Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751408AbVKIVPr (ORCPT ); Wed, 9 Nov 2005 16:15:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751428AbVKIVPq (ORCPT ); Wed, 9 Nov 2005 16:15:46 -0500 Received: from tetsuo.zabbo.net ([207.173.201.20]:18562 "EHLO tetsuo.zabbo.net") by vger.kernel.org with ESMTP id S1751408AbVKIVPe (ORCPT ); Wed, 9 Nov 2005 16:15:34 -0500 From: Zach Brown To: linux-aio@kvack.org, linux-kernel@vger.kernel.org Cc: Benjamin LaHaise , Andrew Morton Message-Id: <20051109211808.25027.75305.sendpatchset@volauvent.pdx.zabbo.net> In-Reply-To: <20051109211758.25027.78199.sendpatchset@volauvent.pdx.zabbo.net> References: <20051109211758.25027.78199.sendpatchset@volauvent.pdx.zabbo.net> Subject: [PATCH 3/3] aio: make ctx ref debugging depend on DEBUG Date: Wed, 9 Nov 2005 13:15:16 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4428 Lines: 140 aio: make ctx ref debugging depend on DEBUG Formalize ctx refcount debugging by putting it in legible inline functions and making it conditional on DEBUG. In doing so a bug is also fixed where the decref debugging was testing the ref count after dropping its reference, opening a race with another thread that might free. Signed-off-by: Zach Brown --- fs/aio.c | 65 +++++++++++++++++++++++++++++----------------------- include/linux/aio.h | 4 --- 2 files changed, 37 insertions(+), 32 deletions(-) Index: 2.6.14-mm1-aio-cleanups/fs/aio.c =================================================================== --- 2.6.14-mm1-aio-cleanups.orig/fs/aio.c 2005-11-09 11:48:27.394115109 -0800 +++ 2.6.14-mm1-aio-cleanups/fs/aio.c 2005-11-09 11:52:30.663874807 -0800 @@ -37,8 +37,10 @@ #if DEBUG > 1 #define dprintk printk +#define AIO_DEBUG_BUG_ON BUG_ON #else #define dprintk(x...) do { ; } while (0) +#define AIO_DEBUG_BUG_ON(x...) do { ; } while (0) #endif /*------ sysctl variables----*/ @@ -171,6 +173,40 @@ return 0; } +static inline void get_ioctx(struct kioctx *ctx) +{ + AIO_DEBUG_BUG_ON(atomic_read(&ctx->users) <= 0); + atomic_inc(&ctx->users); +} + +static void __put_ioctx(struct kioctx *ctx) +{ + unsigned nr_events = ctx->max_reqs; + + BUG_ON(ctx->reqs_active); + + cancel_delayed_work(&ctx->wq); + flush_workqueue(aio_wq); + 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); + } +} + +static inline void put_ioctx(struct kioctx *ctx) +{ + AIO_DEBUG_BUG_ON(atomic_read(&ctx->users) == 0); + if (atomic_dec_and_test(&ctx->users)) + __put_ioctx(ctx); +} /* aio_ring_event: returns a pointer to the event at the given index from * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); @@ -255,7 +291,7 @@ return ctx; out_cleanup: - __put_ioctx(ctx); + put_ioctx(ctx); return ERR_PTR(-EAGAIN); out_freectx: @@ -360,33 +396,6 @@ } } -/* __put_ioctx - * Called when the last user of an aio context has gone away, - * and the struct needs to be freed. - */ -void fastcall __put_ioctx(struct kioctx *ctx) -{ - unsigned nr_events = ctx->max_reqs; - - if (unlikely(ctx->reqs_active)) - BUG(); - - cancel_delayed_work(&ctx->wq); - flush_workqueue(aio_wq); - 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); - } -} - /* aio_get_req * Allocate a slot for an aio request. Increments the users count * of the kioctx so that the kioctx stays around until all requests are Index: 2.6.14-mm1-aio-cleanups/include/linux/aio.h =================================================================== --- 2.6.14-mm1-aio-cleanups.orig/include/linux/aio.h 2005-11-09 11:48:22.848483645 -0800 +++ 2.6.14-mm1-aio-cleanups/include/linux/aio.h 2005-11-09 11:48:31.907756204 -0800 @@ -198,7 +198,6 @@ extern int FASTCALL(aio_put_req(struct kiocb *iocb)); extern void FASTCALL(kick_iocb(struct kiocb *iocb)); extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2)); -extern void FASTCALL(__put_ioctx(struct kioctx *ctx)); struct mm_struct; extern void FASTCALL(exit_aio(struct mm_struct *mm)); extern struct kioctx *lookup_ioctx(unsigned long ctx_id); @@ -210,9 +209,6 @@ int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, struct iocb *iocb)); -#define get_ioctx(kioctx) do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0) -#define put_ioctx(kioctx) do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0) - #define in_aio() !is_sync_wait(current->io_wait) /* may be used for debugging */ #define warn_if_async() \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/