Messages in this thread Patch in this message | | | Date | Wed, 17 Jun 2015 01:04:26 +0200 | From | Oleg Nesterov <> | Subject | [PATCH 1/3] aio_ring_remap: turn the ctx->dead check into WARN_ON() |
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atomic_read(&ctx->dead) in aio_ring_remap() looks confusing. kill_ioctx() sets ctx->dead and removes ctx from ->ioctx_table "atomically" under mm->ioctx_lock, so aio_ring_remap() can never see a dead ctx.
If we really want this check, we should put it under WARN_ON() and it should not depend on aio_ring_file == file.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- fs/aio.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c index 480440f..0693333 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -325,14 +325,14 @@ static int aio_ring_remap(struct file *file, struct vm_area_struct *vma) rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); for (i = 0; i < table->nr; i++) { - struct kioctx *ctx; - - ctx = table->table[i]; - if (ctx && ctx->aio_ring_file == file) { - if (!atomic_read(&ctx->dead)) { - ctx->user_id = ctx->mmap_base = vma->vm_start; - res = 0; - } + struct kioctx *ctx = table->table[i]; + + if (!ctx || WARN_ON(atomic_read(&ctx->dead))) + continue; + + if (ctx->aio_ring_file == file) { + ctx->user_id = ctx->mmap_base = vma->vm_start; + res = 0; break; } } -- 1.5.5.1
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