Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1740 insertions, 0 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
new file mode 100644
index 00000000000..19afb25e44d
--- /dev/null
+++ b/drivers/scsi/sd.c
@@ -0,0 +1,1740 @@
+/*
+ *      sd.c Copyright (C) 1992 Drew Eckhardt
+ *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
+ *
+ *      Linux scsi disk driver
+ *              Initial versions: Drew Eckhardt
+ *              Subsequent revisions: Eric Youngdale
+ *	Modification history:
+ *       - Drew Eckhardt <drew@colorado.edu> original
+ *       - Eric Youngdale <eric@andante.org> add scatter-gather, multiple 
+ *         outstanding request, and other enhancements.
+ *         Support loadable low-level scsi drivers.
+ *       - Jirka Hanika <geo@ff.cuni.cz> support more scsi disks using 
+ *         eight major numbers.
+ *       - Richard Gooch <rgooch@atnf.csiro.au> support devfs.
+ *	 - Torben Mathiasen <tmm@image.dk> Resource allocation fixes in 
+ *	   sd_init and cleanups.
+ *	 - Alex Davis <letmein@erols.com> Fix problem where partition info
+ *	   not being read in sd_open. Fix problem where removable media 
+ *	   could be ejected after sd_open.
+ *	 - Douglas Gilbert <dgilbert@interlog.com> cleanup for lk 2.5.x
+ *	 - Badari Pulavarty <pbadari@us.ibm.com>, Matthew Wilcox 
+ *	   <willy@debian.org>, Kurt Garloff <garloff@suse.de>: 
+ *	   Support 32k/1M disks.
+ *
+ *	Logging policy (needs CONFIG_SCSI_LOGGING defined):
+ *	 - setting up transfer: SCSI_LOG_HLQUEUE levels 1 and 2
+ *	 - end of transfer (bh + scsi_lib): SCSI_LOG_HLCOMPLETE level 1
+ *	 - entering sd_ioctl: SCSI_LOG_IOCTL level 1
+ *	 - entering other commands: SCSI_LOG_HLQUEUE level 3
+ *	Note: when the logging level is set by the user, it must be greater
+ *	than the level indicated above to trigger output.	
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/bio.h>
+#include <linux/genhd.h>
+#include <linux/hdreg.h>
+#include <linux/errno.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/blkpg.h>
+#include <linux/kref.h>
+#include <linux/delay.h>
+#include <asm/uaccess.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_request.h>
+#include <scsi/scsicam.h>
+
+#include "scsi_logging.h"
+
+/*
+ * More than enough for everybody ;)  The huge number of majors
+ * is a leftover from 16bit dev_t days, we don't really need that
+ * much numberspace.
+ */
+#define SD_MAJORS	16
+
+/*
+ * This is limited by the naming scheme enforced in sd_probe,
+ * add another character to it if you really need more disks.
+ */
+#define SD_MAX_DISKS	(((26 * 26) + 26 + 1) * 26)
+
+/*
+ * Time out in seconds for disks and Magneto-opticals (which are slower).
