From: Jiri Pirko <jiri@resnulli.us>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Jacob Keller <jacob.e.keller@intel.com>,
netdev@vger.kernel.org, Jiri Pirko <jiri@mellanox.com>
Subject: Re: [PATCH 06/10] devlink: convert snapshot id getter to return an error
Date: Wed, 25 Mar 2020 20:13:56 +0100 [thread overview]
Message-ID: <20200325191356.GF11304@nanopsycho.orion> (raw)
In-Reply-To: <20200325110425.6fdf6cb3@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Wed, Mar 25, 2020 at 07:04:25PM CET, kuba@kernel.org wrote:
>On Tue, 24 Mar 2020 15:34:41 -0700 Jacob Keller wrote:
>> diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
>> index f7621ccb7b88..f9420b77e5fd 100644
>> --- a/drivers/net/netdevsim/dev.c
>> +++ b/drivers/net/netdevsim/dev.c
>> @@ -45,8 +45,7 @@ static ssize_t nsim_dev_take_snapshot_write(struct file *file,
>> {
>> struct nsim_dev *nsim_dev = file->private_data;
>> void *dummy_data;
>> - int err;
>> - u32 id;
>> + int err, id;
>>
>> dummy_data = kmalloc(NSIM_DEV_DUMMY_REGION_SIZE, GFP_KERNEL);
>> if (!dummy_data)
>> @@ -55,6 +54,10 @@ static ssize_t nsim_dev_take_snapshot_write(struct file *file,
>> get_random_bytes(dummy_data, NSIM_DEV_DUMMY_REGION_SIZE);
>>
>> id = devlink_region_snapshot_id_get(priv_to_devlink(nsim_dev));
>> + if (id < 0) {
>> + pr_err("Failed to get snapshot id\n");
>> + return id;
>> + }
>> err = devlink_region_snapshot_create(nsim_dev->dummy_region,
>> dummy_data, id);
>> if (err) {
>
>Hmm... next patch introduces some ref counting on the ID AFAICT,
>should there be some form of snapshot_id_put(), once the driver is
>done creating the regions it wants?
>
>First what if driver wants to create two snapshots with the same ID but
>user space manages to delete the first one before second one is created.
>
>Second what if create fails, won't the snapshot ID just stay in XA with
>count of 0 forever?
Yeah, that seems like a race condition this is introducing.
next prev parent reply other threads:[~2020-03-25 19:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 22:34 [PATCH 00/10] implement DEVLINK_CMD_REGION_NEW Jacob Keller
2020-03-24 22:34 ` [PATCH 01/10] devlink: prepare to support region operations Jacob Keller
2020-03-24 22:34 ` [PATCH 02/10] devlink: convert snapshot destructor callback to region op Jacob Keller
2020-03-24 22:34 ` [PATCH 03/10] devlink: trivial: fix tab in function documentation Jacob Keller
2020-03-24 22:34 ` [PATCH 04/10] devlink: add function to take snapshot while locked Jacob Keller
2020-03-25 17:56 ` Jakub Kicinski
2020-03-24 22:34 ` [PATCH 05/10] devlink: extract snapshot id allocation to helper function Jacob Keller
2020-03-25 14:08 ` Jiri Pirko
2020-03-24 22:34 ` [PATCH 06/10] devlink: convert snapshot id getter to return an error Jacob Keller
2020-03-25 18:04 ` Jakub Kicinski
2020-03-25 19:13 ` Jiri Pirko [this message]
2020-03-26 1:33 ` Jacob Keller
2020-03-24 22:34 ` [PATCH] devlink: track snapshot id usage count using an xarray Jacob Keller
2020-03-25 16:08 ` Jiri Pirko
2020-03-26 1:16 ` Jacob Keller
2020-03-26 1:43 ` Jacob Keller
2020-03-24 22:34 ` [PATCH 08/10] devlink: implement DEVLINK_CMD_REGION_NEW Jacob Keller
2020-03-25 16:46 ` Jiri Pirko
2020-03-25 17:18 ` Jakub Kicinski
2020-03-25 17:20 ` Jiri Pirko
2020-03-25 17:46 ` Jakub Kicinski
2020-03-25 18:41 ` Jiri Pirko
2020-03-26 1:30 ` Jacob Keller
2020-03-24 22:34 ` [PATCH 09/10] netdevsim: support taking immediate snapshot via devlink Jacob Keller
2020-03-25 16:50 ` Jiri Pirko
2020-03-24 22:34 ` [PATCH 10/10] ice: add a devlink region for dumping NVM contents Jacob Keller
2020-03-25 17:18 ` Jiri Pirko
2020-03-25 13:49 ` [PATCH 00/10] implement DEVLINK_CMD_REGION_NEW Jiri Pirko
2020-03-25 13:50 ` Jiri Pirko
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