From 3ffa3c0e3f6e62f67fc2346ca60161dfb030083d Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 24 Jun 2012 10:00:10 +0400 Subject: aio: now fput() is OK from interrupt context; get rid of manual delayed __fput() Signed-off-by: Al Viro --- fs/aio.c | 73 +++------------------------------------------------------------- 1 file changed, 3 insertions(+), 70 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 55c4c7656053..71f613cf4a85 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -56,13 +56,6 @@ static struct kmem_cache *kioctx_cachep; static struct workqueue_struct *aio_wq; -/* Used for rare fput completion. */ -static void aio_fput_routine(struct work_struct *); -static DECLARE_WORK(fput_work, aio_fput_routine); - -static DEFINE_SPINLOCK(fput_lock); -static LIST_HEAD(fput_head); - static void aio_kick_handler(struct work_struct *); static void aio_queue_work(struct kioctx *); @@ -479,7 +472,6 @@ static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) { unsigned short allocated, to_alloc; long avail; - bool called_fput = false; struct kiocb *req, *n; struct aio_ring *ring; @@ -495,28 +487,11 @@ static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) if (allocated == 0) goto out; -retry: spin_lock_irq(&ctx->ctx_lock); ring = kmap_atomic(ctx->ring_info.ring_pages[0]); avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active; BUG_ON(avail < 0); - if (avail == 0 && !called_fput) { - /* - * Handle a potential starvation case. It is possible that - * we hold the last reference on a struct file, causing us - * to delay the final fput to non-irq context. In this case, - * ctx->reqs_active is artificially high. Calling the fput - * routine here may free up a slot in the event completion - * ring, allowing this allocation to succeed. - */ - kunmap_atomic(ring); - spin_unlock_irq(&ctx->ctx_lock); - aio_fput_routine(NULL); - called_fput = true; - goto retry; - } - if (avail < allocated) { /* Trim back the number of requests. */ list_for_each_entry_safe(req, n, &batch->head, ki_batch) { @@ -570,36 +545,6 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) wake_up_all(&ctx->wait); } -static void aio_fput_routine(struct work_struct *data) -{ - spin_lock_irq(&fput_lock); - while (likely(!list_empty(&fput_head))) { - struct kiocb *req = list_kiocb(fput_head.next); - struct kioctx *ctx = req->ki_ctx; - - list_del(&req->ki_list); - spin_unlock_irq(&fput_lock); - - /* Complete the fput(s) */ - if (req->ki_filp != NULL) - fput(req->ki_filp); - - /* Link the iocb into the context's free list */ - rcu_read_lock(); - spin_lock_irq(&ctx->ctx_lock); - really_put_req(ctx, req); - /* - * at that point ctx might've been killed, but actual - * freeing is RCU'd - */ - spin_unlock_irq(&ctx->ctx_lock); - rcu_read_unlock(); - - spin_lock_irq(&fput_lock); - } - spin_unlock_irq(&fput_lock); -} - /* __aio_put_req * Returns true if this put was the last user of the request. */ @@ -618,21 +563,9 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) req->ki_cancel = NULL; req->ki_retry = NULL; - /* - * Try to optimize the aio and eventfd file* puts, by avoiding to - * schedule work in case it is not final 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(!fput_atomic(req->ki_filp))) { - spin_lock(&fput_lock); - list_add(&req->ki_list, &fput_head); - spin_unlock(&fput_lock); - schedule_work(&fput_work); - } else { - req->ki_filp = NULL; - really_put_req(ctx, req); - } + fput(req->ki_filp); + req->ki_filp = NULL; + really_put_req(ctx, req); return 1; } -- cgit v1.2.3-70-g09d2