+ */
+#define SD_TIMEOUT		(30 * HZ)
+#define SD_MOD_TIMEOUT		(75 * HZ)
+
+/*
+ * Number of allowed retries
+ */
+#define SD_MAX_RETRIES		5
+#define SD_PASSTHROUGH_RETRIES	1
+
+static void scsi_disk_release(struct kref *kref);
+
+struct scsi_disk {
+	struct scsi_driver *driver;	/* always &sd_template */
+	struct scsi_device *device;
+	struct kref	kref;
+	struct gendisk	*disk;
+	unsigned int	openers;	/* protected by BKL for now, yuck */
+	sector_t	capacity;	/* size in 512-byte sectors */
+	u32		index;
+	u8		media_present;
+	u8		write_prot;
+	unsigned	WCE : 1;	/* state of disk WCE bit */
+	unsigned	RCD : 1;	/* state of disk RCD bit, unused */
+};
+
+static DEFINE_IDR(sd_index_idr);
+static DEFINE_SPINLOCK(sd_index_lock);
+
+/* This semaphore is used to mediate the 0->1 reference get in the
+ * face of object destruction (i.e. we can't allow a get on an
+ * object after last put) */
+static DECLARE_MUTEX(sd_ref_sem);
+
+static int sd_revalidate_disk(struct gendisk *disk);
+static void sd_rw_intr(struct scsi_cmnd * SCpnt);
+
+static int sd_probe(struct device *);
+static int sd_remove(struct device *);
+static void sd_shutdown(struct device *dev);
+static void sd_rescan(struct device *);
+static int sd_init_command(struct scsi_cmnd *);
+static int sd_issue_flush(struct device *, sector_t *);
+static void sd_end_flush(request_queue_t *, struct request *);
+static int sd_prepare_flush(request_queue_t *, struct request *);
+static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
+		 struct scsi_request *SRpnt, unsigned char *buffer);
+
+static struct scsi_driver sd_template = {
+	.owner			= THIS_MODULE,
+	.gendrv = {
+		.name		= "sd",
+		.probe		= sd_probe,
+		.remove		= sd_remove,
+		.shutdown	= sd_shutdown,
+	},
+	.rescan			= sd_rescan,
+	.init_command		= sd_init_command,
+	.issue_flush		= sd_issue_flush,
+	.prepare_flush		= sd_prepare_flush,
+	.end_flush		= sd_end_flush,
+};
+
+/*
+ * Device no to disk mapping:
+ * 
+ *       major         disc2     disc  p1
+ *   |............|.............|....|....| <- dev_t
+ *    31        20 19          8 7  4 3  0
+ * 
+ * Inside a major, we have 16k disks, however mapped non-
+ * contiguously. The first 16 disks are for major0, the next
+ * ones with major1, ... Disk 256 is for major0 again, disk 272 
+ * for major1, ... 
+ * As we stay compatible with our numbering scheme, we can reuse 
+ * the well-know SCSI majors 8, 65--71, 136--143.
+ */
+static int sd_major(int major_idx)
+{
+	switch (major_idx) {
+	case 0:
+		return SCSI_DISK0_MAJOR;
+	case 1 ... 7:
+		return SCSI_DISK1_MAJOR + major_idx - 1;
+	case 8 ... 15:
+		return SCSI_DISK8_MAJOR + major_idx - 8;
+	default:
+		BUG();
+		return 0;	/* shut up gcc */
+	}
+}
+
+#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,kref)
+
+static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
+{
+	return container_of(disk->private_data, struct scsi_disk, driver);
+}
+
+static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
+{
+	struct scsi_disk *sdkp = NULL;
+
+	down(&sd_ref_sem);
+	if (disk->private_data == NULL)
+		goto out;
+	sdkp = scsi_disk(disk);
+	kref_get(&sdkp->kref);
+	if (scsi_device_get(sdkp->device))
+		goto out_put;
+	up(&sd_ref_sem);
+	return sdkp;
+
+ out_put:
+	kref_put(&sdkp->kref, scsi_disk_release);
+	sdkp = NULL;
+ out:
+	up(&sd_ref_sem);
+	return sdkp;
+}
+
+static void scsi_disk_put(struct scsi_disk *sdkp)
+{
+	struct scsi_device *sdev = sdkp->device;
+
+	down(&sd_ref_sem);
+	kref_put(&sdkp->kref, scsi_disk_release);
+	scsi_device_put(sdev);
+	up(&sd_ref_sem);
+}
+
+/**
+ *	sd_init_command - build a scsi (read or write) command from
+ *	information in the request structure.
+ *	@SCpnt: pointer to mid-level's per scsi command structure that
+ *	contains request and into which the scsi command is written
+ *
+ *	Returns 1 if successful and 0 if error (or cannot be done now).
