From e038e81fb63849ec43121cca04d8e7ca28861cf2 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 30 Aug 2012 14:52:55 +0000
Subject: [PATCH] scst_sysfs: Add EAGAIN fault injection code.

To do: update scst/Makefile and scst/README with more information about the
CONFIG_SCST_DEBUG_SYSFS_EAGAIN configuration option.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@4499 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 scst/src/scst_sysfs.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/scst/src/scst_sysfs.c b/scst/src/scst_sysfs.c
index 3dcba8bff..6b32fc2aa 100644
--- a/scst/src/scst_sysfs.c
+++ b/scst/src/scst_sysfs.c
@@ -523,6 +523,23 @@ int scst_sysfs_queue_wait_work(struct scst_sysfs_work_item *work)
 			"failed: %d", atomic_read(&uid_thread_name),
 			(int)PTR_ERR(t));
 
+#ifdef CONFIG_SCST_DEBUG_SYSFS_EAGAIN
+	{
+		static int cnt;
+
+		if (!work->read_only_action || cnt++ % 4 < 3) {
+			/*
+			 * Helps testing user space code that writes to or
+			 * reads from SCST sysfs variables.
+			 */
+			timeout = 0;
+			rc = 0;
+			res = -EAGAIN;
+			goto out_put;
+		}
+	}
+#endif
+
 	while (1) {
 		rc = wait_for_completion_interruptible_timeout(
 			&work->sysfs_work_done, timeout);