The ACS specification does not allow a non-NCQ command to be issued while
an NCQ command is outstanding.

Commit 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
introduced a feature where a deferred non-NCQ command gets issued from a
workqueue. The design stores a single non-NCQ command per port.

However, when using Port Multipliers (PMPs), specifically PMPs that
support FIS-Based Switching (FBS), non-NCQ and NCQ commands can be mixed
on the same port, just not for the same link, see e.g. ata_std_qc_defer()
which is, and always has operated on a per-link basis.

Therefore, move the deferred_qc from struct ata_port to struct ata_link.
This way, when using a PMP with FBS, we will not needlessly defer commands
to all other links, just because one link issued a non-NCQ command while
having an NCQ command outstanding. Only commands for that specific link
will be deferred. This is in line with how PMPs with FBS worked before
commit 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation").

Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
Tested-by: Tommy Kelly <linux@tkel.ly>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

When using Port Multipliers (PMPs) with Command-Based Switching (CBS), you
can only issue commands to one link at a time. For PMPs with CBS, there is
already code to handle commands being sent to different links in
sata_pmp_qc_defer_cmd_switch() using ap->excl_link. sata_sil24 also makes
use of ap->excl_link.

A user on the list reported that commit 0ea84089dbf6 ("ata: libata-scsi:
avoid Non-NCQ command starvation") broke PMPs with CBS. The commit
introduced code that stores a deferred qc in ap->deferred_qc, to later be
issued via a workqueue. It turns out that this change is incompatible with
the existing ap->excl_link handling used by PMPs with CBS.

Thus, modify sata_pmp_qc_defer_cmd_switch() and sil24_qc_defer() to return
ATA_DEFER_LINK_EXCL, and make sure that the deferred QC handling via
workqueue is not used for this return value.

This way, PMPs with CBS will work once again. Note that the starvation
referenced in commit 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ
command starvation") can only happen on libsas ports, and libsas does not
support Port Multipliers, thus there is no harm of reverting back to the
previous way of deferring commands for PMPs with CBS.

Non-libsas ports connected to anything but a PMP with CBS (e.g. a normal
drive or a PMP with FBS) will continue using the deferred workqueue, since
it does result in lower completion latencies for non-NCQ commands, even
though the workqueue is not strictly needed to avoid starvation for
non-libsas ports.

If we want to modify the scope of the workqueue issuing to also handle
PMPs with CBS, then we should ensure that we can save both NCQ and non-NCQ
commands in ap->deferred_qc, while also removing the existing PMP CBS
handling using ap->excl_link, such that we don't duplicate features.

While at it, also add a comment explaining how the ap->excl_link mechanism
works.

Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
Tested-by: Tommy Kelly <linux@tkel.ly>
Reported-by: Tommy Kelly <linux@tkel.ly>
Closes: https://lore.kernel.org/linux-ide/ce09cc21-a8e9-4845-b205-35411e22fba9@tkel.ly/
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

The deferred QC feature was meant to handle mixed NCQ and non-NCQ commands,
i.e. for return value ATA_DEFER_LINK.

ATA_DEFER_PORT is returned by PATA drivers, but also certain SATA drivers
like sata_mv and sata_sil24 that uses ap->excl_link to workaround hardware
bugs in these HBAs. Regardless of the reason, using the deferred QC feature
for ATA_DEFER_PORT is always wrong, and will break the ap->excl_link usage
of the SATA drivers that rely on that feature.

Modify ata_scsi_qc_issue() to only use the deferred QC feature when mixing
NCQ and non-NCQ commands, i.e. ATA_DEFER_LINK.

Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
Tested-by: Tommy Kelly <linux@tkel.ly>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Improve readability of ata_scsi_qc_issue().

No functional changes.

Tested-by: Tommy Kelly <linux@tkel.ly>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Driver core expects devices to be dynamically allocated and will, for
example, complain loudly when no release function has been provided.

Use root_device_register() to allocate and register the root device
instead of open coding using a static device.

