diff options
| -rw-r--r-- | fs/aio.c | 116 | ||||
| -rw-r--r-- | include/linux/aio.h | 1 |
2 files changed, 15 insertions, 102 deletions
@@ -510,108 +510,27 @@ void exit_aio(struct mm_struct *mm) * This prevents races between the aio code path referencing the * req (after submitting it) and aio_complete() freeing the req. */ -static struct kiocb *__aio_get_req(struct kioctx *ctx) +static inline struct kiocb *aio_get_req(struct kioctx *ctx) { - struct kiocb *req = NULL; + struct kiocb *req; + + if (atomic_read(&ctx->reqs_active) >= ctx->ring_info.nr) + return NULL; + + if (atomic_inc_return(&ctx->reqs_active) > ctx->ring_info.nr - 1) + goto out_put; req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); if (unlikely(!req)) - return NULL; + goto out_put; atomic_set(&req->ki_users, 2); req->ki_ctx = ctx; return req; -} - -/* - * struct kiocb's are allocated in batches to reduce the number of - * times the ctx lock is acquired and released. - */ -#define KIOCB_BATCH_SIZE 32L -struct kiocb_batch { - struct list_head head; - long count; /* number of requests left to allocate */ -}; - -static void kiocb_batch_init(struct kiocb_batch *batch, long total) -{ - INIT_LIST_HEAD(&batch->head); - batch->count = total; -} - -static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch) -{ - struct kiocb *req, *n; - - if (list_empty(&batch->head)) - return; - - spin_lock_irq(&ctx->ctx_lock); - list_for_each_entry_safe(req, n, &batch->head, ki_batch) { - list_del(&req->ki_batch); - kmem_cache_free(kiocb_cachep, req); - atomic_dec(&ctx->reqs_active); - } - spin_unlock_irq(&ctx->ctx_lock); -} - -/* - * Allocate a batch of kiocbs. This avoids taking and dropping the - * context lock a lot during setup. - */ -static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) -{ - unsigned short allocated, to_alloc; - long avail; - struct kiocb *req, *n; - - to_alloc = min(batch->count, KIOCB_BATCH_SIZE); - for (allocated = 0; allocated < to_alloc; allocated++) { - req = __aio_get_req(ctx); - if (!req) - /* allocation failed, go with what we've got */ - break; - list_add(&req->ki_batch, &batch->head); - } - - if (allocated == 0) - goto out; - - spin_lock_irq(&ctx->ctx_lock); - - avail = ctx->ring_info.nr - atomic_read(&ctx->reqs_active) - 1; - BUG_ON(avail < 0); - if (avail < allocated) { - /* Trim back the number of requests. */ - list_for_each_entry_safe(req, n, &batch->head, ki_batch) { - list_del(&req->ki_batch); - kmem_cache_free(kiocb_cachep, req); - if (--allocated <= avail) - break; - } - } - - batch->count -= allocated; - atomic_add(allocated, &ctx->reqs_active); - - spin_unlock_irq(&ctx->ctx_lock); - -out: - return allocated; -} - -static inline struct kiocb *aio_get_req(struct kioctx *ctx, - struct kiocb_batch *batch) -{ - struct kiocb *req; - - if (list_empty(&batch->head)) - if (kiocb_batch_refill(ctx, batch) == 0) - return NULL; - req = list_first_entry(&batch->head, struct kiocb, ki_batch); - list_del(&req->ki_batch); - return req; +out_put: + atomic_dec(&ctx->reqs_active); + return NULL; } static void kiocb_free(struct kiocb *req) @@ -1198,8 +1117,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) } static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, - struct iocb *iocb, struct kiocb_batch *batch, - bool compat) + struct iocb *iocb, bool compat) { struct kiocb *req; ssize_t ret; @@ -1220,7 +1138,7 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, return -EINVAL; } - req = aio_get_req(ctx, batch); /* returns with 2 references to req */ + req = aio_get_req(ctx); /* returns with 2 references to req */ if (unlikely(!req)) return -EAGAIN; @@ -1293,7 +1211,6 @@ long do_io_submit(aio_context_t ctx_id, long nr, long ret = 0; int i = 0; struct blk_plug plug; - struct kiocb_batch batch; if (unlikely(nr < 0)) return -EINVAL; @@ -1310,8 +1227,6 @@ long do_io_submit(aio_context_t ctx_id, long nr, return -EINVAL; } - kiocb_batch_init(&batch, nr); - blk_start_plug(&plug); /* @@ -1332,13 +1247,12 @@ long do_io_submit(aio_context_t ctx_id, long nr, break; } - ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat); + ret = io_submit_one(ctx, user_iocb, &tmp, compat); if (ret) break; } blk_finish_plug(&plug); - kiocb_batch_free(ctx, &batch); put_ioctx(ctx); return i ? i : ret; } diff --git a/include/linux/aio.h b/include/linux/aio.h index d2a00038ec77..f0a8481af99b 100644 --- a/include/linux/aio.h +++ b/include/linux/aio.h @@ -85,7 +85,6 @@ struct kiocb { struct list_head ki_list; /* the aio core uses this * for cancellation */ - struct list_head ki_batch; /* batch allocation */ /* * If the aio_resfd field of the userspace iocb is not zero, |