#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/anon_inodes.h>
+#include <linux/migrate.h>
+#include <linux/ramfs.h>
+#include <linux/percpu-refcount.h>
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
#define AIO_RING_PAGES 8
+struct kioctx_table {
+ struct rcu_head rcu;
+ unsigned nr;
+ struct kioctx *table[];
+};
+
+struct kioctx_cpu {
+ unsigned reqs_available;
+};
+
struct kioctx {
- atomic_t users;
+ struct percpu_ref users;
atomic_t dead;
- /* This needs improving */
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.
long nr_pages;
struct rcu_head rcu_head;
- struct work_struct rcu_work;
+ struct work_struct free_work;
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 {
} ____cacheline_aligned_in_smp;
struct page *internal_pages[AIO_RING_PAGES];
+ struct file *aio_ring_file;
+
+ unsigned id;
};
/*------ sysctl variables----*/
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);
+ 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;
+}
+
+#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 = 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;
+}
+#endif
+
+static const struct address_space_operations aio_ctx_aops = {
+ .set_page_dirty = aio_set_page_dirty,
+#if IS_ENABLED(CONFIG_MIGRATION)
+ .migratepage = aio_migratepage,
+#endif
+};
+
static int aio_setup_ring(struct kioctx *ctx)
{
struct aio_ring *ring;
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 *),
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;
}
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
+
+ /* We must do this while still holding mmap_sem for write, as we
+ * need to be protected against userspace attempting to mremap()
+ * or munmap() the ring buffer.
+ */
ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages,
1, 0, ctx->ring_pages, NULL);
+
+ /* Dropping the reference here is safe as the page cache will hold
+ * onto the pages for us. It is also required so that page migration
+ * can unmap the pages and get the right reference count.
+ */
+ for (i = 0; i < ctx->nr_pages; i++)
+ put_page(ctx->ring_pages[i]);
+
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;
}
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 kioctx *ctx, struct 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);
-
- memset(res, 0, sizeof(*res));
- res->obj = (u64)(unsigned long)kiocb->ki_obj.user;
- res->data = kiocb->ki_user_data;
- ret = cancel(kiocb, res);
-
- spin_lock_irq(&ctx->ctx_lock);
-
- return ret;
+ return cancel(kiocb);
}
static void free_ioctx_rcu(struct rcu_head *head)
{
struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
+
+ free_percpu(ctx->cpu);
kmem_cache_free(kioctx_cachep, ctx);
}
* 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(struct work_struct *work)
{
+ struct kioctx *ctx = container_of(work, struct kioctx, free_work);
struct aio_ring *ring;
- struct io_event res;
struct kiocb *req;
- unsigned head, avail;
+ unsigned cpu, avail;
+ DEFINE_WAIT(wait);
spin_lock_irq(&ctx->ctx_lock);
struct kiocb, ki_list);
list_del_init(&req->ki_list);
- kiocb_cancel(ctx, req, &res);
+ kiocb_cancel(ctx, req);
}
spin_unlock_irq(&ctx->ctx_lock);
- ring = kmap_atomic(ctx->ring_pages[0]);
- head = ring->head;
- kunmap_atomic(ring);
+ for_each_possible_cpu(cpu) {
+ struct kioctx_cpu *kcpu = per_cpu_ptr(ctx->cpu, cpu);
- while (atomic_read(&ctx->reqs_active) > 0) {
- wait_event(ctx->wait,
- head != ctx->tail ||
- atomic_read(&ctx->reqs_active) <= 0);
+ atomic_add(kcpu->reqs_available, &ctx->reqs_available);
+ kcpu->reqs_available = 0;
+ }
- avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;
+ while (1) {
+ prepare_to_wait(&ctx->wait, &wait, TASK_UNINTERRUPTIBLE);
- atomic_sub(avail, &ctx->reqs_active);
