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From: Jiri Pirko <jiri@resnulli.us>
To: Parav Pandit <parav@mellanox.com>
Cc: alex.williamson@redhat.com, davem@davemloft.net,
	kvm@vger.kernel.org, netdev@vger.kernel.org, saeedm@mellanox.com,
	kwankhede@nvidia.com, leon@kernel.org, cohuck@redhat.com,
	jiri@mellanox.com, linux-rdma@vger.kernel.org
Subject: Re: [PATCH net-next 07/19] vfio/mdev: Introduce sha1 based mdev alias
Date: Fri, 8 Nov 2019 12:04:56 +0100
Message-ID: <20191108110456.GH6990@nanopsycho> (raw)
In-Reply-To: <20191107160834.21087-7-parav@mellanox.com>

Thu, Nov 07, 2019 at 05:08:22PM CET, parav@mellanox.com wrote:
>Some vendor drivers want an identifier for an mdev device that is
>shorter than the UUID, due to length restrictions in the consumers of
>that identifier.
>
>Add a callback that allows a vendor driver to request an alias of a
>specified length to be generated for an mdev device. If generated,
>that alias is checked for collisions.
>
>It is an optional attribute.
>mdev alias is generated using sha1 from the mdev name.
>
>Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
>Signed-off-by: Parav Pandit <parav@mellanox.com>
>---
> drivers/vfio/mdev/mdev_core.c    | 123 ++++++++++++++++++++++++++++++-
> drivers/vfio/mdev/mdev_private.h |   5 +-
> drivers/vfio/mdev/mdev_sysfs.c   |  13 ++--
> include/linux/mdev.h             |   4 +
> 4 files changed, 135 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>index b558d4cfd082..3bdff0469607 100644
>--- a/drivers/vfio/mdev/mdev_core.c
>+++ b/drivers/vfio/mdev/mdev_core.c
>@@ -10,9 +10,11 @@

[...]


>-int mdev_device_create(struct kobject *kobj,
>-		       struct device *dev, const guid_t *uuid)
>+static const char *
>+generate_alias(const char *uuid, unsigned int max_alias_len)
>+{
>+	struct shash_desc *hash_desc;
>+	unsigned int digest_size;
>+	unsigned char *digest;
>+	unsigned int alias_len;
>+	char *alias;
>+	int ret;
>+
>+	/*
>+	 * Align to multiple of 2 as bin2hex will generate
>+	 * even number of bytes.
>+	 */
>+	alias_len = roundup(max_alias_len, 2);

This is odd, see below.


>+	alias = kzalloc(alias_len + 1, GFP_KERNEL);
>+	if (!alias)
>+		return ERR_PTR(-ENOMEM);
>+
>+	/* Allocate and init descriptor */
>+	hash_desc = kvzalloc(sizeof(*hash_desc) +
>+			     crypto_shash_descsize(alias_hash),
>+			     GFP_KERNEL);
>+	if (!hash_desc) {
>+		ret = -ENOMEM;
>+		goto desc_err;
>+	}
>+
>+	hash_desc->tfm = alias_hash;
>+
>+	digest_size = crypto_shash_digestsize(alias_hash);
>+
>+	digest = kzalloc(digest_size, GFP_KERNEL);
>+	if (!digest) {
>+		ret = -ENOMEM;
>+		goto digest_err;
>+	}
>+	ret = crypto_shash_init(hash_desc);
>+	if (ret)
>+		goto hash_err;
>+
>+	ret = crypto_shash_update(hash_desc, uuid, UUID_STRING_LEN);
>+	if (ret)
>+		goto hash_err;
>+
>+	ret = crypto_shash_final(hash_desc, digest);
>+	if (ret)
>+		goto hash_err;
>+
>+	bin2hex(alias, digest, min_t(unsigned int, digest_size, alias_len / 2));
>+	/*
>+	 * When alias length is odd, zero out an additional last byte
>+	 * that bin2hex has copied.
>+	 */
>+	if (max_alias_len % 2)
>+		alias[max_alias_len] = 0;
>+
>+	kfree(digest);
>+	kvfree(hash_desc);
>+	return alias;
>+
>+hash_err:
>+	kfree(digest);
>+digest_err:
>+	kvfree(hash_desc);
>+desc_err:
>+	kfree(alias);
>+	return ERR_PTR(ret);
>+}
>+
>+int mdev_device_create(struct kobject *kobj, struct device *dev,
>+		       const char *uuid_str, const guid_t *uuid)
> {
> 	int ret;
> 	struct mdev_device *mdev, *tmp;
> 	struct mdev_parent *parent;
> 	struct mdev_type *type = to_mdev_type(kobj);
>+	const char *alias = NULL;
> 
> 	parent = mdev_get_parent(type->parent);
> 	if (!parent)
> 		return -EINVAL;
> 
>+	if (parent->ops->get_alias_length) {
>+		unsigned int alias_len;
>+
>+		alias_len = parent->ops->get_alias_length();
>+		if (alias_len) {

I think this should be with WARN_ON. Driver should not never return such
0 and if it does, it's a bug.

