ssize_t aio_setup_single_vector(int rw, struct kiocb *kiocb)
-{
- if (unlikely(!access_ok(!rw, kiocb->ki_buf, kiocb->ki_nbytes)))
- return -EFAULT;
-
- kiocb->ki_iovec = &kiocb->ki_inline_vec;
- kiocb->ki_iovec->iov_base = kiocb->ki_buf;
- kiocb->ki_iovec->iov_len = kiocb->ki_nbytes;
- kiocb->ki_nr_segs = 1;
- return 0;
+ return import_iovec(rw, (struct iovec __user *)buf,
+ len, UIO_FASTIOV, iovec, iter);
}
/*
- * aio_setup_iocb:
- * Performs the initial checks and aio retry method
- * setup for the kiocb at the time of io submission.
+ * aio_run_iocb:
+ * Performs the initial checks and io submission.
*/
-static ssize_t aio_run_iocb(struct kiocb *req, bool compat)
+static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode,
+ char __user *buf, size_t len, bool compat)
{
struct file *file = req->ki_filp;
ssize_t ret;
int rw;
fmode_t mode;
- aio_rw_op *rw_op;
+ rw_iter_op *iter_op;
+ struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
+ struct iov_iter iter;
- switch (req->ki_opcode) {
+ switch (opcode) {
case IOCB_CMD_PREAD:
case IOCB_CMD_PREADV:
mode = FMODE_READ;
rw = READ;
- rw_op = file->f_op->aio_read;
+ iter_op = file->f_op->read_iter;
goto rw_common;
case IOCB_CMD_PWRITE:
case IOCB_CMD_PWRITEV:
mode = FMODE_WRITE;
rw = WRITE;
- rw_op = file->f_op->aio_write;
+ iter_op = file->f_op->write_iter;
goto rw_common;
rw_common:
if (unlikely(!(file->f_mode & mode)))
return -EBADF;
- if (!rw_op)
+ if (!iter_op)
return -EINVAL;
- ret = (req->ki_opcode == IOCB_CMD_PREADV ||
- req->ki_opcode == IOCB_CMD_PWRITEV)
- ? aio_setup_vectored_rw(rw, req, compat)
- : aio_setup_single_vector(rw, req);
- if (ret)
+ if (opcode == IOCB_CMD_PREADV || opcode == IOCB_CMD_PWRITEV)
+ ret = aio_setup_vectored_rw(rw, buf, len,
+ &iovec, compat, &iter);
+ else {
+ ret = import_single_range(rw, buf, len, iovec, &iter);
+ iovec = NULL;
+ }
+ if (!ret)
+ ret = rw_verify_area(rw, file, &req->ki_pos,
+ iov_iter_count(&iter));
+ if (ret < 0) {
+ kfree(iovec);
return ret;
+ }
- ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes);
- if (ret < 0)
- return ret;
+ len = ret;
- req->ki_nbytes = ret;
- req->ki_left = ret;
+ if (rw == WRITE)
+ file_start_write(file);
- ret = aio_rw_vect_retry(req, rw, rw_op);
+ ret = iter_op(req, &iter);
+
+ if (rw == WRITE)
+ file_end_write(file);
+ kfree(iovec);
break;
case IOCB_CMD_FDSYNC:
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
struct iocb *iocb, bool compat)
{
- struct kiocb *req;
+ struct aio_kiocb *req;
ssize_t ret;
/* enforce forwards compatibility on users */
(iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
((ssize_t)iocb->aio_nbytes < 0)
)) {
- pr_debug("EINVAL: io_submit: overflow check\n");
+ pr_debug("EINVAL: overflow check\n");
return -EINVAL;
}
if (unlikely(!req))
return -EAGAIN;
- req->ki_filp = fget(iocb->aio_fildes);
- if (unlikely(!req->ki_filp)) {
+ req->common.ki_filp = fget(iocb->aio_fildes);
+ if (unlikely(!req->common.ki_filp)) {
ret = -EBADF;
goto out_put_req;
}
+ req->common.ki_pos = iocb->aio_offset;
+ req->common.ki_complete = aio_complete;
+ req->common.ki_flags = iocb_flags(req->common.ki_filp);
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
/*
req->ki_eventfd = NULL;
goto out_put_req;
}
+
+ req->common.ki_flags |= IOCB_EVENTFD;
}
ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
goto out_put_req;
}
- req->ki_obj.user = user_iocb;
+ req->ki_user_iocb = user_iocb;
req->ki_user_data = iocb->aio_data;
- req->ki_pos = iocb->aio_offset;
-
- req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
- req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
- req->ki_opcode = iocb->aio_lio_opcode;
- ret = aio_run_iocb(req, compat);
+ ret = aio_run_iocb(&req->common, iocb->aio_lio_opcode,
+ (char __user *)(unsigned long)iocb->aio_buf,
+ iocb->aio_nbytes,
+ compat);
if (ret)
goto out_put_req;
- aio_put_req(req); /* drop extra ref to req */
return 0;
out_put_req:
- atomic_dec(&ctx->reqs_active);
- aio_put_req(req); /* drop extra ref to req */
- aio_put_req(req); /* drop i/o ref to req */
+ put_reqs_available(ctx, 1);
+ percpu_ref_put(&ctx->reqs);
+ kiocb_free(req);
return ret;
}
}
blk_finish_plug(&plug);
- put_ioctx(ctx);
+ percpu_ref_put(&ctx->users);
return i ? i : ret;
}
/* lookup_kiocb
* Finds a given iocb for cancellation.
*/
-static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
- u32 key)
+static struct aio_kiocb *
+lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key)
{
- struct list_head *pos;
+ struct aio_kiocb *kiocb;
assert_spin_locked(&ctx->ctx_lock);
return NULL;
/* TODO: use a hash or array, this sucks. */
- list_for_each(pos, &ctx->active_reqs) {
- struct kiocb *kiocb = list_kiocb(pos);
- if (kiocb->ki_obj.user == iocb)
+ list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
+ if (kiocb->ki_user_iocb == iocb)
return kiocb;
}
return NULL;
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
struct io_event __user *, result)
{
- struct io_event res;
struct kioctx *ctx;
- struct kiocb *kiocb;
+ struct aio_kiocb *kiocb;
u32 key;
int ret;
kiocb = lookup_kiocb(ctx, iocb, key);
if (kiocb)
- ret = kiocb_cancel(ctx, kiocb, &res);
+ ret = kiocb_cancel(kiocb);
else
ret = -EINVAL;
spin_unlock_irq(&ctx->ctx_lock);
if (!ret) {
- /* Cancellation succeeded -- copy the result
- * into the user's buffer.
+ /*
+ * The result argument is no longer used - the io_event is
+ * always delivered via the ring buffer. -EINPROGRESS indicates
+ * cancellation is progress:
*/
- if (copy_to_user(result, &res, sizeof(res)))
- ret = -EFAULT;
+ ret = -EINPROGRESS;
}
- put_ioctx(ctx);
+ percpu_ref_put(&ctx->users);
return ret;
}
if (likely(ioctx)) {
if (likely(min_nr <= nr && min_nr >= 0))
ret = read_events(ioctx, min_nr, nr, events, timeout);
- put_ioctx(ioctx);
+ percpu_ref_put(&ioctx->users);
}
return ret;
}
projects / firefly-linux-kernel-4.4.55.git / blobdiff