- head += avail;
- head %= ctx->nr_events;
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ avail = (ring->head <= ring->tail)
+ ? ring->tail - ring->head
+ : ctx->nr_events - ring->head + ring->tail;
+
+ atomic_add(avail, &ctx->reqs_available);
+ ring->head = ring->tail;
+ kunmap_atomic(ring);
+
+ if (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1)
+ break;
+
+ schedule();
}
+ finish_wait(&ctx->wait, &wait);
- WARN_ON(atomic_read(&ctx->reqs_active) < 0);
+ WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr_events - 1);
aio_free_ring(ctx);
call_rcu(&ctx->rcu_head, free_ioctx_rcu);
}
-static void put_ioctx(struct kioctx *ctx)
+static void free_ioctx_ref(struct percpu_ref *ref)
{
- if (unlikely(atomic_dec_and_test(&ctx->users)))
- free_ioctx(ctx);
+ struct kioctx *ctx = container_of(ref, struct kioctx, users);
+
+ INIT_WORK(&ctx->free_work, free_ioctx);
+ schedule_work(&ctx->free_work);
+}
+
+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;
+
+ spin_lock(&mm->ioctx_lock);
+ rcu_read_lock();
+ table = rcu_dereference(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;
+ rcu_read_unlock();
+ spin_unlock(&mm->ioctx_lock);
+
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ ring->id = ctx->id;
+ kunmap_atomic(ring);
+ return 0;
+ }
+
+ new_nr = (table ? table->nr : 1) * 4;
+
+ rcu_read_unlock();
+ spin_unlock(&mm->ioctx_lock);
+
+ table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
+ new_nr, GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ table->nr = new_nr;
+
+ spin_lock(&mm->ioctx_lock);
+ rcu_read_lock();
+ old = rcu_dereference(mm->ioctx_table);
+
+ 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 *));
+
+ rcu_assign_pointer(mm->ioctx_table, table);
+ kfree_rcu(old, rcu);
+ } else {
+ kfree(table);
+ table = old;
+ }
+ }
}
/* 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)))) {
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);
+ if (percpu_ref_init(&ctx->users, free_ioctx_ref))
+ goto out_freectx;
+
spin_lock_init(&ctx->ctx_lock);
spin_lock_init(&ctx->completion_lock);
mutex_init(&ctx->ring_lock);
INIT_LIST_HEAD(&ctx->active_reqs);
+ ctx->cpu = alloc_percpu(struct kioctx_cpu);
+ if (!ctx->cpu)
+ goto out_freeref;
+
if (aio_setup_ring(ctx) < 0)
- goto out_freectx;
+ goto out_freepcpu;
+
+ 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;
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 */
+
+ err = ioctx_add_table(ctx, mm);
+ if (err)
+ goto out_cleanup_put;
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
ctx, ctx->user_id, mm, ctx->nr_events);
return ctx;
+out_cleanup_put:
+ percpu_ref_put(&ctx->users);
out_cleanup:
err = -EAGAIN;
aio_free_ring(ctx);
+out_freepcpu:
+ free_percpu(ctx->cpu);
+out_freeref:
+ free_percpu(ctx->users.pcpu_count);
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);
}
-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 void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx)
{
if (!atomic_xchg(&ctx->dead, 1)) {
- hlist_del_rcu(&ctx->list);
+ struct kioctx_table *table;
+
+ spin_lock(&mm->ioctx_lock);
+ rcu_read_lock();
+ table = rcu_dereference(mm->ioctx_table);
+
+ WARN_ON(ctx != table->table[ctx->id]);
+ table->table[ctx->id] = NULL;
+ rcu_read_unlock();
+ spin_unlock(&mm->ioctx_lock);
+
+ /* percpu_ref_kill() will do the necessary call_rcu() */
+ wake_up_all(&ctx->wait);
/*
* It'd be more correct to do this in free_ioctx(), after all
if (ctx->mmap_size)
vm_munmap(ctx->mmap_base, ctx->mmap_size);
- /* Between hlist_del_rcu() and dropping the initial ref */
- call_rcu(&ctx->rcu_head, kill_ioctx_rcu);
+ percpu_ref_kill(&ctx->users);
}
}
/* wait_on_sync_kiocb:
* Waits on the given sync kiocb to complete.
