[PATCH] io_uring: remove io_remove_personalities()

[PATCH] io_uring: remove io_remove_personalities()

[Yejune Deng]

The function io_remove_personalities() is very similar to
io_unregister_personality(),but the latter has a more reasonable
return value.

Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
---
 fs/io_uring.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b749578..000ea9a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8608,7 +8608,7 @@ static int io_uring_fasync(int fd, struct file *file, int on)
 	return fasync_helper(fd, file, on, &ctx->cq_fasync);
 }
 
-static int io_remove_personalities(int id, void *p, void *data)
+static int io_unregister_personality(int id, void *p, void *data)
 {
 	struct io_ring_ctx *ctx = data;
 	struct io_identity *iod;
@@ -8618,8 +8618,10 @@ static int io_remove_personalities(int id, void *p, void *data)
 		put_cred(iod->creds);
 		if (refcount_dec_and_test(&iod->count))
 			kfree(iod);
+		return 0;
 	}
-	return 0;
+
+	return -EINVAL;
 }
 
 static void io_ring_exit_work(struct work_struct *work)
@@ -8657,7 +8659,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
 
 	/* if we failed setting up the ctx, we might not have any rings */
 	io_iopoll_try_reap_events(ctx);
-	idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
+	idr_for_each(&ctx->personality_idr, io_unregister_personality, ctx);
 
 	/*
 	 * Do this upfront, so we won't have a grace period where the ring
@@ -9679,21 +9681,6 @@ static int io_register_personality(struct io_ring_ctx *ctx)
 	return ret;
 }
 
-static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
-{
-	struct io_identity *iod;
-
-	iod = idr_remove(&ctx->personality_idr, id);
-	if (iod) {
-		put_cred(iod->creds);
-		if (refcount_dec_and_test(&iod->count))
-			kfree(iod);
-		return 0;
-	}
-
-	return -EINVAL;
-}
-
 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
 				    unsigned int nr_args)
 {
@@ -9906,7 +9893,7 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 		ret = -EINVAL;
 		if (arg)
 			break;
-		ret = io_unregister_personality(ctx, nr_args);
+		ret = io_unregister_personality(nr_args, NULL, ctx);
 		break;
 	case IORING_REGISTER_ENABLE_RINGS:
 		ret = -EINVAL;
-- 
1.9.1

Re: [PATCH] io_uring: remove io_remove_personalities()

[Stefano Garzarella]

On Wed, Dec 23, 2020 at 11:27:05AM +0800, Yejune Deng wrote:
>The function io_remove_personalities() is very similar to
>io_unregister_personality(),but the latter has a more reasonable
>return value.
>
>Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
>---
> fs/io_uring.c | 25 ++++++-------------------
> 1 file changed, 6 insertions(+), 19 deletions(-)

The patch LGTM, maybe as an alternative you can leave 
io_remove_personality() with the interface needed by idr_for_each() and 
implement io_unregister_personality() calling io_remove_personality() 
with the right parameters.

