X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Faio.c;h=02a2c9340573cf5946e0083187353d4517319844;hb=9c2693c9243b81802c6860570557165e874779a7;hp=6af92194062266d842adfd57cf8abff425bd6ec5;hpb=6cb2a21049b8990df4576c5fce4d48d0206c22d5;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/aio.c b/fs/aio.c index 6af9219..02a2c93 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -34,7 +35,6 @@ #include #include -#include #if DEBUG > 1 #define dprintk printk @@ -78,6 +78,7 @@ static int __init aio_setup(void) return 0; } +__initcall(aio_setup); static void aio_free_ring(struct kioctx *ctx) { @@ -191,6 +192,48 @@ static int aio_setup_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. */ @@ -198,6 +241,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) { struct mm_struct *mm; struct kioctx *ctx; + int did_sync = 0; /* Prevent overflows */ if ((nr_events > (0x10000000U / sizeof(struct io_event))) || @@ -230,21 +274,30 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) 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); @@ -328,6 +381,7 @@ ssize_t wait_on_sync_kiocb(struct kiocb *iocb) __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 @@ -338,11 +392,12 @@ ssize_t wait_on_sync_kiocb(struct kiocb *iocb) */ 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); @@ -357,33 +412,6 @@ void exit_aio(struct mm_struct *mm) 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); } } @@ -417,7 +445,7 @@ static struct kiocb *__aio_get_req(struct kioctx *ctx) 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. @@ -459,8 +487,8 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) { 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) @@ -482,8 +510,9 @@ static void aio_fput_routine(struct work_struct *data) 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); @@ -501,12 +530,12 @@ static void aio_fput_routine(struct work_struct *data) */ 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; @@ -514,17 +543,22 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) 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; } @@ -541,76 +575,26 @@ int aio_put_req(struct kiocb *req) 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; } /* @@ -936,14 +920,6 @@ int aio_complete(struct kiocb *iocb, long res, long res2) 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. @@ -992,6 +968,15 @@ int aio_complete(struct kiocb *iocb, long res, long res2) 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); @@ -1010,6 +995,7 @@ put_rq: 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 @@ -1069,9 +1055,7 @@ static void timeout_func(unsigned long data) 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; } @@ -1165,7 +1149,10 @@ retry: 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 @@ -1201,6 +1188,7 @@ retry: if (timeout) clear_timeout(&to); out: + destroy_timer_on_stack(&to.timer); return i ? i : ret; } @@ -1210,19 +1198,14 @@ out: 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)) @@ -1230,6 +1213,13 @@ static void io_destroy(struct kioctx *ioctx) 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 */ } @@ -1246,7 +1236,7 @@ static void io_destroy(struct kioctx *ioctx) * 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; @@ -1284,7 +1274,7 @@ out: * 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)) { @@ -1541,7 +1531,7 @@ static int aio_wake_function(wait_queue_t *wait, unsigned mode, return 1; } -int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, +static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, struct iocb *iocb) { struct kiocb *req; @@ -1581,9 +1571,10 @@ int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, * 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; } } @@ -1638,8 +1629,8 @@ out_put_req: * 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; @@ -1713,8 +1704,8 @@ static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, * 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; @@ -1775,11 +1766,11 @@ asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb, * 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; @@ -1790,11 +1781,6 @@ asmlinkage long sys_io_getevents(aio_context_t ctx_id, 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);