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Subject[PATCH 06/32] aio: simplify KIOCB_KEY handling
Date
No need to pass the key field to lookup_iocb to compare it with KIOCB_KEY,
as we can do that right after retrieving it from userspace. Also move the
KIOCB_KEY definition to aio.c as it is an internal value not used by any
other place in the kernel.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/aio.c | 14 +++++++-------
include/linux/aio.h | 2 --
2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index f3eae5d5771b..2e0bc04f7920 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -46,6 +46,8 @@

#include "internal.h"

+#define KIOCB_KEY 0
+
#define AIO_RING_MAGIC 0xa10a10a1
#define AIO_RING_COMPAT_FEATURES 1
#define AIO_RING_INCOMPAT_FEATURES 0
@@ -1812,15 +1814,12 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
* Finds a given iocb for cancellation.
*/
static struct aio_kiocb *
-lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key)
+lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb)
{
struct aio_kiocb *kiocb;

assert_spin_locked(&ctx->ctx_lock);

- if (key != KIOCB_KEY)
- return NULL;
-
/* TODO: use a hash or array, this sucks. */
list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
if (kiocb->ki_user_iocb == iocb)
@@ -1847,9 +1846,10 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
u32 key;
int ret;

- ret = get_user(key, &iocb->aio_key);
- if (unlikely(ret))
+ if (unlikely(get_user(key, &iocb->aio_key)))
return -EFAULT;
+ if (unlikely(key != KIOCB_KEY))
+ return -EINVAL;

ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx))
@@ -1857,7 +1857,7 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,

spin_lock_irq(&ctx->ctx_lock);

- kiocb = lookup_kiocb(ctx, iocb, key);
+ kiocb = lookup_kiocb(ctx, iocb);
if (kiocb)
ret = kiocb_cancel(kiocb);
else
diff --git a/include/linux/aio.h b/include/linux/aio.h
index 9d8aabecfe2d..b83e68dd006f 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -8,8 +8,6 @@ struct kioctx;
struct kiocb;
struct mm_struct;

-#define KIOCB_KEY 0
-
typedef int (kiocb_cancel_fn)(struct kiocb *);

/* prototypes */
--
2.17.0
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