[v1,2/3] net/ring: fix eth_dev device pointer on allocation
Checks
Commit Message
When a net_ring device is allocated, its device pointer is not set
before calling rte_eth_dev_probing_finish, which is incorrect.
The following:
commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
commit: a6992e961050 ("net/ring: set ethernet device field")
already attempted to fix this issue in 17.08, which was fine at the
time. Adding the hook rte_eth_dev_probing_finish() however created this
bug, as the eth_dev exposed when this hook is executed is expected to be
complete.
Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
write the pointer properly in do_eth_dev_ring_create().
Cc: stable@dpdk.org
Fixes: fbe90cdd776c ("ethdev: add probing finish function")
Cc: ferruh.yigit@intel.com
Cc: thomas@monjalon.net
Signed-off-by: Gaetan Rivet <grive@u256.net>
---
drivers/net/ring/rte_eth_ring.c | 36 ++++++++++++++++++++++++++-------
1 file changed, 29 insertions(+), 7 deletions(-)
Comments
On 5/5/2020 8:10 PM, Gaetan Rivet wrote:
> When a net_ring device is allocated, its device pointer is not set
> before calling rte_eth_dev_probing_finish, which is incorrect.
>
> The following:
> commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
> commit: a6992e961050 ("net/ring: set ethernet device field")
>
> already attempted to fix this issue in 17.08, which was fine at the
> time. Adding the hook rte_eth_dev_probing_finish() however created this
> bug, as the eth_dev exposed when this hook is executed is expected to be
> complete.
>
> Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
> write the pointer properly in do_eth_dev_ring_create().
>
> Cc: stable@dpdk.org
> Fixes: fbe90cdd776c ("ethdev: add probing finish function")
> Cc: ferruh.yigit@intel.com
> Cc: thomas@monjalon.net
> Signed-off-by: Gaetan Rivet <grive@u256.net>
<...>
> @@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
> data->kdrv = RTE_KDRV_NONE;
> data->numa_node = numa_node;
>
> - /* finally assign rx and tx ops */
> + /* assign rx and tx ops */
> eth_dev->rx_pkt_burst = eth_ring_rx;
> eth_dev->tx_pkt_burst = eth_ring_tx;
>
> + /* finally set the rte_device pointer in eth_dev. */
> + eth_dev->device = ring_device_from_name(name);
> + if (eth_dev->device == NULL) {
> + rte_errno = ENODEV;
> + goto error;
> + }
> +
> rte_eth_dev_probing_finish(eth_dev);
> *eth_dev_p = eth_dev;
Why not move the 'rte_eth_dev_probing_finish()' to the 'rte_pmd_ring_probe()',
below where 'eth_dev->device' set?
On 06/05/20 12:48 +0100, Ferruh Yigit wrote:
> On 5/5/2020 8:10 PM, Gaetan Rivet wrote:
> > When a net_ring device is allocated, its device pointer is not set
> > before calling rte_eth_dev_probing_finish, which is incorrect.
> >
> > The following:
> > commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
> > commit: a6992e961050 ("net/ring: set ethernet device field")
> >
> > already attempted to fix this issue in 17.08, which was fine at the
> > time. Adding the hook rte_eth_dev_probing_finish() however created this
> > bug, as the eth_dev exposed when this hook is executed is expected to be
> > complete.
> >
> > Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
> > write the pointer properly in do_eth_dev_ring_create().
> >
> > Cc: stable@dpdk.org
> > Fixes: fbe90cdd776c ("ethdev: add probing finish function")
> > Cc: ferruh.yigit@intel.com
> > Cc: thomas@monjalon.net
> > Signed-off-by: Gaetan Rivet <grive@u256.net>
>
> <...>
>
> > @@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
> > data->kdrv = RTE_KDRV_NONE;
> > data->numa_node = numa_node;
> >
> > - /* finally assign rx and tx ops */
> > + /* assign rx and tx ops */
> > eth_dev->rx_pkt_burst = eth_ring_rx;
> > eth_dev->tx_pkt_burst = eth_ring_tx;
> >
> > + /* finally set the rte_device pointer in eth_dev. */
> > + eth_dev->device = ring_device_from_name(name);
> > + if (eth_dev->device == NULL) {
> > + rte_errno = ENODEV;
> > + goto error;
> > + }
> > +
> > rte_eth_dev_probing_finish(eth_dev);
> > *eth_dev_p = eth_dev;
>
> Why not move the 'rte_eth_dev_probing_finish()' to the 'rte_pmd_ring_probe()',
> below where 'eth_dev->device' set?
Hi Ferruh,
Sure it would work. The reason I did it this way is two-fold:
* I disliked having two places where eth_dev->device was conditionally
set. It makes it harder to read rte_pmd_ring_probe.
* I was actually thinking, doing this patch, that we should modify
rte_eth_dev_allocate() to take an rte_device as parameter, as all
eth_dev are meant to be backed by an rte_device. Keeping this in
mind, I meant to move writing the pointer closer to the
rte_eth_dev_allocate() call.
