libata: fix attach error handling (842faa6c) · Commits · 戴 / test

New device attach path in ata_eh_revalidate_and_attach() is divided into two separate loops because ATA requires IDENTIFY to be issued to slave first while the user expects to see device probe messages from the master device. new_mask is used to track which devices are the new ones between the first loop and the second. This usually works well but if an error occurs during configuration stage, ata_dev_revalidate_and_attach() returns with error code and forgets new_mask. On the retry run, dev->class is set and new_mask for the device is clear, so the device just gets revalidated and thus ends up skipping post-configuration procedure including scheduling of SCSI_HOTPLUG for the device. When this occurs, ATA part of probing works fine but SCSI probing usually doesn't happen and makes the device unreachable. The behavior has been around for a very long time but it has been uncovered with the recent addition of 1_5_GBPS horkage which uses -EAGAIN return value from ata_dev_configure() to restart the probing sequence after forcing cable speed. This can be fixed by making sure dev->class is permanently set only after all configurations are successfully complete. Fix it. Signed-off-by:

Tejun Heo <tj@kernel.org> Reported-by:

Tim Connors <tconnors+linuxkml@astro.swin.edu.au> Signed-off-by:

Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-eh.c

+17 −4

Original line number	Diff line number	Diff line
		@@ -2783,6 +2783,12 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
		} else if (dev->class == ATA_DEV_UNKNOWN &&
		ehc->tries[dev->devno] &&
		ata_class_enabled(ehc->classes[dev->devno])) {
		/* Temporarily set dev->class, it will be
		* permanently set once all configurations are
		* complete. This is necessary because new
		* device configuration is done in two
		* separate loops.
		*/
		dev->class = ehc->classes[dev->devno];

		if (dev->class == ATA_DEV_PMP)
		@@ -2790,6 +2796,11 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
		else
		rc = ata_dev_read_id(dev, &dev->class,
		readid_flags, dev->id);

		/* read_id might have changed class, store and reset */
		ehc->classes[dev->devno] = dev->class;
		dev->class = ATA_DEV_UNKNOWN;

		switch (rc) {
		case 0:
		/* clear error info accumulated during probe */
		@@ -2799,13 +2810,11 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
		case -ENOENT:
		/* IDENTIFY was issued to non-existent
		* device. No need to reset. Just
		* thaw and kill the device.
		* thaw and ignore the device.
		*/
		ata_eh_thaw_port(ap);
		dev->class = ATA_DEV_UNKNOWN;
		break;
		default:
		dev->class = ATA_DEV_UNKNOWN;
		goto err;
		}
		}
		@@ -2826,11 +2835,15 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
		dev->class == ATA_DEV_PMP)
		continue;

		dev->class = ehc->classes[dev->devno];

		ehc->i.flags \|= ATA_EHI_PRINTINFO;
		rc = ata_dev_configure(dev);
		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
		if (rc)
		if (rc) {
		dev->class = ATA_DEV_UNKNOWN;
		goto err;
		}

		spin_lock_irqsave(ap->lock, flags);
		ap->pflags \|= ATA_PFLAG_SCSI_HOTPLUG;

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