[SCSI] libata: reset once

Hotplug testing with libsas currently encounters a 55 second wait for link recovery to give up. In the case where the user trusts the response time of their devices permit the recovery attempts to be limited to one. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Jeff Garzik <jgarzik@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>

[SCSI] libata: reset once
Hotplug testing with libsas currently encounters a 55 second wait for link recovery to give up. In the case where the user trusts the response time of their devices permit the recovery attempts to be limited to one. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Jeff Garzik <jgarzik@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Dan Williams · James Bottomley
1 parent d9875690d9
Showing 4 changed files with 7 additions and 0 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
drivers/ata/libata-core.c
drivers/ata/libata-eh.c
include/linux/libata.h
@@ -1350,6 +1350,9 @@
 			* nohrst, nosrst, norst: suppress hard, soft
                           and both resets.
  
+			* rstonce: only attempt one reset during
+			  hot-unplug link recovery
+
 			* dump_id: dump IDENTIFY data.
  
 			If there are multiple matching configurations changing
@@ -6387,6 +6387,7 @@
 		{ "nohrst",	.lflags		= ATA_LFLAG_NO_HRST },
 		{ "nosrst",	.lflags		= ATA_LFLAG_NO_SRST },
 		{ "norst",	.lflags		= ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST },
+		{ "rstonce",	.lflags		= ATA_LFLAG_RST_ONCE },
 	};
 	char *start = *cur, *p = *cur;
 	char *id, *val, *endp;
@@ -2623,6 +2623,8 @@
 	 */
 	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
 		max_tries++;
+	if (link->flags & ATA_LFLAG_RST_ONCE)
+		max_tries = 1;
 	if (link->flags & ATA_LFLAG_NO_HRST)
 		hardreset = NULL;
 	if (link->flags & ATA_LFLAG_NO_SRST)
@@ -184,6 +184,7 @@
 	ATA_LFLAG_DISABLED	= (1 << 6), /* link is disabled */
 	ATA_LFLAG_SW_ACTIVITY	= (1 << 7), /* keep activity stats */
 	ATA_LFLAG_NO_LPM	= (1 << 8), /* disable LPM on this link */
+	ATA_LFLAG_RST_ONCE	= (1 << 9), /* limit recovery to one reset */
  
 	/* struct ata_port flags */
 	ATA_FLAG_SLAVE_POSS	= (1 << 0), /* host supports slave dev */
...	...	@@ -1350,6 +1350,9 @@
1350	1350	* nohrst, nosrst, norst: suppress hard, soft
1351	1351	and both resets.
1352	1352
	1353	+ * rstonce: only attempt one reset during
	1354	+ hot-unplug link recovery
	1355	+
1353	1356	* dump_id: dump IDENTIFY data.
1354	1357
1355	1358	If there are multiple matching configurations changing
...	...	@@ -6387,6 +6387,7 @@
6387	6387	{ "nohrst", .lflags = ATA_LFLAG_NO_HRST },
6388	6388	{ "nosrst", .lflags = ATA_LFLAG_NO_SRST },
6389	6389	{ "norst", .lflags = ATA_LFLAG_NO_HRST \| ATA_LFLAG_NO_SRST },
	6390	+ { "rstonce", .lflags = ATA_LFLAG_RST_ONCE },
6390	6391	};
6391	6392	char start = cur, p = cur;
6392	6393	char id, val, *endp;
...	...	@@ -2623,6 +2623,8 @@
2623	2623	*/
2624	2624	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
2625	2625	max_tries++;
	2626	+ if (link->flags & ATA_LFLAG_RST_ONCE)
	2627	+ max_tries = 1;
2626	2628	if (link->flags & ATA_LFLAG_NO_HRST)
2627	2629	hardreset = NULL;
2628	2630	if (link->flags & ATA_LFLAG_NO_SRST)
...	...	@@ -184,6 +184,7 @@
184	184	ATA_LFLAG_DISABLED = (1 << 6), /* link is disabled */
185	185	ATA_LFLAG_SW_ACTIVITY = (1 << 7), /* keep activity stats */
186	186	ATA_LFLAG_NO_LPM = (1 << 8), /* disable LPM on this link */
	187	+ ATA_LFLAG_RST_ONCE = (1 << 9), /* limit recovery to one reset */
187	188
188	189	/* struct ata_port flags */
189	190	ATA_FLAG_SLAVE_POSS = (1 << 0), /* host supports slave dev */