Just an idea, but I'm also fine with this patch, so:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
>diff --git a/fs/io_uring.c b/fs/io_uring.c
>index b749578..000ea9a 100644
>--- a/fs/io_uring.c
>+++ b/fs/io_uring.c
>@@ -8608,7 +8608,7 @@ static int io_uring_fasync(int fd, struct file *file, int on)
> 	return fasync_helper(fd, file, on, &ctx->cq_fasync);
> }
>
>-static int io_remove_personalities(int id, void *p, void *data)
>+static int io_unregister_personality(int id, void *p, void *data)
> {
> 	struct io_ring_ctx *ctx = data;
> 	struct io_identity *iod;
>@@ -8618,8 +8618,10 @@ static int io_remove_personalities(int id, void *p, void *data)
> 		put_cred(iod->creds);
> 		if (refcount_dec_and_test(&iod->count))
> 			kfree(iod);
>+		return 0;
> 	}
>-	return 0;
>+
>+	return -EINVAL;
> }
>
> static void io_ring_exit_work(struct work_struct *work)
>@@ -8657,7 +8659,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
>
> 	/* if we failed setting up the ctx, we might not have any rings */
> 	io_iopoll_try_reap_events(ctx);
>-	idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
>+	idr_for_each(&ctx->personality_idr, io_unregister_personality, ctx);
>
> 	/*
> 	 * Do this upfront, so we won't have a grace period where the ring
>@@ -9679,21 +9681,6 @@ static int io_register_personality(struct io_ring_ctx *ctx)
> 	return ret;
> }
>
>-static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
>-{
>-	struct io_identity *iod;
>-
>-	iod = idr_remove(&ctx->personality_idr, id);
>-	if (iod) {
>-		put_cred(iod->creds);
>-		if (refcount_dec_and_test(&iod->count))
>-			kfree(iod);
>-		return 0;
>-	}
>-
>-	return -EINVAL;
>-}
>-
> static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
> 				    unsigned int nr_args)
> {
>@@ -9906,7 +9893,7 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
> 		ret = -EINVAL;
> 		if (arg)
> 			break;
>-		ret = io_unregister_personality(ctx, nr_args);
>+		ret = io_unregister_personality(nr_args, NULL, ctx);
> 		break;
> 	case IORING_REGISTER_ENABLE_RINGS:
> 		ret = -EINVAL;
>-- 
>1.9.1
>

Re: [PATCH] io_uring: remove io_remove_personalities()

[Pavel Begunkov]

On 23/12/2020 10:36, Stefano Garzarella wrote:
> On Wed, Dec 23, 2020 at 11:27:05AM +0800, Yejune Deng wrote:
>> The function io_remove_personalities() is very similar to
>> io_unregister_personality(),but the latter has a more reasonable
>> return value.
>>
>> Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
>> ---
>> fs/io_uring.c | 25 ++++++-------------------
>> 1 file changed, 6 insertions(+), 19 deletions(-)
> 
> The patch LGTM, maybe as an alternative you can leave io_remove_personality() with the interface needed by idr_for_each() and implement io_unregister_personality() calling io_remove_personality() with the right parameters.

Right, don't replace sane types with void * just because.
Leave well-typed io_unregister_personality() and call it from
io_remove_personalities().


Also
 * idr_for_each() - Iterate through all stored pointers.
 ...
 * If @fn returns anything other than %0, the iteration stops and that
 * value is returned from this function.

For io_remove_personality() iod==NULL should not happen because
it's under for_each and synchronised, but leave the return value be 

io_remove_personality(void *, ...)
{
	struct io_ring_ctx *ctx = data;

	io_unregister_personality(ctx, id);
	return 0;
}

-- 
Pavel Begunkov

Re: [PATCH] io_uring: remove io_remove_personalities()

[Yejune Deng]

OK，I will adopt it and resubmit.

On Wed, Dec 23, 2020 at 8:45 PM Pavel Begunkov <asml.silence@gmail.com> wrote:
>
> On 23/12/2020 10:36, Stefano Garzarella wrote:
> > On Wed, Dec 23, 2020 at 11:27:05AM +0800, Yejune Deng wrote:
> >> The function io_remove_personalities() is very similar to
> >> io_unregister_personality(),but the latter has a more reasonable
> >> return value.
> >>
> >> Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
> >> ---
> >> fs/io_uring.c | 25 ++++++-------------------
> >> 1 file changed, 6 insertions(+), 19 deletions(-)
> >
> > The patch LGTM, maybe as an alternative you can leave io_remove_personality() with the interface needed by idr_for_each() and implement io_unregister_personality() calling io_remove_personality() with the right parameters.
>
> Right, don't replace sane types with void * just because.
> Leave well-typed io_unregister_personality() and call it from
> io_remove_personalities().
>
>
> Also
>  * idr_for_each() - Iterate through all stored pointers.
>  ...
>  * If @fn returns anything other than %0, the iteration stops and that
>  * value is returned from this function.
>
> For io_remove_personality() iod==NULL should not happen because
> it's under for_each and synchronised, but leave the return value be
>
> io_remove_personality(void *, ...)
> {
>         struct io_ring_ctx *ctx = data;
>
>         io_unregister_personality(ctx, id);
>         return 0;
> }
>
> --
> Pavel Begunkov