RE: PATCH [2/8] scsi: megaraid_sas - add module param fast_load
- From: "Yang, Bo" <Bo.Yang@xxxxxxx>
- Date: Tue, 6 Nov 2007 12:04:31 -0700
Re-Sending:
Christoph,
The e-mail I sent out on Oct. 31st was bounced back, I re-send it again.
I see that scsi_scan_host_selected is in scsi_priv.h and currently is
not used by any other driver. The scsi_priv.h is not part of the include
dir (/include/scsi). One of the major Linux distro's don't even include
this file in /usr/src/kernels. Also it looks like at this time this
function may not be available (not exported?) for driver modules to use.
Even if I include scsi_priv.h I get "unknown symbol" for this function
while loading.
May be in the long run we can solve all these issues to call
scsi_scan_host_selected. However, the current implementation works fine
and has been tested by LSI and others. This implementation doesn't break
any protocol nor does it adversely affect any driver functionality.
In a future update soon I will modify the comment on proc/scsi and
remove the extra braces you have pointed out. Please accept the current
implementation/patches.
Regards,
Bo Yang
------------------------------------------------------------------------
------------------------
From: Yang, Bo
Sent: Wednesday, October 31, 2007 9:46 AM
To: Christoph Hellwig
Cc: linux-scsi@xxxxxxxxxxxxxxx; James.Bottomley@xxxxxxxxxxxx;
akpm@xxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Patro, Sumant; Kolli, Neela
Subject: RE: PATCH [2/8] scsi: megaraid_sas - add module param fast_load
Christoph,
I see that scsi_scan_host_selected is in scsi_priv.h and currently is
not used by any other driver. The scsi_priv.h is not part of the include
dir (/include/scsi). One of the major Linux distro's don't even include
this file in /usr/src/kernels. Also it looks like at this time this
function may not be available (not exported?) for driver modules to use.
Even if I include scsi_priv.h I get "unknown symbol" for this function
while loading.
May be in the long run we can solve all these issues to call
scsi_scan_host_selected. However, the current implementation works fine
and has been tested by LSI and others. This implementation doesn't break
any protocol nor does it adversely affect any driver functionality.
In a future update soon I will modify the comment on proc/scsi and
remove the extra braces you have pointed out. Please accept the current
implementation/patches.
Regards,
Bo Yang
-----Original Message-----
From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx]
Sent: Tuesday, October 30, 2007 1:37 PM
To: Yang, Bo
Cc: linux-scsi@xxxxxxxxxxxxxxx; James.Bottomley@xxxxxxxxxxxx;
akpm@xxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Patro, Sumant
Subject: Re: PATCH [2/8] scsi: megaraid_sas - add module param fast_load
On Mon, Oct 01, 2007 at 11:46:51AM -0400, bo yang wrote:
+/*
+ * Fast driver load option, skip scanning for physical devices during
+ * load. This would result in physical devices being skipped during
+ * driver load time. These can be later added though,
+ * using /proc/scsi/scsi
+ */
/proc/scsi/scsi is deprecated, so please don't recommend it here.
The proper way is the scan attribute of the scsi host.
+static unsigned int fast_load;"\
+module_param_named(fast_load, fast_load, int, 0);
+MODULE_PARM_DESC(fast_load,
+ "megasas: Faster loading of the driver, skips physical devices!
+ "(default = 0)");
This should show up in sysfs.
+static struct megasas_instance *megasas_lookup_instance(u16 host_no)
+{
+ int i;
+
+ for (i = 0; i < megasas_mgmt_info.max_index; i++) {
+ if ((megasas_mgmt_info.instance[i]) &&
+ (megasas_mgmt_info.instance[i]->host->host_no
+ == host_no))
no need for the braces here. This should be:
if (megasas_mgmt_info.instance[i] &&
megasas_mgmt_info.instance[i]->host->host_no ==
host_no)
+static int megasas_slave_alloc(struct scsi_device *sdev) {{
+ struct megasas_instance *instance;
+ int tmp_fastload = fast_load;
+
+ instance = megasas_lookup_instance(sdev->host->host_no);
+
+ if (tmp_fastload && sdev->channel < MEGASAS_MAX_PD_CHANNELS) {
+ if ((sdev->id == MEGASAS_MAX_DEV_PER_CHANNEL -1) &&
+ (sdev->channel == MEGASAS_MAX_PD_CHANNELS - 1))
+is
+ /*
+ * If fast load option was set and scan for last device
+ * over, reset the fast_load flag so that during apossible
+ * next scan, devices can be made available
+ */
+ fast_load = 0;
+ }
+ return -ENXIO;
+ }
+
+ return 0;
+}
This is a rather complicated and fragile way to implement this feature.
I'd recomment to change the call to scsi_scan_host in megasas_io_attach
to something like:
if (fast_load) {
int channel;
for (channel = 0; channel < MEGASAS_MAX_PD_CHANNELS;
channel++) {
scsi_scan_host_selected(host, channel,
SCAN_WILD_CARD,
SCAN_WILD_CARD, 0);
}
} else {
scsi_scan_host(host);
}
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