[PATCH v5 1/3] aio_ring_remap: kill the bogus ctx->dead check

From: Oleg Nesterov
Date: Fri Jun 19 2015 - 14:20:15 EST


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.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
---
fs/aio.c | 9 +++------
1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 480440f..893d300 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -325,14 +325,11 @@ 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;
+ struct kioctx *ctx = table->table[i];

- 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;
- }
+ ctx->user_id = ctx->mmap_base = vma->vm_start;
+ res = 0;
break;
}
}
--
1.5.5.1

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