+ **/
+static int sd_init_command(struct scsi_cmnd * SCpnt)
+{
+	unsigned int this_count, timeout;
+	struct gendisk *disk;
+	sector_t block;
+	struct scsi_device *sdp = SCpnt->device;
+	struct request *rq = SCpnt->request;
+
+	timeout = sdp->timeout;
+
+	/*
+	 * SG_IO from block layer already setup, just copy cdb basically
+	 */
+	if (blk_pc_request(rq)) {
+		if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd))
+			return 0;
+
+		memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd));
+		if (rq_data_dir(rq) == WRITE)
+			SCpnt->sc_data_direction = DMA_TO_DEVICE;
+		else if (rq->data_len)
+			SCpnt->sc_data_direction = DMA_FROM_DEVICE;
+		else
+			SCpnt->sc_data_direction = DMA_NONE;
+
+		this_count = rq->data_len;
+		if (rq->timeout)
+			timeout = rq->timeout;
+
+		SCpnt->transfersize = rq->data_len;
+		SCpnt->allowed = SD_PASSTHROUGH_RETRIES;
+		goto queue;
+	}
+
+	/*
+	 * we only do REQ_CMD and REQ_BLOCK_PC
+	 */
+	if (!blk_fs_request(rq))
+		return 0;
+
+	disk = rq->rq_disk;
+	block = rq->sector;
+	this_count = SCpnt->request_bufflen >> 9;
+
+	SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
+			    "count=%d\n", disk->disk_name,
+			 (unsigned long long)block, this_count));
+
+	if (!sdp || !scsi_device_online(sdp) ||
+ 	    block + rq->nr_sectors > get_capacity(disk)) {
+		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n", 
+				 rq->nr_sectors));
+		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
+		return 0;
+	}
+
+	if (sdp->changed) {
+		/*
+		 * quietly refuse to do anything to a changed disc until 
+		 * the changed bit has been reset
+		 */
+		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
+		return 0;
+	}
+	SCSI_LOG_HLQUEUE(2, printk("%s : block=%llu\n",
+				   disk->disk_name, (unsigned long long)block));
+
+	/*
+	 * If we have a 1K hardware sectorsize, prevent access to single
+	 * 512 byte sectors.  In theory we could handle this - in fact
+	 * the scsi cdrom driver must be able to handle this because
+	 * we typically use 1K blocksizes, and cdroms typically have
+	 * 2K hardware sectorsizes.  Of course, things are simpler
+	 * with the cdrom, since it is read-only.  For performance
+	 * reasons, the filesystems should be able to handle this
+	 * and not force the scsi disk driver to use bounce buffers
+	 * for this.
+	 */
+	if (sdp->sector_size == 1024) {
+		if ((block & 1) || (rq->nr_sectors & 1)) {
+			printk(KERN_ERR "sd: Bad block number requested");
+			return 0;
+		} else {
+			block = block >> 1;
+			this_count = this_count >> 1;
+		}
+	}
+	if (sdp->sector_size == 2048) {
+		if ((block & 3) || (rq->nr_sectors & 3)) {
+			printk(KERN_ERR "sd: Bad block number requested");
+			return 0;
+		} else {
+			block = block >> 2;
+			this_count = this_count >> 2;
+		}
+	}
+	if (sdp->sector_size == 4096) {
+		if ((block & 7) || (rq->nr_sectors & 7)) {
+			printk(KERN_ERR "sd: Bad block number requested");
+			return 0;
+		} else {
+			block = block >> 3;
+			this_count = this_count >> 3;
+		}
+	}
+	if (rq_data_dir(rq) == WRITE) {
+		if (!sdp->writeable) {
+			return 0;
+		}
+		SCpnt->cmnd[0] = WRITE_6;
+		SCpnt->sc_data_direction = DMA_TO_DEVICE;
+	} else if (rq_data_dir(rq) == READ) {
+		SCpnt->cmnd[0] = READ_6;
+		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
+	} else {
+		printk(KERN_ERR "sd: Unknown command %lx\n", rq->flags);
+/* overkill 	panic("Unknown sd command %lx\n", rq->flags); */
+		return 0;
+	}
+
+	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n", 
+		disk->disk_name, (rq_data_dir(rq) == WRITE) ? 
