[PATCH] SCSI: limit mode sense usage

Re-roll of the patch against 2.6.0-test6 to allow overriding or setting of
mode sense related flags, includes Alan Stern's as95 patch minus his
scsiglue.c changes.

Moves scsi_devinfo.h for use outside of drivers/scsi, and adds three new
devinfo flags:

	BLIST_MS_SKIP_PAGE_08
	BLIST_MS_SKIP_PAGE_3F
	BLIST_USE_10_BYTE_MS

Adds a per host template flags, and use of it in scsiglue.c. The per host
value can be overridden by a devinfo entry, the patch does not allow
scsi_default_dev_flags to override default host values.

USB mass storage and removable media (for testing mode page 3f use) were
not tested, if you have a USB storage device that still chokes on mode
sense 3f please give this a spin.

 drivers/scsi/scsi_devinfo.c    |   15 +++++++++++----
 drivers/scsi/scsi_devinfo.h    |   17 -----------------
 drivers/scsi/scsi_priv.h       |    3 ++-
 drivers/scsi/scsi_scan.c       |   17 +++++++++++++----
 drivers/scsi/sd.c              |    9 +++++++++
 drivers/usb/storage/scsiglue.c |    8 ++++----
 include/scsi/scsi_device.h     |    2 ++
 include/scsi/scsi_devinfo.h    |   22 ++++++++++++++++++++++
 include/scsi/scsi_host.h       |    6 ++++++
 9 files changed, 69 insertions(+), 30 deletions(-)

drivers/scsi/scsi_devinfo.c

@@ -6,10 +6,11 @@
 #include <linux/moduleparam.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <scsi/scsi_devinfo.h>
 
 #include "scsi.h"
+#include "hosts.h"
 #include "scsi_priv.h"
-#include "scsi_devinfo.h"
 
 /*
  * scsi_dev_info_list: structure to hold black/white listed devices.
@@ -322,11 +323,17 @@ static int scsi_dev_info_list_add_str(char *dev_list)
  * Description:
  *     Search the scsi_dev_info_list for an entry matching @vendor and
  *     @model, if found, return the matching flags value, else return
- *     scsi_default_dev_flags.
+ *     the host or global default settings.
  **/
-int scsi_get_device_flags(unsigned char *vendor, unsigned char *model)
+int scsi_get_device_flags(struct scsi_device *sdev, unsigned char *vendor,
+			  unsigned char *model)
 {
 	struct scsi_dev_info_list *devinfo;
+	unsigned int bflags;
+
+	bflags = sdev->host->hostt->flags;
+	if (!bflags)
+		bflags = scsi_default_dev_flags;
 
 	list_for_each_entry(devinfo, &scsi_dev_info_list, dev_info_list) {
 		if (devinfo->compatible) {
@@ -378,7 +385,7 @@ int scsi_get_device_flags(unsigned char *vendor, unsigned char *model)
 				return devinfo->flags;
 		}
 	}
-	return scsi_default_dev_flags;
+	return bflags;
 }
 
 #ifdef CONFIG_SCSI_PROC_FS

drivers/scsi/scsi_priv.h

@@ -85,7 +85,8 @@ extern void scsi_init_cmd_from_req(struct scsi_cmnd *cmd,
 extern void __scsi_release_request(struct scsi_request *sreq);
 
 /* scsi_devinfo.c */
-extern int scsi_get_device_flags(unsigned char *vendor, unsigned char *model);
+extern int scsi_get_device_flags(struct scsi_device *sdev,
+				 unsigned char *vendor, unsigned char *model);
 extern int scsi_init_devinfo(void);
 extern void scsi_exit_devinfo(void);
 

drivers/scsi/scsi_scan.c

@@ -35,10 +35,10 @@
 #include "scsi.h"
 #include "hosts.h"
 #include <scsi/scsi_driver.h>
+#include <scsi/scsi_devinfo.h>
 
 #include "scsi_priv.h"
 #include "scsi_logging.h"
-#include "scsi_devinfo.h"
 
 #define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
 	" SCSI scanning, some SCSI devices might not be configured\n"
@@ -365,7 +365,7 @@ static void scsi_probe_lun(struct scsi_request *sreq, char *inq_result,
 	 * bit fields in Scsi_Device, so bflags need not be passed as an
 	 * argument.
 	 */
-	*bflags |= scsi_get_device_flags(&inq_result[8], &inq_result[16]);
+	*bflags |= scsi_get_device_flags(sdev, &inq_result[8], &inq_result[16]);
 
 	possible_inq_resp_len = (unsigned char) inq_result[4] + 5;
 	if (BLIST_INQUIRY_36 & *bflags)
@@ -625,7 +625,15 @@ static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
 