*/
-ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
+ssize_t wait_on_sync_kiocb(struct kiocb *req)
{
- while (atomic_read(&iocb->ki_users)) {
+ while (!req->ki_ctx) {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (!atomic_read(&iocb->ki_users))
+ if (req->ki_ctx)
break;
io_schedule();
}
__set_current_state(TASK_RUNNING);
- return iocb->ki_user_data;
+ return req->ki_user_data;
}
EXPORT_SYMBOL(wait_on_sync_kiocb);
*/
void exit_aio(struct mm_struct *mm)
{
+ struct kioctx_table *table;
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));
+ unsigned i = 0;
+
+ while (1) {
+ rcu_read_lock();
+ table = rcu_dereference(mm->ioctx_table);
+
+ do {
+ if (!table || i >= table->nr) {
+ rcu_read_unlock();
+ rcu_assign_pointer(mm->ioctx_table, NULL);
+ if (table)
+ kfree(table);
+ return;
+ }
+
+ ctx = table->table[i++];
+ } while (!ctx);
+
+ rcu_read_unlock();
+
/*
* We don't need to bother with munmap() here -
* exit_mmap(mm) is coming and it'll unmap everything.
*/
ctx->mmap_size = 0;
- kill_ioctx(ctx);
+ kill_ioctx(mm, ctx);
+ }
+}
+
+static void put_reqs_available(struct kioctx *ctx, unsigned nr)
+{
+ struct kioctx_cpu *kcpu;
+
+ preempt_disable();
+ 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);
+ }
+
+ preempt_enable();
+}
+
+static bool get_reqs_available(struct kioctx *ctx)
+{
+ struct kioctx_cpu *kcpu;
+ bool ret = false;
+
+ preempt_disable();
+ 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:
+ preempt_enable();
+ return ret;
}
/* 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.
+ * Allocate a slot for an aio request.
+ * Returns NULL if no requests are free.
*/
static inline struct kiocb *aio_get_req(struct kioctx *ctx)
{
struct kiocb *req;
- if (atomic_read(&ctx->reqs_active) >= ctx->nr_events)
+ if (!get_reqs_available(ctx))
return NULL;
- if (atomic_inc_return(&ctx->reqs_active) > ctx->nr_events - 1)
- goto out_put;
-
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;
-
return req;
out_put:
- atomic_dec(&ctx->reqs_active);
+ put_reqs_available(ctx, 1);
return NULL;
}
fput(req->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;
}
* - 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);
+ smp_wmb();
+ iocb->ki_ctx = ERR_PTR(-EXDEV);
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.
+ * need to issue a wakeup after incrementing reqs_available.
*/
rcu_read_lock();
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->completion_lock to prevent other code from messing with the 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
struct io_event __user *event, long nr)
{
struct aio_ring *ring;
- unsigned head, pos;
+ unsigned head, tail, pos;
long ret = 0;
int copy_ret;
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);
+ pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
- if (head == ctx->tail)
+ if (head == tail)
goto out;
while (ret < nr) {
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);
+ pr_debug("%li h%u t%u\n", ret, head, tail);
- atomic_sub(ret, &ctx->reqs_active);
+ put_reqs_available(ctx, ret);
out:
mutex_unlock(&ctx->ring_lock);
if (!IS_ERR(ioctx)) {
ret = put_user(ioctx->user_id, ctxp);
if (ret)
- kill_ioctx(ioctx);
- put_ioctx(ioctx);
+ kill_ioctx(current->mm, ioctx);
+ percpu_ref_put(&ioctx->users);
}
out:
{
struct kioctx *ioctx = lookup_ioctx(ctx);
if (likely(NULL != ioctx)) {
- kill_ioctx(ioctx);
- put_ioctx(ioctx);
+ kill_ioctx(current->mm, ioctx);
+ percpu_ref_put(&ioctx->users);
return 0;
}