+		"writing" : "reading", this_count, rq->nr_sectors));
+
+	SCpnt->cmnd[1] = 0;
+	
+	if (block > 0xffffffff) {
+		SCpnt->cmnd[0] += READ_16 - READ_6;
+		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
+		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
+		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
+		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
+		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
+		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
+		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
+		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
+		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
+		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
+		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
+		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
+	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
+		   SCpnt->device->use_10_for_rw) {
+		if (this_count > 0xffff)
+			this_count = 0xffff;
+
+		SCpnt->cmnd[0] += READ_10 - READ_6;
+		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
+		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
+		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
+		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
+		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
+		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
+	} else {
+		if (this_count > 0xff)
+			this_count = 0xff;
+
+		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
+		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
+		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[4] = (unsigned char) this_count;
+		SCpnt->cmnd[5] = 0;
+	}
+	SCpnt->request_bufflen = SCpnt->bufflen =
+			this_count * sdp->sector_size;
+
+	/*
+	 * We shouldn't disconnect in the middle of a sector, so with a dumb
+	 * host adapter, it's safe to assume that we can at least transfer
+	 * this many bytes between each connect / disconnect.
+	 */
+	SCpnt->transfersize = sdp->sector_size;
+	SCpnt->underflow = this_count << 9;
+	SCpnt->allowed = SD_MAX_RETRIES;
+
+queue:
+	SCpnt->timeout_per_command = timeout;
+
+	/*
+	 * This is the completion routine we use.  This is matched in terms
+	 * of capability to this function.
+	 */
+	SCpnt->done = sd_rw_intr;
+
+	/*
+	 * This indicates that the command is ready from our end to be
+	 * queued.
+	 */
+	return 1;
+}
+
+/**
+ *	sd_open - open a scsi disk device
+ *	@inode: only i_rdev member may be used
+ *	@filp: only f_mode and f_flags may be used
+ *
+ *	Returns 0 if successful. Returns a negated errno value in case 
+ *	of error.
+ *
+ *	Note: This can be called from a user context (e.g. fsck(1) )
+ *	or from within the kernel (e.g. as a result of a mount(1) ).
+ *	In the latter case @inode and @filp carry an abridged amount
+ *	of information as noted above.
+ **/
+static int sd_open(struct inode *inode, struct file *filp)
+{
+	struct gendisk *disk = inode->i_bdev->bd_disk;
+	struct scsi_disk *sdkp;
+	struct scsi_device *sdev;
+	int retval;
+
+	if (!(sdkp = scsi_disk_get(disk)))
+		return -ENXIO;
+
+
+	SCSI_LOG_HLQUEUE(3, printk("sd_open: disk=%s\n", disk->disk_name));
+
+	sdev = sdkp->device;
+
+	/*
+	 * If the device is in error recovery, wait until it is done.
+	 * If the device is offline, then disallow any access to it.
+	 */
+	retval = -ENXIO;
+	if (!scsi_block_when_processing_errors(sdev))
+		goto error_out;
+
+	if (sdev->removable || sdkp->write_prot)
+		check_disk_change(inode->i_bdev);
+
+	/*
+	 * If the drive is empty, just let the open fail.
+	 */
+	retval = -ENOMEDIUM;
+	if (sdev->removable && !sdkp->media_present &&
+	    !(filp->f_flags & O_NDELAY))
+		goto error_out;
+
+	/*
+	 * If the device has the write protect tab set, have the open fail
+	 * if the user expects to be able to write to the thing.
+	 */
+	retval = -EROFS;
+	if (sdkp->write_prot && (filp->f_mode & FMODE_WRITE))
+		goto error_out;
+
+	/*
+	 * It is possible that the disk changing stuff resulted in
+	 * the device being taken offline.  If this is the case,
+	 * report this to the user, and don't pretend that the
+	 * open actually succeeded.
