From 21465eda9eafa275ed11c27779d90aa95559b6f6 Mon Sep 17 00:00:00 2001
From: Brian King <brking@linux.vnet.ibm.com>
Date: Mon, 8 Dec 2008 17:01:47 -0600
Subject: [PATCH] [SCSI] ibmvscsi: Don't fail EH due to insufficient resources
The ibmvscsi driver currently has a bug in it which can result
in it using up all its event structs for commands. If something
results in all those commands timing out, we won't have any resources
left to send aborts or resets. This results in escalating to a host reset
in order to recover, which is a bit heavy handed. This fixes it
by reducing can_queue by two in order to have resources to do EH.
It also changes the max_requests module parameter so that it is not
writable at runtime, since the code really does not handle it changing
at runtime.
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
drivers/scsi/ibmvscsi/ibmvscsi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 6cad1758243a58..868d35ea01bba1 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -107,7 +107,7 @@ module_param_named(max_channel, max_channel, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_channel, "Largest channel value");
module_param_named(init_timeout, init_timeout, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds");
-module_param_named(max_requests, max_requests, int, S_IRUGO | S_IWUSR);
+module_param_named(max_requests, max_requests, int, S_IRUGO);
MODULE_PARM_DESC(max_requests, "Maximum requests for this adapter");
/* ------------------------------------------------------------
@@ -1657,7 +1657,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
vdev->dev.driver_data = NULL;
- driver_template.can_queue = max_requests;
+ driver_template.can_queue = max_requests - 2;
host = scsi_host_alloc(&driver_template, sizeof(*hostdata));
if (!host) {
dev_err(&vdev->dev, "couldn't allocate host data\n");
--
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