But you are right that it is needlessly verbose, using
vdev_bus->find_device() to do this stuff. I'm ok with changing it as you
described if you prefer.
On 5/6/2020 1:33 PM, Gaëtan Rivet wrote:
> On 06/05/20 12:48 +0100, Ferruh Yigit wrote:
>> On 5/5/2020 8:10 PM, Gaetan Rivet wrote:
>>> When a net_ring device is allocated, its device pointer is not set
>>> before calling rte_eth_dev_probing_finish, which is incorrect.
>>>
>>> The following:
>>> commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
>>> commit: a6992e961050 ("net/ring: set ethernet device field")
>>>
>>> already attempted to fix this issue in 17.08, which was fine at the
>>> time. Adding the hook rte_eth_dev_probing_finish() however created this
>>> bug, as the eth_dev exposed when this hook is executed is expected to be
>>> complete.
>>>
>>> Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
>>> write the pointer properly in do_eth_dev_ring_create().
>>>
>>> Cc: stable@dpdk.org
>>> Fixes: fbe90cdd776c ("ethdev: add probing finish function")
>>> Cc: ferruh.yigit@intel.com
>>> Cc: thomas@monjalon.net
>>> Signed-off-by: Gaetan Rivet <grive@u256.net>
>>
>> <...>
>>
>>> @@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
>>> data->kdrv = RTE_KDRV_NONE;
>>> data->numa_node = numa_node;
>>>
>>> - /* finally assign rx and tx ops */
>>> + /* assign rx and tx ops */
>>> eth_dev->rx_pkt_burst = eth_ring_rx;
>>> eth_dev->tx_pkt_burst = eth_ring_tx;
>>>
>>> + /* finally set the rte_device pointer in eth_dev. */
>>> + eth_dev->device = ring_device_from_name(name);
>>> + if (eth_dev->device == NULL) {
>>> + rte_errno = ENODEV;
>>> + goto error;
>>> + }
>>> +
>>> rte_eth_dev_probing_finish(eth_dev);
>>> *eth_dev_p = eth_dev;
>>
>> Why not move the 'rte_eth_dev_probing_finish()' to the 'rte_pmd_ring_probe()',
>> below where 'eth_dev->device' set?
>
> Hi Ferruh,
>
> Sure it would work. The reason I did it this way is two-fold:
>
> * I disliked having two places where eth_dev->device was conditionally
> set. It makes it harder to read rte_pmd_ring_probe.
Agree, what about using a 'goto' to have the assignment and
'rte_eth_dev_probing_finish()' in a single place?
But check seems needed since creation may failed at that stage, if you think
better check can be done on 'ret' instead of 'eth_dev'...
>
> * I was actually thinking, doing this patch, that we should modify
> rte_eth_dev_allocate() to take an rte_device as parameter, as all
> eth_dev are meant to be backed by an rte_device. Keeping this in
> mind, I meant to move writing the pointer closer to the
> rte_eth_dev_allocate() call.
That is a bigger change, may affect many (if not all) PMDs, so I think this can
be considered when that change is available.
And although that change may fix the issues that 'eth_dev->device' is not set,
which we had a few times before, not sure it worth to change all PMDs and ethdev
API directly couple with rte_device, instead of PMD being the glue. Can be
discussed more on its own patch.
>
> But you are right that it is needlessly verbose, using
> vdev_bus->find_device() to do this stuff. I'm ok with changing it as you
> described if you prefer.
>
That was the concern, that is too much code to take a value which is already
available a few level up the stack.
On 06/05/20 14:43 +0100, Ferruh Yigit wrote:
> On 5/6/2020 1:33 PM, Gaëtan Rivet wrote:
> > On 06/05/20 12:48 +0100, Ferruh Yigit wrote:
> >> On 5/5/2020 8:10 PM, Gaetan Rivet wrote:
> >>> When a net_ring device is allocated, its device pointer is not set
> >>> before calling rte_eth_dev_probing_finish, which is incorrect.
> >>>
> >>> The following:
> >>> commit: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
> >>> commit: a6992e961050 ("net/ring: set ethernet device field")
> >>>
> >>> already attempted to fix this issue in 17.08, which was fine at the
> >>> time. Adding the hook rte_eth_dev_probing_finish() however created this
> >>> bug, as the eth_dev exposed when this hook is executed is expected to be
> >>> complete.
> >>>
> >>> Remove the prior attempts to fix the issue in rte_pmd_ring_probe() and
> >>> write the pointer properly in do_eth_dev_ring_create().