pr_debug("EINVAL: io_destroy: invalid context id\n");
return -EINVAL;
}
-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++;
- }
- }
-
- /* 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;
-
- 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;
-
- return ret;
-}
-
-static ssize_t aio_setup_vectored_rw(int rw, struct kiocb *kiocb, bool compat)
+static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb,
+ int rw, char __user *buf,
+ unsigned long *nr_segs,
+ struct iovec **iovec,
+ bool compat)
{
ssize_t ret;
- kiocb->ki_nr_segs = kiocb->ki_nbytes;
+ *nr_segs = kiocb->ki_nbytes;
#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);
+ (struct compat_iovec __user *)buf,
+ *nr_segs, 1, *iovec, iovec);
else
#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);
+ (struct iovec __user *)buf,
+ *nr_segs, 1, *iovec, iovec);
if (ret < 0)
return ret;
return 0;
}
-static ssize_t aio_setup_single_vector(int rw, struct kiocb *kiocb)
+static ssize_t aio_setup_single_vector(struct kiocb *kiocb,
+ int rw, char __user *buf,
+ unsigned long *nr_segs,
+ struct iovec *iovec)
{
- if (unlikely(!access_ok(!rw, kiocb->ki_buf, kiocb->ki_nbytes)))
+ if (unlikely(!access_ok(!rw, 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;
+ iovec->iov_base = buf;
+ iovec->iov_len = kiocb->ki_nbytes;
+ *nr_segs = 1;
return 0;
}
* Performs the initial checks and aio retry method
* setup for the kiocb at the time of 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, bool compat)
{
struct file *file = req->ki_filp;
ssize_t ret;
+ unsigned long nr_segs;
int rw;
fmode_t mode;
aio_rw_op *rw_op;
+ struct iovec inline_vec, *iovec = &inline_vec;
- switch (req->ki_opcode) {
+ switch (opcode) {
case IOCB_CMD_PREAD:
case IOCB_CMD_PREADV:
mode = FMODE_READ;
if (!rw_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);
+ ret = (opcode == IOCB_CMD_PREADV ||
+ opcode == IOCB_CMD_PWRITEV)
+ ? aio_setup_vectored_rw(req, rw, buf, &nr_segs,
+ &iovec, compat)
+ : aio_setup_single_vector(req, rw, buf, &nr_segs,
+ iovec);
if (ret)
return ret;
ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes);
- if (ret < 0)
+ if (ret < 0) {
+ if (iovec != &inline_vec)
+ kfree(iovec);
return ret;
+ }
req->ki_nbytes = ret;
- req->ki_left = ret;
- ret = aio_rw_vect_retry(req, rw, rw_op);
+ /* XXX: move/kill - rw_verify_area()? */
+ /* This matches the pread()/pwrite() logic */
+ if (req->ki_pos < 0) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (rw == WRITE)
+ file_start_write(file);
+
+ ret = rw_op(req, iovec, nr_segs, req->ki_pos);
+
+ if (rw == WRITE)
+ file_end_write(file);
break;
case IOCB_CMD_FDSYNC:
return -EINVAL;
}
+ if (iovec != &inline_vec)
+ kfree(iovec);
+
if (ret != -EIOCBQUEUED) {
/*
* There's no easy way to restart the syscall since other AIO's
req->ki_obj.user = user_iocb;
req->ki_user_data = iocb->aio_data;
req->ki_pos = iocb->aio_offset;
+ req->ki_nbytes = iocb->aio_nbytes;
- 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, iocb->aio_lio_opcode,
+ (char __user *)(unsigned long)iocb->aio_buf,
+ 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);
+ kiocb_free(req);
return ret;
}
}
blk_finish_plug(&plug);
- put_ioctx(ctx);
+ percpu_ref_put(&ctx->users);
return i ? i : ret;
}
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;
u32 key;
kiocb = lookup_kiocb(ctx, iocb, key);
if (kiocb)
- ret = kiocb_cancel(ctx, kiocb, &res);
+ ret = kiocb_cancel(ctx, 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 / cascardo / linux.git / commitdiff