#include <linux/aio_abi.h>
#include <linux/module.h>
#include <linux/syscalls.h>
+#include <linux/backing-dev.h>
#include <linux/uio.h>
#define DEBUG 0
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
+#include <linux/mmu_context.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/aio.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/eventfd.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/hash.h>
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
-#include <asm/mmu_context.h>
#if DEBUG > 1
#define dprintk printk
static DEFINE_SPINLOCK(fput_lock);
static LIST_HEAD(fput_head);
+#define AIO_BATCH_HASH_BITS 3 /* allocated on-stack, so don't go crazy */
+#define AIO_BATCH_HASH_SIZE (1 << AIO_BATCH_HASH_BITS)
+struct aio_batch_entry {
+ struct hlist_node list;
+ struct address_space *mapping;
+};
+mempool_t *abe_pool;
+
static void aio_kick_handler(struct work_struct *);
static void aio_queue_work(struct kioctx *);
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
aio_wq = create_workqueue("aio");
+ abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry));
+ BUG_ON(!abe_pool);
pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
return 0;
}
+__initcall(aio_setup);
static void aio_free_ring(struct kioctx *ctx)
{
kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
} while(0)
+static void ctx_rcu_free(struct rcu_head *head)
+{
+ struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
+ unsigned nr_events = ctx->max_reqs;
+
+ kmem_cache_free(kioctx_cachep, ctx);
+
+ if (nr_events) {
+ spin_lock(&aio_nr_lock);
+ BUG_ON(aio_nr - nr_events > aio_nr);
+ aio_nr -= nr_events;
+ spin_unlock(&aio_nr_lock);
+ }
+}
+
+/* __put_ioctx
+ * Called when the last user of an aio context has gone away,
+ * and the struct needs to be freed.
+ */
+static void __put_ioctx(struct kioctx *ctx)
+{
+ BUG_ON(ctx->reqs_active);
+
+ cancel_delayed_work(&ctx->wq);
+ cancel_work_sync(&ctx->wq.work);
+ aio_free_ring(ctx);
+ mmdrop(ctx->mm);
+ ctx->mm = NULL;
+ pr_debug("__put_ioctx: freeing %p\n", ctx);
+ call_rcu(&ctx->rcu_head, ctx_rcu_free);
+}
+
+#define get_ioctx(kioctx) do { \
+ BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
+ atomic_inc(&(kioctx)->users); \
+} while (0)
+#define put_ioctx(kioctx) do { \
+ BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
+ if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
+ __put_ioctx(kioctx); \
+} while (0)
+
/* ioctx_alloc
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
*/
{
struct mm_struct *mm;
struct kioctx *ctx;
+ int did_sync = 0;
/* Prevent overflows */
if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
goto out_freectx;
/* limit the number of system wide aios */
- spin_lock(&aio_nr_lock);
- if (aio_nr + ctx->max_reqs > aio_max_nr ||
- aio_nr + ctx->max_reqs < aio_nr)
- ctx->max_reqs = 0;
- else
- aio_nr += ctx->max_reqs;
- spin_unlock(&aio_nr_lock);
+ do {
+ spin_lock_bh(&aio_nr_lock);
+ if (aio_nr + nr_events > aio_max_nr ||
+ aio_nr + nr_events < aio_nr)
+ ctx->max_reqs = 0;
+ else
+ aio_nr += ctx->max_reqs;
+ spin_unlock_bh(&aio_nr_lock);
+ if (ctx->max_reqs || did_sync)
+ break;
+
+ /* wait for rcu callbacks to have completed before giving up */
+ synchronize_rcu();
+ did_sync = 1;
+ ctx->max_reqs = nr_events;
+ } while (1);
+
if (ctx->max_reqs == 0)
goto out_cleanup;
- /* now link into global list. kludge. FIXME */
- write_lock(&mm->ioctx_list_lock);
- ctx->next = mm->ioctx_list;
- mm->ioctx_list = ctx;
- write_unlock(&mm->ioctx_list_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);
dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
__set_current_state(TASK_RUNNING);
return iocb->ki_user_data;
}
+EXPORT_SYMBOL(wait_on_sync_kiocb);
/* exit_aio: called when the last user of mm goes away. At this point,
* there is no way for any new requests to be submited or any of the
*/
void exit_aio(struct mm_struct *mm)
{
- struct kioctx *ctx = mm->ioctx_list;
- mm->ioctx_list = NULL;
- while (ctx) {
- struct kioctx *next = ctx->next;
- ctx->next = NULL;
+ struct kioctx *ctx;
+
+ while (!hlist_empty(&mm->ioctx_list)) {
+ ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
+ hlist_del_rcu(&ctx->list);
+
aio_cancel_all(ctx);
wait_for_all_aios(ctx);
atomic_read(&ctx->users), ctx->dead,
ctx->reqs_active);
put_ioctx(ctx);
- ctx = next;
- }
-}
-
-/* __put_ioctx
- * Called when the last user of an aio context has gone away,
- * and the struct needs to be freed.
