Re: [RFC PATCH 2/8] PCI/IOV: Create virtfn buses up front in sriov_add_vfs()

[sashiko-bot@kernel.org]

> virtfn_add_bus() is find-then-create and therefore assumes external
> serialization. Create every virtfn bus before adding any VF, taking the
> bus-create path out of the per-VF loop so a later commit can run the
> per-VF adds concurrently against a stable bus set. Bus numbers are
> already fixed before the loop, since pci_iov_set_numvfs() has latched
> offset and stride.
> 
> The cleanup pass must remove only buses this enable created, because
> virtfn_remove_bus() checks that a bus is empty rather than who created
> it, so virtfn_add_bus() now reports whether it created the bus and
> sriov_add_vfs() records that per VF id in a bitmap. Return early for
> num_vfs == 0: kvcalloc(0, ...) returns ZERO_SIZE_PTR and a later commit
> dereferences buses[0] unconditionally.
> 
> Several ids can share one bus number; only the creating id's bit is set.
> 
> Assisted-by: LLM
> Signed-off-by: Pavol Sakac <sakacpav@amazon.de>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260911-vfopt-s1-v1-0-693271dc0226@amazon.de?part=2