Note that this also fixes a reference leak in the unlikely event that
device_register() ever fails.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Pull ata updates from Niklas Cassel:

 - Misc code cleanups related to tag checking and tag command completion
   (Damien)

 - Remove Baikal bt1-ahci DT binding since the upstreaming for this SoC
   is not going to be finalized (Andy)

 - Only call the libata port error handler from the SCSI error handler
   if there were command timeouts or if EH was scheduled for the port
   (Damien)

 - Refactor ata_scsiop_maint_in() to more clearly show that there is
   only one service action implemented for the MAINTENANCE IN command
   (me)

 - Clean up the handling of sysfs attributes exposed by libata (Heiner)

 - Let libahci_platform use a flexible array member for platform PHYs to
   avoid multiple allocations (Rosen)

 - Do not retry reset if the device has been removed/hot-unplugged
   (Igor)

 - Add missing newlines to error prints in pata_arasan_cf driver (Haoyu)

 - Use the correct SCSI host byte when completing deferred ATA
   PASS-THROUGH commands, to avoid the SCSI mid-layer from failing the
   commands instead of requeuing (Igor)

* tag 'ata-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
  ata: libata-scsi: fix requeue of deferred ATA PASS-THROUGH commands
  ata: pata_arasan_cf: fix missing newline in dev_err() messages
  ata: libata-transport: remove static variable ata_scsi_transport_template
  ata: libata-transport: split struct ata_internal
  ata: libata-transport: use static struct ata_transport_internal to simplify match functions
  ata: libata-transport: inline ata_attach|release_transport
  ata: libata-transport: instantiate struct ata_internal statically
  ata: libata-eh: Do not retry reset if the device is gone
  ata: libahci_platform: use flex array for platform PHYs
  ata: libata-transport: remove redundant dynamic sysfs attributes
  ata: libata-scsi: refactor ata_scsiop_maint_in()
  ata: libata-eh: avoid unnecessary calls to ata_scsi_port_error_handler()
  ata: ahci-dwc: Remove not-going-to-be-supported code for Baikal SoC
  ata: libata-scsi: rename and improve ata_qc_done()
  ata: libata-scsi: make ata_scsi_simulate() static
  ata: libata-scsi: simplify ata_scsi_requeue_deferred_qc()
  ata: libata-sata: simplify ata_sas_queuecmd()
  ata: libata-core: improve tag checks in ata_qc_issue()

Commit 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
introduced ata_scsi_requeue_deferred_qc() to handle commands deferred
during resets or NCQ failures. This deferral logic completed commands
with DID_SOFT_ERROR to trigger a retry in the SCSI mid-layer.

However, DID_SOFT_ERROR is subject to scsi_cmd_retry_allowed() checks.
ATA PASS-THROUGH commands sent via SG_IO ioctl have scmd->allowed set
to zero. This causes the mid-layer to fail the command immediately
instead of retrying, even though the command was never actually issued
to the hardware.

Switch to DID_REQUEUE to ensure these commands are inserted back into
the request queue regardless of retry limits.

Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

The JMicron JMB585 (and JMB582) SATA controllers advertise 64-bit DMA
support via the S64A bit in the AHCI CAP register, but their 64-bit DMA
implementation is defective. Under sustained I/O, DMA transfers targeting
addresses above 4GB silently corrupt data -- writes land at incorrect
memory addresses with no errors logged.

The failure pattern is similar to the ASMedia ASM1061
(commit 20730e9b2778 ("ahci: add 43-bit DMA address quirk for ASMedia
ASM1061 controllers")), which also falsely advertised full 64-bit DMA
support. However, the JMB585 requires a stricter 32-bit DMA mask rather
than 43-bit, as corruption occurs with any address above 4GB.

On the Minisforum N5 Pro specifically, the combination of the JMB585's
broken 64-bit DMA with the AMD Family 1Ah (Strix Point) IOMMU causes
silent data corruption that is only detectable via checksumming
filesystems (BTRFS/ZFS scrub). The corruption occurs when 32-bit IOVA
space is exhausted and the kernel transparently switches to 64-bit DMA
addresses.

Add device-specific PCI ID entries for the JMB582 (0x0582) and JMB585
(0x0585) before the generic JMicron class match, using a new board type
that combines AHCI_HFLAG_IGN_IRQ_IF_ERR (preserving existing behavior)
with AHCI_HFLAG_32BIT_ONLY to force 32-bit DMA masks.

Signed-off-by: Arthur Husband <artmoty@gmail.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Add missing trailing newlines to dev_err() messages in pata_arasan_cf.c.

This keeps the error output as properly terminated log lines.

Acked-by: Viresh Kumar <vireshk@kernel.org>
Signed-off-by: Haoyu Lu <hechushiguitu666@gmail.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Simplify the code by making struct ata_scsi_transportt public, instead
of using separate variable ata_scsi_transport_template.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>