Also I think this check should be extended by checking value is multiple
of 2. Then you can avoid the roundup() above. No need to allow even len.


>+			alias = generate_alias(uuid_str, alias_len);
>+			if (IS_ERR(alias)) {
>+				ret = PTR_ERR(alias);
>+				goto alias_fail;
>+			}
>+		}
>+	}
> 	mutex_lock(&mdev_list_lock);
> 
> 	/* Check for duplicate */


[...]

>diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
>index 7570c7602ab4..43afe0e80b76 100644
>--- a/drivers/vfio/mdev/mdev_sysfs.c
>+++ b/drivers/vfio/mdev/mdev_sysfs.c
>@@ -63,15 +63,18 @@ static ssize_t create_store(struct kobject *kobj, struct device *dev,
> 		return -ENOMEM;
> 
> 	ret = guid_parse(str, &uuid);
>-	kfree(str);
> 	if (ret)
>-		return ret;
>+		goto err;
> 
>-	ret = mdev_device_create(kobj, dev, &uuid);
>+	ret = mdev_device_create(kobj, dev, str, &uuid);

Why to pass the same thing twice? Move the guid_parse() call to the
beginning of mdev_device_create() function.


> 	if (ret)
>-		return ret;
>+		goto err;
> 
>-	return count;
>+	ret = count;
>+
>+err:
>+	kfree(str);
>+	return ret;
> }
> 
> MDEV_TYPE_ATTR_WO(create);

[...]

