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charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org On 6/10/22 17:17, Serge Semin wrote: > Having greater than AHCI_MAX_PORTS (32) ports detected isn't that critical > from the further AHCI-platform initialization point of view since > exceeding the ports upper limit will cause allocating more resources than > will be used afterwards. But detecting too many child DT-nodes doesn't > seem right since it's very unlikely to have it on an ordinary platform. In > accordance with the AHCI specification there can't be more than 32 ports > implemented at least due to having the CAP.NP field of 5 bits wide and the > PI register of dword size. Thus if such situation is found the DTB must > have been corrupted and the data read from it shouldn't be reliable. Let's > consider that as an erroneous situation and halt further resources > allocation. > > Note it's logically more correct to have the nports set only after the > initialization value is checked for being sane. So while at it let's make > sure nports is assigned with a correct value. > > Signed-off-by: Serge Semin > Reviewed-by: Hannes Reinecke > > --- > > Changelog v2: > - Drop the else word from the child_nodes value checking if-else-if > statement (@Damien) and convert the after-else part into the ternary > operator-based statement. > > Changelog v4: > - Fix some logical mistakes in the patch log. (@Sergei Shtylyov) > --- > drivers/ata/libahci_platform.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c > index 814804582d1d..8aed7b29c7ab 100644 > --- a/drivers/ata/libahci_platform.c > +++ b/drivers/ata/libahci_platform.c > @@ -451,15 +451,22 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev, > } > } > > - hpriv->nports = child_nodes = of_get_child_count(dev->of_node); > + /* > + * Too many sub-nodes most likely means having something wrong with > + * the firmware. > + */ > + child_nodes = of_get_child_count(dev->of_node); > + if (child_nodes > AHCI_MAX_PORTS) { > + rc = -EINVAL; > + goto err_out; > + } > > /* > * If no sub-node was found, we still need to set nports to > * one in order to be able to use the > * ahci_platform_[en|dis]able_[phys|regulators] functions. > */ > - if (!child_nodes) > - hpriv->nports = 1; > + hpriv->nports = child_nodes ?: 1; This change is not necessary and makes the code far less easy to read. > > hpriv->phys = devm_kcalloc(dev, hpriv->nports, sizeof(*hpriv->phys), GFP_KERNEL); > if (!hpriv->phys) { -- Damien Le Moal Western Digital Research