- */
-void __put_ioctx(struct kioctx *ctx)
-{
- unsigned nr_events = ctx->max_reqs;
-
- BUG_ON(ctx->reqs_active);
-
- cancel_delayed_work(&ctx->wq);
- cancel_work_sync(&ctx->wq.work);
- aio_free_ring(ctx);
- mmdrop(ctx->mm);
- ctx->mm = NULL;
- pr_debug("__put_ioctx: freeing %p\n", ctx);
- kmem_cache_free(kioctx_cachep, ctx);
-
- if (nr_events) {
- spin_lock(&aio_nr_lock);
- BUG_ON(aio_nr - nr_events > aio_nr);
- aio_nr -= nr_events;
- spin_unlock(&aio_nr_lock);
}
}
req->private = NULL;
req->ki_iovec = NULL;
INIT_LIST_HEAD(&req->ki_run_list);
- req->ki_eventfd = ERR_PTR(-EINVAL);
+ req->ki_eventfd = NULL;
/* Check if the completion queue has enough free space to
* accept an event from this io.
{
assert_spin_locked(&ctx->ctx_lock);
- if (!IS_ERR(req->ki_eventfd))
- fput(req->ki_eventfd);
+ 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)
list_del(&req->ki_list);
spin_unlock_irq(&fput_lock);
- /* Complete the fput */
- __fput(req->ki_filp);
+ /* Complete the fput(s) */
+ if (req->ki_filp != NULL)
+ __fput(req->ki_filp);
/* Link the iocb into the context's free list */
spin_lock_irq(&ctx->ctx_lock);
*/
static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
{
- dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
- req, atomic_read(&req->ki_filp->f_count));
+ dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
+ req, atomic_long_read(&req->ki_filp->f_count));
assert_spin_locked(&ctx->ctx_lock);
- req->ki_users --;
+ req->ki_users--;
BUG_ON(req->ki_users < 0);
if (likely(req->ki_users))
return 0;
req->ki_cancel = NULL;
req->ki_retry = NULL;
- /* Must be done under the lock to serialise against cancellation.
- * Call this aio_fput as it duplicates fput via the fput_work.
+ /*
+ * Try to optimize the aio and eventfd file* puts, by avoiding to
+ * schedule work in case it is not __fput() time. In normal cases,
+ * we would not be holding the last reference to the file*, so
+ * this function will be executed w/out any aio kthread wakeup.
*/
- if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
+ if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) {
get_ioctx(ctx);
spin_lock(&fput_lock);
list_add(&req->ki_list, &fput_head);
spin_unlock(&fput_lock);
queue_work(aio_wq, &fput_work);
- } else
+ } else {
+ req->ki_filp = NULL;
really_put_req(ctx, req);
+ }
return 1;
}
spin_unlock_irq(&ctx->ctx_lock);
return ret;
}
+EXPORT_SYMBOL(aio_put_req);
-/* Lookup an ioctx id. ioctx_list is lockless for reads.