  reply index

Thread overview: 132+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 16:04 [PATCH net-next 00/19] Mellanox, mlx5 sub function support Parav Pandit
2019-11-07 16:08 ` [PATCH net-next 01/19] net/mlx5: E-switch, Move devlink port close to eswitch port Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 02/19] net/mlx5: E-Switch, Add SF vport, vport-rep support Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 03/19] net/mlx5: Introduce SF table framework Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 04/19] net/mlx5: Introduce SF life cycle APIs to allocate/free Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 05/19] net/mlx5: E-Switch, Enable/disable SF's vport during SF life cycle Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 06/19] net/mlx5: Add support for mediated devices in switchdev mode Parav Pandit
2019-11-08 10:32     ` Jiri Pirko
2019-11-08 16:03       ` Parav Pandit
2019-11-08 16:22         ` Jiri Pirko
2019-11-08 16:29           ` Parav Pandit
2019-11-08 18:01             ` Jiri Pirko
2019-11-08 18:04             ` Jiri Pirko
2019-11-08 18:21               ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 07/19] vfio/mdev: Introduce sha1 based mdev alias Parav Pandit
2019-11-08 11:04     ` Jiri Pirko [this message]
2019-11-08 15:59       ` Parav Pandit
2019-11-08 16:28         ` Jiri Pirko
2019-11-08 11:10     ` Cornelia Huck
2019-11-08 16:03       ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 08/19] vfio/mdev: Make mdev alias unique among all mdevs Parav Pandit
2019-11-08 10:49     ` Jiri Pirko
2019-11-08 15:13       ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 09/19] vfio/mdev: Expose mdev alias in sysfs tree Parav Pandit
2019-11-08 13:22     ` Jiri Pirko
2019-11-08 18:03       ` Alex Williamson
2019-11-08 18:16         ` Jiri Pirko
2019-11-07 16:08   ` [PATCH net-next 10/19] vfio/mdev: Introduce an API mdev_alias Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 11/19] vfio/mdev: Improvise mdev life cycle and parent removal scheme Parav Pandit
2019-11-08 13:01     ` Cornelia Huck
2019-11-08 16:12       ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 12/19] devlink: Introduce mdev port flavour Parav Pandit
2019-11-07 20:38     ` Jakub Kicinski
2019-11-07 21:03       ` Parav Pandit
2019-11-08  1:17         ` Jakub Kicinski
2019-11-08  1:44           ` Parav Pandit
2019-11-08  2:20             ` Jakub Kicinski
2019-11-08  2:31               ` Parav Pandit
2019-11-08  9:46                 ` Jiri Pirko
2019-11-08 15:45                   ` Parav Pandit
2019-11-08 16:31                     ` Jiri Pirko
2019-11-08 16:43                       ` Parav Pandit
2019-11-08 18:11                         ` Jiri Pirko
2019-11-08 18:23                           ` Parav Pandit
2019-11-08 18:34                             ` Jiri Pirko
2019-11-08 18:56                               ` Parav Pandit
2019-11-08  9:30               ` Jiri Pirko
2019-11-08 15:41                 ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 13/19] net/mlx5: Register SF devlink port Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 14/19] net/mlx5: Share irqs between SFs and parent PCI device Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 15/19] net/mlx5: Add load/unload routines for SF driver binding Parav Pandit
2019-11-08  9:48     ` Jiri Pirko
2019-11-08 11:13       ` Jiri Pirko
2019-11-07 16:08   ` [PATCH net-next 16/19] net/mlx5: Implement dma ops and params for mediated device Parav Pandit
2019-11-07 20:42     ` Jakub Kicinski
2019-11-07 21:30       ` Parav Pandit
2019-11-08  1:16         ` Jakub Kicinski
2019-11-08  6:37     ` Christoph Hellwig
2019-11-08 15:29       ` Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 17/19] net/mlx5: Add mdev driver to bind to mdev devices Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 18/19] Documentation: net: mlx5: Add mdev usage documentation Parav Pandit
2019-11-07 16:08   ` [PATCH net-next 19/19] mtty: Optionally support mtty alias Parav Pandit
2019-11-08  6:26     ` Leon Romanovsky
2019-11-08 10:45     ` Jiri Pirko
2019-11-08 15:08       ` Parav Pandit
2019-11-08 15:15         ` Jiri Pirko
2019-11-08 13:46     ` Cornelia Huck
2019-11-08 15:10       ` Parav Pandit
2019-11-08 15:28         ` Cornelia Huck
2019-11-08 15:30           ` Parav Pandit
2019-11-08 17:54             ` Alex Williamson
2019-11-08  9:51   ` [PATCH net-next 01/19] net/mlx5: E-switch, Move devlink port close to eswitch port Jiri Pirko
2019-11-08 15:50     ` Parav Pandit
2019-11-07 17:03 ` [PATCH net-next 00/19] Mellanox, mlx5 sub function support Leon Romanovsky
2019-11-07 20:10   ` Parav Pandit
2019-11-08  6:20     ` Leon Romanovsky
2019-11-08 15:01       ` Parav Pandit
2019-11-07 20:32 ` Jakub Kicinski
2019-11-07 20:52   ` Parav Pandit
2019-11-08  1:16     ` Jakub Kicinski
2019-11-08  1:49       ` Parav Pandit
2019-11-08  2:12         ` Jakub Kicinski
2019-11-08 12:12   ` Jiri Pirko
2019-11-08 14:40     ` Jason Gunthorpe
2019-11-08 15:40       ` Parav Pandit
2019-11-08 19:12         ` Jakub Kicinski
2019-11-08 20:12           ` Jason Gunthorpe
2019-11-08 20:20             ` Parav Pandit
2019-11-08 20:32               ` Jason Gunthorpe
2019-11-08 20:52                 ` gregkh
2019-11-08 20:34             ` Alex Williamson
2019-11-08 21:05               ` Jason Gunthorpe
2019-11-08 21:19                 ` gregkh
2019-11-08 21:52                 ` Alex Williamson
2019-11-08 22:48                   ` Parav Pandit
2019-11-09  0:57                     ` Jason Gunthorpe
2019-11-09 17:41                       ` Jakub Kicinski
2019-11-10 19:04                         ` Jason Gunthorpe
2019-11-10 19:48                       ` Parav Pandit
2019-11-11 14:17                         ` Jiri Pirko
2019-11-11 14:58                           ` Parav Pandit
2019-11-11 15:06                             ` Jiri Pirko
2019-11-19  4:51                               ` Parav Pandit
2019-11-09  0:12                   ` Jason Gunthorpe
2019-11-09  0:45                     ` Parav Pandit
2019-11-11  2:19                 ` Jason Wang
2019-11-08 21:45             ` Jakub Kicinski
2019-11-09  0:44               ` Jason Gunthorpe
2019-11-09  8:46                 ` gregkh
2019-11-09 11:18                   ` Jiri Pirko
2019-11-09 17:28                     ` Jakub Kicinski
2019-11-10  9:16                     ` gregkh
2019-11-09 17:27                 ` Jakub Kicinski
2019-11-10  9:18                   ` gregkh
2019-11-11  3:46                     ` Jakub Kicinski
2019-11-11  5:18                       ` Parav Pandit
2019-11-11 13:30                       ` Jiri Pirko
2019-11-11 14:14                         ` gregkh
2019-11-11 14:37                           ` Jiri Pirko
2019-11-10 19:37                   ` Jason Gunthorpe
2019-11-11  3:57                     ` Jakub Kicinski
2019-11-08 16:06     ` Parav Pandit
2019-11-08 19:06     ` Jakub Kicinski
2019-11-08 19:34       ` Parav Pandit
2019-11-08 19:48         ` Jakub Kicinski
2019-11-08 19:41       ` Jiri Pirko
2019-11-08 20:40         ` Parav Pandit
2019-11-08 21:21         ` Jakub Kicinski
2019-11-08 21:39           ` Jiri Pirko
2019-11-08 21:51             ` Jakub Kicinski
2019-11-08 22:21               ` Jiri Pirko
2019-11-07 23:57 ` David Miller

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