+	 */
+	retval = -ENXIO;
+	if (!scsi_device_online(sdev))
+		goto error_out;
+
+	if (!sdkp->openers++ && sdev->removable) {
+		if (scsi_block_when_processing_errors(sdev))
+			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
+	}
+
+	return 0;
+
+error_out:
+	scsi_disk_put(sdkp);
+	return retval;	
+}
+
+/**
+ *	sd_release - invoked when the (last) close(2) is called on this
+ *	scsi disk.
+ *	@inode: only i_rdev member may be used
+ *	@filp: only f_mode and f_flags may be used
+ *
+ *	Returns 0. 
+ *
+ *	Note: may block (uninterruptible) if error recovery is underway
+ *	on this disk.
+ **/
+static int sd_release(struct inode *inode, struct file *filp)
+{
+	struct gendisk *disk = inode->i_bdev->bd_disk;
+	struct scsi_disk *sdkp = scsi_disk(disk);
+	struct scsi_device *sdev = sdkp->device;
+
+	SCSI_LOG_HLQUEUE(3, printk("sd_release: disk=%s\n", disk->disk_name));
+
+	if (!--sdkp->openers && sdev->removable) {
+		if (scsi_block_when_processing_errors(sdev))
+			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
+	}
+
+	/*
+	 * XXX and what if there are packets in flight and this close()
+	 * XXX is followed by a "rmmod sd_mod"?
+	 */
+	scsi_disk_put(sdkp);
+	return 0;
+}
+
+static int sd_hdio_getgeo(struct block_device *bdev, struct hd_geometry __user *loc)
+{
+	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
+	struct scsi_device *sdp = sdkp->device;
+	struct Scsi_Host *host = sdp->host;
+	int diskinfo[4];
+
+	/* default to most commonly used values */
+        diskinfo[0] = 0x40;	/* 1 << 6 */
+       	diskinfo[1] = 0x20;	/* 1 << 5 */
+       	diskinfo[2] = sdkp->capacity >> 11;
+	
+	/* override with calculated, extended default, or driver values */
+	if (host->hostt->bios_param)
+		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
+	else
+		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);
+
+	if (put_user(diskinfo[0], &loc->heads))
+		return -EFAULT;
+	if (put_user(diskinfo[1], &loc->sectors))
+		return -EFAULT;
+	if (put_user(diskinfo[2], &loc->cylinders))
+		return -EFAULT;
+	if (put_user((unsigned)get_start_sect(bdev),
+	             (unsigned long __user *)&loc->start))
+		return -EFAULT;
+	return 0;
+}
+
+/**
+ *	sd_ioctl - process an ioctl
+ *	@inode: only i_rdev/i_bdev members may be used
+ *	@filp: only f_mode and f_flags may be used
+ *	@cmd: ioctl command number
+ *	@arg: this is third argument given to ioctl(2) system call.
+ *	Often contains a pointer.
+ *
+ *	Returns 0 if successful (some ioctls return postive numbers on
+ *	success as well). Returns a negated errno value in case of error.
+ *
+ *	Note: most ioctls are forward onto the block subsystem or further
+ *	down in the scsi subsytem.
+ **/
+static int sd_ioctl(struct inode * inode, struct file * filp, 
+		    unsigned int cmd, unsigned long arg)
+{
+	struct block_device *bdev = inode->i_bdev;
+	struct gendisk *disk = bdev->bd_disk;
+	struct scsi_device *sdp = scsi_disk(disk)->device;
+	void __user *p = (void __user *)arg;
+	int error;
+    
+	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
+						disk->disk_name, cmd));
+
+	/*
+	 * If we are in the middle of error recovery, don't let anyone
+	 * else try and use this device.  Also, if error recovery fails, it
+	 * may try and take the device offline, in which case all further
+	 * access to the device is prohibited.
