Re: [PATCH v5 5/6] ata: libata: Do not leave ata_host_stop() registered when activation fails

[Damien Le Moal <dlemoal@kernel.org>]

On 2026/09/15 15:41, Niklas Cassel wrote:
> ata_host_start() registers ata_host_stop() as a devres action as soon as
> it has succeeded, which hands the release of the host resources over to
> devres: ->port_stop() and ->host_stop() are then called by the driver
> core when probe() fails.
> 
> ata_host_activate() and ahci_host_activate_multi_irqs() can both fail
> after ata_host_start() has succeeded, e.g. if devm_request_irq() or
> ata_host_register() fails, and they return the error with the devres
> action still registered. A driver which releases the host resources in
> its probe() error path therefore releases them twice: once itself and
> once through ->host_stop().
> 
> All ahci-platform drivers are in that situation, e.g. ahci_probe() calls
> ahci_platform_disable_resources() while ahci_host_stop() does the same
> through devres. This gives refcount underflow warnings from the clk,
> regulator and phy cores and, for shared resources, can disable resources
> which are still in use by other devices.
> 
> Add ata_host_undo_start(), which stops the ports and drops the devres
> action without calling ->host_stop(), and call it from both activation
> helpers when they fail. Releasing the host resources on failure is then
> always left to the caller, which is what all callers having a probe()
> error path already assume.
> 
> This changes the semantics for the drivers which implement ->host_stop()
> while also completely lacking error handling for the activate host call.
> Add activate host error handling for sata_qstor and sata_fsl. For
> sata_fsl this also means that hcr_base and host_priv are now released
> when activating the host fails, which ->host_stop() did not do when
> ata_host_start() itself failed.
> 
> Note that ata_pci_sff_activate_host() is deliberately left as is: none of
> its callers releases the host resources in its probe() error path, they
> all rely on ->host_stop() being called by devres, including
> ata_pci_init_one(), which releases the devres group of the host itself.
> 
> Fixes: 1896b15eddb4 ("ahci_platform: perform platform exit in host_stop() hook")
> Cc: stable@vger.kernel.org
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Looks good.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research