 	sdev->use_10_for_rw = 1;
-	sdev->use_10_for_ms = 0;
+
+	if (*bflags & BLIST_MS_SKIP_PAGE_08)
+		sdev->skip_ms_page_8 = 1;
+
+	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
+		sdev->skip_ms_page_3f = 1;
+
+	if (*bflags & BLIST_USE_10_BYTE_MS)
+		sdev->use_10_for_ms = 1;
 
 	if(sdev->host->hostt->slave_configure)
 		sdev->host->hostt->slave_configure(sdev);
@@ -678,7 +686,8 @@ static int scsi_probe_and_add_lun(struct Scsi_Host *host,
 			if (sdevp)
 				*sdevp = sdev;
 			if (bflagsp)
-				*bflagsp = scsi_get_device_flags(sdev->vendor,
+				*bflagsp = scsi_get_device_flags(sdev,
+								 sdev->vendor,
 								 sdev->model);
 			return SCSI_SCAN_LUN_PRESENT;
 		}

drivers/scsi/sd.c

@@ -1057,6 +1057,11 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
 	int res;
 	struct scsi_mode_data data;
 
+	if (sdkp->device->skip_ms_page_3f) {
+		printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
+		return;
+	}
+
 	/*
 	 * First attempt: ask for all pages (0x3F), but only 4 bytes.
 	 * We have to start carefully: some devices hang if we ask
@@ -1103,6 +1108,8 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
 	const int modepage = 0x08; /* current values, cache page */
 	struct scsi_mode_data data;
 
+	if (sdkp->device->skip_ms_page_8)
+		goto defaults;
 
 	/* cautiously ask */
 	res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, 4, &data);
@@ -1160,6 +1167,8 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
 		printk(KERN_ERR "%s: asking for cache data failed\n",
 		       diskname);
 	}
+
+defaults:
 	printk(KERN_ERR "%s: assuming drive cache: write through\n",
 	       diskname);
 	sdkp->WCE = 0;

drivers/usb/storage/scsiglue.c

@@ -51,6 +51,7 @@
 
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <scsi/scsi_devinfo.h>
 
 
 /***********************************************************************
@@ -64,10 +65,6 @@ static const char* host_info(struct Scsi_Host *host)
 
 static int slave_configure (struct scsi_device *sdev)
 {
-	/* set device to use 10-byte commands where possible */
-	sdev->use_10_for_ms = 1;
-	sdev->use_10_for_rw = 1;
-
 	/* this is to satisify the compiler, tho I don't think the 
 	 * return code is ever checked anywhere. */
 	return 0;
@@ -324,6 +321,9 @@ struct scsi_host_template usb_stor_host_template = {
 	/* emulated HBA */
 	.emulated =			TRUE,
 
+	/* modify scsi_device bits on probe */
+	.flags = (BLIST_MS_SKIP_PAGE_08 | BLIST_USE_10_BYTE_MS),
+
 	/* module management */
 	.module =			THIS_MODULE
 };

include/scsi/scsi_device.h

@@ -86,6 +86,8 @@ struct scsi_device {
 				     * because we did a bus reset. */
 	unsigned use_10_for_rw:1; /* first try 10-byte read / write */
 	unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
+	unsigned skip_ms_page_8:1;	/* do not use MODE SENSE page 0x08 */
+	unsigned skip_ms_page_3f:1;	/* do not use MODE SENSE page 0x3f */
 	unsigned no_start_on_add:1;	/* do not issue start on add */
 
 	unsigned int device_blocked;	/* Device returned QUEUE_FULL. */

drivers/scsi/scsi_devinfo.h → include/scsi/scsi_devinfo.h

-
+#ifndef _SCSI_SCSI_DEVINFO_H
+#define _SCSI_SCSI_DEVINFO_H
 /*
  * Flags for SCSI devices that need special treatment
  */
@@ -15,3 +16,7 @@
 #define BLIST_INQUIRY_36	0x400	/* override additional length field */
 #define BLIST_INQUIRY_58	0x800	/* ... for broken inquiry responses */
 #define BLIST_NOSTARTONADD	0x1000	/* do not do automatic start on add */
+#define BLIST_MS_SKIP_PAGE_08	0x2000	/* do not send ms page 0x08 */
+#define BLIST_MS_SKIP_PAGE_3F	0x4000	/* do not send ms page 0x3f */
+#define BLIST_USE_10_BYTE_MS	0x8000	/* use 10 byte ms before 6 byte ms */
+#endif

include/scsi/scsi_host.h

@@ -344,6 +344,12 @@ struct scsi_host_template {
 	 * module_init/module_exit.
 	 */
 	struct list_head legacy_hosts;
+
+	/*
+	 * Default flags settings, these modify the setting of scsi_device
+	 * bits.
+	 */
+	unsigned int flags;
 };
 
 /*