> >>>
> >>> Cc: stable@dpdk.org
> >>> Fixes: fbe90cdd776c ("ethdev: add probing finish function")
> >>> Cc: ferruh.yigit@intel.com
> >>> Cc: thomas@monjalon.net
> >>> Signed-off-by: Gaetan Rivet <grive@u256.net>
> >>
> >> <...>
> >>
> >>> @@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
> >>> data->kdrv = RTE_KDRV_NONE;
> >>> data->numa_node = numa_node;
> >>>
> >>> - /* finally assign rx and tx ops */
> >>> + /* assign rx and tx ops */
> >>> eth_dev->rx_pkt_burst = eth_ring_rx;
> >>> eth_dev->tx_pkt_burst = eth_ring_tx;
> >>>
> >>> + /* finally set the rte_device pointer in eth_dev. */
> >>> + eth_dev->device = ring_device_from_name(name);
> >>> + if (eth_dev->device == NULL) {
> >>> + rte_errno = ENODEV;
> >>> + goto error;
> >>> + }
> >>> +
> >>> rte_eth_dev_probing_finish(eth_dev);
> >>> *eth_dev_p = eth_dev;
> >>
> >> Why not move the 'rte_eth_dev_probing_finish()' to the 'rte_pmd_ring_probe()',
> >> below where 'eth_dev->device' set?
> >
> > Hi Ferruh,
> >
> > Sure it would work. The reason I did it this way is two-fold:
> >
> > * I disliked having two places where eth_dev->device was conditionally
> > set. It makes it harder to read rte_pmd_ring_probe.
>
> Agree, what about using a 'goto' to have the assignment and
> 'rte_eth_dev_probing_finish()' in a single place?
> But check seems needed since creation may failed at that stage, if you think
> better check can be done on 'ret' instead of 'eth_dev'...
>
> >
> > * I was actually thinking, doing this patch, that we should modify
> > rte_eth_dev_allocate() to take an rte_device as parameter, as all
> > eth_dev are meant to be backed by an rte_device. Keeping this in
> > mind, I meant to move writing the pointer closer to the
> > rte_eth_dev_allocate() call.
>
> That is a bigger change, may affect many (if not all) PMDs, so I think this can
> be considered when that change is available.
>
> And although that change may fix the issues that 'eth_dev->device' is not set,
> which we had a few times before, not sure it worth to change all PMDs and ethdev
> API directly couple with rte_device, instead of PMD being the glue. Can be
> discussed more on its own patch.
>
> >
> > But you are right that it is needlessly verbose, using
> > vdev_bus->find_device() to do this stuff. I'm ok with changing it as you
> > described if you prefer.
> >
>
> That was the concern, that is too much code to take a value which is already
> available a few level up the stack.
Ok, future-proofing is a bad habit so let's not do it.
I'm not a fan of the goto for the 'happy path' though. Another simple
way would be to bring the vdev pointer with me as we go down the stack.
I will send a v2 shortly, if it's too ugly to move the pointer down I'll
use the goto, or if you tell me you'd prefer it.
@@ -244,6 +244,26 @@ static const struct eth_dev_ops ops = {
.mac_addr_add = eth_mac_addr_add,
};
+static int
+dev_name_cmp(const struct rte_device *dev, const void *_name)
+{
+ const char *name = _name;
+
+ return strcmp(dev->name, name);
+}
+
+static struct rte_device *
+ring_device_from_name(const char *name)
+{
+ struct rte_bus *vdev_bus;
+
+ vdev_bus = rte_bus_find_by_name("vdev");
+ if (vdev_bus == NULL)
+ return NULL;
+
+ return vdev_bus->find_device(NULL, dev_name_cmp, name);
+}
+
static int
do_eth_dev_ring_create(const char *name,
struct rte_ring * const rx_queues[],
@@ -294,6 +314,7 @@ do_eth_dev_ring_create(const char *name,
* - store queue data in internals,
* - store numa_node info in eth_dev_data
* - point eth_dev_data to internals
+ * - store EAL device in eth_dev,
* - and point eth_dev structure to new eth_dev_data structure
*/
@@ -325,10 +346,17 @@ do_eth_dev_ring_create(const char *name,
data->kdrv = RTE_KDRV_NONE;
data->numa_node = numa_node;
- /* finally assign rx and tx ops */
+ /* assign rx and tx ops */
eth_dev->rx_pkt_burst = eth_ring_rx;
eth_dev->tx_pkt_burst = eth_ring_tx;
+ /* finally set the rte_device pointer in eth_dev. */
+ eth_dev->device = ring_device_from_name(name);
+ if (eth_dev->device == NULL) {
+ rte_errno = ENODEV;
+ goto error;
+ }
+
rte_eth_dev_probing_finish(eth_dev);
*eth_dev_p = eth_dev;
@@ -584,9 +612,6 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
DEV_ATTACH, ð_dev);
}
- if (eth_dev)
- eth_dev->device = &dev->device;
-
return ret;
}
@@ -644,9 +669,6 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
}
}
- if (eth_dev)
- eth_dev->device = &dev->device;
-
out_free:
rte_kvargs_free(kvlist);
rte_free(info);