- * FIXME: this is O(n) and is only suitable for development.
- */
-struct kioctx *lookup_ioctx(unsigned long ctx_id)
+static struct kioctx *lookup_ioctx(unsigned long ctx_id)
{
- struct kioctx *ioctx;
- struct mm_struct *mm;
+ struct mm_struct *mm = current->mm;
+ struct kioctx *ctx, *ret = NULL;
+ struct hlist_node *n;
+
+ rcu_read_lock();
- mm = current->mm;
- read_lock(&mm->ioctx_list_lock);
- for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next)
- if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) {
- get_ioctx(ioctx);
+ hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
+ if (ctx->user_id == ctx_id && !ctx->dead) {
+ get_ioctx(ctx);
+ ret = ctx;
break;
}
- read_unlock(&mm->ioctx_list_lock);
-
- return ioctx;
-}
-
-/*
- * use_mm
- * Makes the calling kernel thread take on the specified
- * mm context.
- * Called by the retry thread execute retries within the
- * iocb issuer's mm context, so that copy_from/to_user
- * operations work seamlessly for aio.
- * (Note: this routine is intended to be called only
- * from a kernel thread context)
- */
-static void use_mm(struct mm_struct *mm)
-{
- struct mm_struct *active_mm;
- struct task_struct *tsk = current;
-
- task_lock(tsk);
- tsk->flags |= PF_BORROWED_MM;
- active_mm = tsk->active_mm;
- atomic_inc(&mm->mm_count);
- tsk->mm = mm;
- tsk->active_mm = mm;
- /*
- * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
- * it won't work. Update it accordingly if you change it here
- */
- switch_mm(active_mm, mm, tsk);
- task_unlock(tsk);
-
- mmdrop(active_mm);
-}
-
-/*
- * unuse_mm
- * Reverses the effect of use_mm, i.e. releases the
- * specified mm context which was earlier taken on
- * by the calling kernel thread
- * (Note: this routine is intended to be called only
- * from a kernel thread context)
- */
-static void unuse_mm(struct mm_struct *mm)
-{
- struct task_struct *tsk = current;
+ }
- task_lock(tsk);
- tsk->flags &= ~PF_BORROWED_MM;
- tsk->mm = NULL;
- /* active_mm is still 'mm' */
- enter_lazy_tlb(mm, tsk);
- task_unlock(tsk);
+ rcu_read_unlock();
+ return ret;
}
/*
*/
ret = retry(iocb);
- if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
- BUG_ON(!list_empty(&iocb->ki_wait.task_list));
+ if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED)
aio_complete(iocb, ret, 0);
- }
out:
spin_lock_irq(&ctx->ctx_lock);
unsigned long flags;
int run = 0;
- /* We're supposed to be the only path putting the iocb back on the run
- * list. If we find that the iocb is *back* on a wait queue already
- * than retry has happened before we could queue the iocb. This also
- * means that the retry could have completed and freed our iocb, no
- * good. */
- BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
-
spin_lock_irqsave(&ctx->ctx_lock, flags);
/* set this inside the lock so that we can't race with aio_run_iocb()
* testing it and putting the iocb on the run list under the lock */
/*
* kick_iocb:
* Called typically from a wait queue callback context
- * (aio_wake_function) to trigger a retry of the iocb.
+ * to trigger a retry of the iocb.
* The retry is usually executed by aio workqueue
* threads (See aio_kick_handler).
*/
return 1;
}
- /*
- * Check if the user asked us to deliver the result through an
- * eventfd. The eventfd_signal() function is safe to be called
- * from IRQ context.
- */
- if (!IS_ERR(iocb->ki_eventfd))
- eventfd_signal(iocb->ki_eventfd, 1);
-
info = &ctx->ring_info;
/* add a completion event to the ring buffer.
kunmap_atomic(ring, KM_IRQ1);
pr_debug("added to ring %p at [%lu]\n", iocb, tail);
+
+ /*
+ * Check if the user asked us to deliver the result through an
+ * eventfd. The eventfd_signal() function is safe to be called
+ * from IRQ context.
