[PATCH] nvme: don't create block device for inactive namespace

[Heinrich Schuchardt]

Am 18. Juni 2021 07:47:37 MESZ schrieb Bin Meng <bmeng.cn at gmail.com>:
>+ML
>
>On Fri, Jun 18, 2021 at 1:47 PM Bin Meng <bmeng.cn at gmail.com> wrote:
>>
>> Hi Heinrich,
>>
>> On Thu, Jun 17, 2021 at 7:04 PM Heinrich Schuchardt
><xypron.glpk at gmx.de> wrote:
>> >
>> > QEMU returns the highest supported namespace number NN as 255. This
>does
>> > not imply that there are 255 active namespaces.
>> >
>> > If a namespace is not active, the namespace identify command
>returns a zero
>> > filled data structure. We can use field NSZE (namespace size) to
>decide if
>> > a block device should be created.
>>
>> Thanks for the fix. Apparently QEMU has changed its behavior of
>namespaces.
>>
>> >
>> > Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> > ---
>> >  drivers/nvme/nvme-uclass.c | 30 +++++++++++++++++++++++++++++-
>> >  1 file changed, 29 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/nvme/nvme-uclass.c
>b/drivers/nvme/nvme-uclass.c
>> > index 277e31e1f3..f7861f5287 100644
>> > --- a/drivers/nvme/nvme-uclass.c
>> > +++ b/drivers/nvme/nvme-uclass.c
>> > @@ -4,22 +4,50 @@
>> >   * Copyright (C) 2017 Bin Meng <bmeng.cn at gmail.com>
>> >   */
>> >
>> > +#define LOG_CATEGORY UCLASS_NVME
>> > +
>> >  #include <common.h>
>> >  #include <blk.h>
>> >  #include <errno.h>
>> >  #include <dm.h>
>> >  #include <dm/device.h>
>> > +#include <log.h>
>> > +#include <memalign.h>
>> > +#include <nvme.h>
>> >  #include "nvme.h"
>> >
>> > +/**
>> > + * nvme_probe_namespace() - check if namespace is active
>> > + *
>> > + * @dev:       NVMe controller device
>> > + * @ns_id:     namespace ID
>> > + * Return:     0 if namespace exists, -ve on error
>> > + */
>> > +static int nvme_probe_namespace(struct nvme_dev *dev, unsigned int
>ns_id)
>> > +{
>> > +       ALLOC_CACHE_ALIGN_BUFFER(char, buf_ns, sizeof(struct
>nvme_id_ns));
>> > +       struct nvme_id_ns *id = (struct nvme_id_ns *)buf_ns;
>> > +
>> > +       if (nvme_identify(dev, ns_id, 0, (dma_addr_t)(long)id))
>> > +               return -EIO;
>> > +       log_debug("ns_id %u, nsze %llu\n", ns_id, id->nsze);
>> > +       if (!id->nsze)
>> > +               return -ENOENT;
>> > +       return 0;
>> > +}
>> > +
>> >  static int nvme_uclass_post_probe(struct udevice *udev)
>> >  {
>> >         char name[20];
>> >         struct udevice *ns_udev;
>> > -       int i, ret;
>> > +       unsigned int i;
>> > +       int ret;
>> >         struct nvme_dev *ndev = dev_get_priv(udev);
>> >
>> >         /* Create a blk device for each namespace */
>> >         for (i = 0; i < ndev->nn; i++) {
>>
>> I suggest we assign correct number of namespaces in
>> nvme_get_info_from_identify() instead.
>>

The active mamespaces could be 23, 78, 167. In what way would it help here to know there are three of them?

It might make sense to eliminate the offset of one.

Best regards

Heinrich


>> > +               if (nvme_probe_namespace(ndev, i + 1))
>> > +                       continue;
>> >                 /*
>> >                  * Encode the namespace id to the device name so
>that
>> >                  * we can extract it when doing the probe.
>>
>> Regards,
>> Bin