[PATCH v2 2/3] lpd: marvell: handle non-unique/duplicate location codes

On some systems, it's been observed that different disks of the Marvell
SATA HDD controller might be listed with the very same location code.

This could cause an user to specify a device by location code, and have
the wrong device identified; if the service operation is a hotplug/pull
the disk, that error would cause serious problems.

Even though this might be a problem that requires a fix elsewhere, it's
still possible to support such scenario, with the usysident option that
specify the element by device name (e.g., '-d sda') instead of location
code (e.g., '-l -B0-T0-L0').

This patch adds a simple check and workaround for that -- restricted to
the Marvell devices (TYPE_MARVELL); once a device match is found:

- if the device is specified by device name,
  then proceed normally.

- if the device is specified by location code,
  then check for other devices with this location code.

  - if not found,
    then proceed normally.

  - else,
    stop, and ask the user to specify the device name with '-d'.

Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
---
Changelog:
  v2:
  - no changes.

 lpd/usysident.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/lpd/usysident.c b/lpd/usysident.c
index 9eed946..e3dcad0 100644
--- a/lpd/usysident.c
+++ b/lpd/usysident.c
@@ -113,6 +113,7 @@ main(int argc, char **argv)
 	char	*othervalue = NULL;
 	struct	loc_code *current;
 	struct	loc_code *list = NULL;
+	struct	loc_code *list_start = NULL;
 
 	program_name = argv[0];
 	if (probe_indicator() != 0)
@@ -345,12 +346,14 @@ main(int argc, char **argv)
 		strncpy(temp, lvalue, LOCATION_LENGTH);
 		temp[LOCATION_LENGTH - 1] = '\0';
 
+	list_start = list;
 retry:
-		current = get_indicator_for_loc_code(list, lvalue);
+		current = get_indicator_for_loc_code(list_start, lvalue);
 		if (!current) {
 			if (trunc) {
 				if (truncate_loc_code(lvalue)) {
 					truncated = 1;
+					list_start = list; /* start again */
 					goto retry;
 				}
 			}
@@ -363,6 +366,48 @@ retry:
 				fprintf(stdout, "Truncated location code : "
 					"%s\n", lvalue);
 
+			if (current->type == TYPE_MARVELL) {
+
+				/*
+				 * On some systems...
+				 * The Marvell SATA HDD controller may have one location code
+				 * for all disks. So, in order to uniquely identify a disk in
+				 * the list, the -d <dev_name> (dvalue) option must be used.
+				 *
+				 * eg, if the -l <loc_code> (lvalue) option is used then the
+				 * first disk in that location code will match, and it might
+				 * be the wrong disk!
+				 *
+				 * So, check if there is another list entry in this system
+				 * with the same location code as the current entry; if so,
+				 * only handle Marvell devices if '-d <dev_name>' is used.
+				 */
+				if (!dvalue &&
+				    get_indicator_for_loc_code(current->next, lvalue)) {
+					fprintf(stdout, "The Marvell HDD LEDs must be "
+						"specified by device name (-d option);"
+						" non-unique location codes found.\n");
+					rc = 1;
+					goto no_retry;
+				}
+
+				/*
+				 * At this point, after the check for "if (dvalue && lvalue)",
+				 * if dvalue is non-NULL then lvalue is from get_loc_code_dev()
+				 * (based on device name: dvalue), and dvalue is from cmdline.
+				 *
+				 * So, if dvalue is non-NULL and doesn't match the device name
+				 * specified in 'current' (found location code), let's try the
+				 * next elements in the list (which may match the device name);
+				 * for this we need to retry, re-starting on the next element.
+				 */
+				if (dvalue && current->devname &&
+				    strncmp(dvalue, current->devname, DEV_LENGTH)) {
+					list_start = current->next;
+					goto retry;
+				}
+			}
+
 			if (svalue) {
 				rc = get_indicator_state(indicator, current,
 							 &state);
@@ -388,6 +433,7 @@ retry:
 			}
 		} /* if-else end */
 	} /* lvalue end */
+no_retry:
 
 	/* Turn on/off all indicators */
 	if (othervalue) {
-- 
1.8.3.1


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