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From 8572638ab99090b016ccc28ac1f69aa7759e43cf Mon Sep 17 00:00:00 2001
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From: Robert Milasan <rmilasan@suse.com>
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Date: Thu, 12 Jul 2012 15:56:34 +0000
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Subject: [PATCH] Persistent by_path links for ata devices
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With newer kernel we have the 'port_no' attribute,
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which allows us to construct a valid ata by-path link.
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With this patch ATA links of the form
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ata-<port>.[01]
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(for master/slave devices) or
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ata-<port>.<pmp>.0
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(for devices behind port multipliers)
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are generated.
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References: bnc#770910,FATE#317063
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Signed-off-by: Robert Milasan <rmilasan@suse.com>
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Signed-off-by: Hannes Reinecke <hare@suse.de>
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Downstream patch
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https://build.opensuse.org/package/view_file/Base:System/systemd/1001-re-enable-by_path-links-for-ata-devices.patch
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Resolves: #1045498
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---
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 src/udev/udev-builtin-path_id.c | 53 +++++++++++++++++++++++++++++++----------
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 1 file changed, 41 insertions(+), 12 deletions(-)
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diff --git a/src/udev/udev-builtin-path_id.c b/src/udev/udev-builtin-path_id.c
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index b6749aab7..bb0a6242a 100644
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--- a/src/udev/udev-builtin-path_id.c
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+++ b/src/udev/udev-builtin-path_id.c
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@@ -426,6 +426,46 @@ static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char *
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         return parent;
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 }
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+static struct udev_device *handle_ata(struct udev_device *parent, char **path)
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+{
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+        struct udev *udev  = udev_device_get_udev(parent);
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+        struct udev_device *hostdev, *portdev;
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+        int host, bus, target, lun, port_no;
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+        const char *name, *atahost, *port;
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+
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+        hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
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+        if (hostdev == NULL)
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+                return NULL;
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+
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+        name = udev_device_get_sysname(parent);
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+        if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
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+                return NULL;
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+
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+        /* The ata port is the parent of the SCSI host */
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+        hostdev = udev_device_get_parent(hostdev);
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+        atahost = udev_device_get_sysname(hostdev);
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+        if (strncmp(atahost, "ata", 3))
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+                return NULL;
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+
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+        /* ATA port number is found in 'port_no' attribute */
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+        portdev = udev_device_new_from_subsystem_sysname(udev, "ata_port",
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+                                                         atahost);
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+        port = udev_device_get_sysattr_value(portdev, "port_no");
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+        if (!port || sscanf(port, "%d", &port_no) != 1) {
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+                hostdev = NULL;
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+                goto out;
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+        }
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+        if (bus != 0)
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+                /* Devices behind port multiplier have a bus != 0*/
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+                path_prepend(path, "ata-%u.%u.0", port_no, bus);
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+        else
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+                /* Master/slave are distinguished by target id */
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+                path_prepend(path, "ata-%u.%u", port_no, target);
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+out:
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+        udev_device_unref(portdev);
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+        return hostdev;
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+}
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+
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 static struct udev_device *handle_scsi(struct udev_device *parent, char **path, bool *supported_parent) {
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         const char *devtype;
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         const char *name;
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@@ -465,19 +505,8 @@ static struct udev_device *handle_scsi(struct udev_device *parent, char **path,
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                 goto out;
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         }
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-        /*
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-         * We do not support the ATA transport class, it uses global counters
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-         * to name the ata devices which numbers spread across multiple
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-         * controllers.
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-         *
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-         * The real link numbers are not exported. Also, possible chains of ports
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-         * behind port multipliers cannot be composed that way.
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-         *
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-         * Until all that is solved at the kernel level, there are no by-path/
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-         * links for ATA devices.
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-         */
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         if (strstr(name, "/ata") != NULL) {
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-                parent = NULL;
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+                parent = handle_ata(parent, path);
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                 goto out;
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         }
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