Pull block fixes from Jens Axboe:

 - Fix for a regression with setting up loop on a file system
   without ->write_iter()

 - Fix for an nvme sysfs regression

* tag 'block-6.15-20250522' of git://git.kernel.dk/linux:
  nvme: avoid creating multipath sysfs group under namespace path devices
  loop: don't require ->write_iter for writable files in loop_configure

Commit 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin
io-policy") introduced the creation of the multipath sysfs group under
the NVMe head gendisk device node. However, it also inadvertently added
the same sysfs group under each namespace path device which head node
refers to and that is incorrect.

The multipath sysfs group should only be exposed through the namespace
head gendisk node. This is sufficient, as the head device already
provides symbolic links to the individual namespace paths it manages.

This patch fixes the issue by preventing the creation of the multipath
sysfs group under namespace path devices, ensuring it only appears under
the head disk node.

Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy")
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
      - fixes for atomic writes (Alan Adamson)
      - fixes for polled CQs in nvmet-epf (Damien Le Moal)
      - fix for polled CQs in nvme-pci (Keith Busch)
      - fix compile on odd configs that need to be forced to inline
        (Kees Cook)
      - one more quirk (Ilya Guterman)

 - Fix for missing allocation of an integrity buffer for some cases

 - Fix for a regression with ublk command cancelation

* tag 'block-6.15-20250515' of git://git.kernel.dk/linux:
  ublk: fix dead loop when canceling io command
  nvme-pci: add NVME_QUIRK_NO_DEEPEST_PS quirk for SOLIDIGM P44 Pro
  nvme: all namespaces in a subsystem must adhere to a common atomic write size
  nvme: multipath: enable BLK_FEAT_ATOMIC_WRITES for multipathing
  nvmet: pci-epf: remove NVMET_PCI_EPF_Q_IS_SQ
  nvmet: pci-epf: improve debug message
  nvmet: pci-epf: cleanup nvmet_pci_epf_raise_irq()
  nvmet: pci-epf: do not fall back to using INTX if not supported
  nvmet: pci-epf: clear completion queue IRQ flag on delete
  nvme-pci: acquire cq_poll_lock in nvme_poll_irqdisable
  nvme-pci: make nvme_pci_npages_prp() __always_inline
  block: always allocate integrity buffer when required

This commit adds the NVME_QUIRK_NO_DEEPEST_PS quirk for device
[126f:2262], which belongs to device SOLIDIGM P44 Pro SSDPFKKW020X7

The device frequently have trouble exiting the deepest power state (5),
resulting in the entire disk being unresponsive.

Verified by setting nvme_core.default_ps_max_latency_us=10000 and
observing the expected behavior.

Signed-off-by: Ilya Guterman <amfernusus@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The first namespace configured in a subsystem sets the subsystem's
atomic write size based on its AWUPF or NAWUPF. Subsequent namespaces
must have an atomic write size (per their AWUPF or NAWUPF) less than or
equal to the subsystem's atomic write size, or their probing will be
rejected.

Signed-off-by: Alan Adamson <alan.adamson@oracle.com>
[hch: fold in review comments from John Garry]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>

A change to QEMU resulted in all nvme controllers (single and
multi-controller subsystems) to have its CMIC.MCTRS bit set which
indicates the subsystem supports multiple controllers and it is possible
a namespace can be shared between those multiple controllers in a
multipath configuration.

When a namespace of a CMIC.MCTRS enabled subsystem is allocated, a
multipath node is created.  The queue limits for this node are inherited
from the namespace being allocated. When inheriting queue limits, the
features being inherited need to be specified. The atomic write feature
(BLK_FEAT_ATOMIC_WRITES) was not specified so the atomic queue limits
were not inherited by the multipath disk node which resulted in the sysfs
atomic write attributes being zeroed. The fix is to include
BLK_FEAT_ATOMIC_WRITES in the list of features to be inherited.

Signed-off-by: Alan Adamson <alan.adamson@oracle.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The flag NVMET_PCI_EPF_Q_IS_SQ is set but never used. Remove it.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Improve the debug message of nvmet_pci_epf_create_cq() to indicate if a
completion queue IRQ is disabled.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

There is no point in taking the controller irq_lock and calling
nvmet_pci_epf_should_raise_irq() for a completion queue which does not
have IRQ enabled (NVMET_PCI_EPF_Q_IRQ_ENABLED flag is not set).
Move the test for the NVMET_PCI_EPF_Q_IRQ_ENABLED flag out of
nvmet_pci_epf_should_raise_irq() to the top of nvmet_pci_epf_raise_irq()
to return early when no IRQ should be raised.

Also, use dev_err_ratelimited() to avoid a message storm under load when
raising IRQs is failing.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Some endpoint PCIe controllers do not support raising legacy INTX
interrupts. This support is indicated by the intx_capable field of
struct pci_epc_features. Modify nvmet_pci_epf_raise_irq() to not
automatically fallback to trying raising an INTX interrupt after an MSI
or MSI-X error if the controller does not support INTX.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>