+ */
+ if (iocb->ki_eventfd != NULL)
+ eventfd_signal(iocb->ki_eventfd, 1);
+
put_rq:
/* everything turned out well, dispose of the aiocb. */
ret = __aio_put_req(ctx, iocb);
+ /*
+ * We have to order our ring_info tail store above and test
+ * of the wait list below outside the wait lock. This is
+ * like in wake_up_bit() where clearing a bit has to be
+ * ordered with the unlocked test.
+ */
+ smp_mb();
+
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
return ret;
}
+EXPORT_SYMBOL(aio_complete);
/* aio_read_evt
* Pull an event off of the ioctx's event ring. Returns the number of
static inline void init_timeout(struct aio_timeout *to)
{
- init_timer(&to->timer);
- to->timer.data = (unsigned long)to;
- to->timer.function = timeout_func;
+ setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
to->timed_out = 0;
to->p = current;
}
break;
if (min_nr <= i)
break;
- ret = 0;
+ if (unlikely(ctx->dead)) {
+ ret = -EINVAL;
+ break;
+ }
if (to.timed_out) /* Only check after read evt */
break;
/* Try to only show up in io wait if there are ops
if (timeout)
clear_timeout(&to);
out:
+ destroy_timer_on_stack(&to.timer);
return i ? i : ret;
}
static void io_destroy(struct kioctx *ioctx)
{
struct mm_struct *mm = current->mm;
- struct kioctx **tmp;
int was_dead;
/* delete the entry from the list is someone else hasn't already */
- write_lock(&mm->ioctx_list_lock);
+ spin_lock(&mm->ioctx_lock);
was_dead = ioctx->dead;
ioctx->dead = 1;
- for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx;
- tmp = &(*tmp)->next)
- ;
- if (*tmp)
- *tmp = ioctx->next;
- write_unlock(&mm->ioctx_list_lock);
+ hlist_del_rcu(&ioctx->list);
+ spin_unlock(&mm->ioctx_lock);
dprintk("aio_release(%p)\n", ioctx);
if (likely(!was_dead))
aio_cancel_all(ioctx);
wait_for_all_aios(ioctx);
+
+ /*
+ * Wake up any waiters. The setting of ctx->dead must be seen
+ * by other CPUs at this point. Right now, we rely on the
+ * locking done by the above calls to ensure this consistency.
+ */
+ wake_up(&ioctx->wait);
put_ioctx(ioctx); /* once for the lookup */
}
* pointer is passed for ctxp. Will fail with -ENOSYS if not
* implemented.
*/
-asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)
+SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
* implemented. May fail with -EFAULT if the context pointed to
* is invalid.
*/
-asmlinkage long sys_io_destroy(aio_context_t ctx)
+SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
{
struct kioctx *ioctx = lookup_ioctx(ctx);
if (likely(NULL != ioctx)) {
return 0;
}
-/*
- * aio_wake_function:
- * wait queue callback function for aio notification,
- * Simply triggers a retry of the operation via kick_iocb.
- *
- * This callback is specified in the wait queue entry in
- * a kiocb.
- *
- * Note:
- * This routine is executed with the wait queue lock held.
- * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
- * the ioctx lock inside the wait queue lock. This is safe
- * because this callback isn't used for wait queues which
- * are nested inside ioctx lock (i.e. ctx->wait)
- */
-static int aio_wake_function(wait_queue_t *wait, unsigned mode,
- int sync, void *key)
+static void aio_batch_add(struct address_space *mapping,
+ struct hlist_head *batch_hash)
{
- struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
+ struct aio_batch_entry *abe;
+ struct hlist_node *pos;
+ unsigned bucket;
+
+ bucket = hash_ptr(mapping, AIO_BATCH_HASH_BITS);
+ hlist_for_each_entry(abe, pos, &batch_hash[bucket], list) {
+ if (abe->mapping == mapping)
+ return;
+ }
- list_del_init(&wait->task_list);
- kick_iocb(iocb);
- return 1;
+ abe = mempool_alloc(abe_pool, GFP_KERNEL);
+ BUG_ON(!igrab(mapping->host));
+ abe->mapping = mapping;
+ hlist_add_head(&abe->list, &batch_hash[bucket]);
+ return;
}
-int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
- struct iocb *iocb)
+static void aio_batch_free(struct hlist_head *batch_hash)
+{
+ struct aio_batch_entry *abe;
+ struct hlist_node *pos, *n;
+ int i;
+
+ for (i = 0; i < AIO_BATCH_HASH_SIZE; i++) {
+ hlist_for_each_entry_safe(abe, pos, n, &batch_hash[i], list) {
+ blk_run_address_space(abe->mapping);
+ iput(abe->mapping->host);
+ hlist_del(&abe->list);
+ mempool_free(abe, abe_pool);
+ }
+ }
+}
+
+static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
+ struct iocb *iocb, struct hlist_head *batch_hash)
{
struct kiocb *req;
struct file *file;
* an eventfd() fd, and will be signaled for each completed
* event using the eventfd_signal() function.
*/
- req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
- if (unlikely(IS_ERR(req->ki_eventfd))) {
+ req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
+ if (IS_ERR(req->ki_eventfd)) {
ret = PTR_ERR(req->ki_eventfd);
+ req->ki_eventfd = NULL;
goto out_put_req;
}
}
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;
- init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
- INIT_LIST_HEAD(&req->ki_wait.task_list);
ret = aio_setup_iocb(req);
;
}
spin_unlock_irq(&ctx->ctx_lock);
+ if (req->ki_opcode == IOCB_CMD_PREAD ||
+ req->ki_opcode == IOCB_CMD_PREADV ||
+ req->ki_opcode == IOCB_CMD_PWRITE ||
+ req->ki_opcode == IOCB_CMD_PWRITEV)
+ aio_batch_add(file->f_mapping, batch_hash);
+
aio_put_req(req); /* drop extra ref to req */
return 0;
* are available to queue any iocbs. Will return 0 if nr is 0. Will
* fail with -ENOSYS if not implemented.
*/
-asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
- struct iocb __user * __user *iocbpp)
+SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
+ struct iocb __user * __user *, iocbpp)
{
struct kioctx *ctx;
long ret = 0;
int i;
+ struct hlist_head batch_hash[AIO_BATCH_HASH_SIZE] = { { 0, }, };
if (unlikely(nr < 0))
return -EINVAL;
break;
}
- ret = io_submit_one(ctx, user_iocb, &tmp);
+ ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash);
if (ret)
break;
}
+ aio_batch_free(batch_hash);
put_ioctx(ctx);
return i ? i : ret;
* invalid. May fail with -EAGAIN if the iocb specified was not
* cancelled. Will fail with -ENOSYS if not implemented.
*/
-asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
- struct io_event __user *result)
+SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
+ struct io_event __user *, result)
{
int (*cancel)(struct kiocb *iocb, struct io_event *res);
struct kioctx *ctx;
* will be updated if not NULL and the operation blocks. Will fail
* with -ENOSYS if not implemented.
*/
-asmlinkage long sys_io_getevents(aio_context_t ctx_id,
- long min_nr,
- long nr,
- struct io_event __user *events,
- struct timespec __user *timeout)
+SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
+ long, min_nr,
+ long, nr,
+ struct io_event __user *, events,
+ struct timespec __user *, timeout)
{
struct kioctx *ioctx = lookup_ioctx(ctx_id);
long ret = -EINVAL;
put_ioctx(ioctx);
}
+ asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
return ret;
}
-
-__initcall(aio_setup);
-
-EXPORT_SYMBOL(aio_complete);
-EXPORT_SYMBOL(aio_put_req);
-EXPORT_SYMBOL(wait_on_sync_kiocb);
Code Review / linux-2.6.git / blobdiff