+	 */
+	error = scsi_nonblockable_ioctl(sdp, cmd, p, filp);
+	if (!scsi_block_when_processing_errors(sdp) || !error)
+		return error;
+
+	if (cmd == HDIO_GETGEO) {
+		if (!arg)
+			return -EINVAL;
+		return sd_hdio_getgeo(bdev, p);
+	}
+
+	/*
+	 * Send SCSI addressing ioctls directly to mid level, send other
+	 * ioctls to block level and then onto mid level if they can't be
+	 * resolved.
+	 */
+	switch (cmd) {
+		case SCSI_IOCTL_GET_IDLUN:
+		case SCSI_IOCTL_GET_BUS_NUMBER:
+			return scsi_ioctl(sdp, cmd, p);
+		default:
+			error = scsi_cmd_ioctl(filp, disk, cmd, p);
+			if (error != -ENOTTY)
+				return error;
+	}
+	return scsi_ioctl(sdp, cmd, p);
+}
+
+static void set_media_not_present(struct scsi_disk *sdkp)
+{
+	sdkp->media_present = 0;
+	sdkp->capacity = 0;
+	sdkp->device->changed = 1;
+}
+
+/**
+ *	sd_media_changed - check if our medium changed
+ *	@disk: kernel device descriptor 
+ *
+ *	Returns 0 if not applicable or no change; 1 if change
+ *
+ *	Note: this function is invoked from the block subsystem.
+ **/
+static int sd_media_changed(struct gendisk *disk)
+{
+	struct scsi_disk *sdkp = scsi_disk(disk);
+	struct scsi_device *sdp = sdkp->device;
+	int retval;
+
+	SCSI_LOG_HLQUEUE(3, printk("sd_media_changed: disk=%s\n",
+						disk->disk_name));
+
+	if (!sdp->removable)
+		return 0;
+
+	/*
+	 * If the device is offline, don't send any commands - just pretend as
+	 * if the command failed.  If the device ever comes back online, we
+	 * can deal with it then.  It is only because of unrecoverable errors
+	 * that we would ever take a device offline in the first place.
+	 */
+	if (!scsi_device_online(sdp))
+		goto not_present;
+
+	/*
+	 * Using TEST_UNIT_READY enables differentiation between drive with
+	 * no cartridge loaded - NOT READY, drive with changed cartridge -
+	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
+	 *
+	 * Drives that auto spin down. eg iomega jaz 1G, will be started
+	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
+	 * sd_revalidate() is called.
+	 */
+	retval = -ENODEV;
+	if (scsi_block_when_processing_errors(sdp))
+		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);
+
+	/*
+	 * Unable to test, unit probably not ready.   This usually
+	 * means there is no disc in the drive.  Mark as changed,
+	 * and we will figure it out later once the drive is
+	 * available again.
+	 */
+	if (retval)
+		 goto not_present;
+
+	/*
+	 * For removable scsi disk we have to recognise the presence
+	 * of a disk in the drive. This is kept in the struct scsi_disk
+	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
+	 */
+	sdkp->media_present = 1;
+
+	retval = sdp->changed;
+	sdp->changed = 0;
+
+	return retval;
+
+not_present:
+	set_media_not_present(sdkp);
+	return 1;
+}
+
+static int sd_sync_cache(struct scsi_device *sdp)
+{
+	struct scsi_request *sreq;
+	int retries, res;
+
+	if (!scsi_device_online(sdp))
+		return -ENODEV;
+
+	sreq = scsi_allocate_request(sdp, GFP_KERNEL);
+	if (!sreq) {
+		printk("FAILED\n  No memory for request\n");
+		return -ENOMEM;
+	}
+
+	sreq->sr_data_direction = DMA_NONE;
+	for (retries = 3; retries > 0; --retries) {
+		unsigned char cmd[10] = { 0 };
+
+		cmd[0] = SYNCHRONIZE_CACHE;
+		/*
+		 * Leave the rest of the command zero to indicate
+		 * flush everything.
+		 */
+		scsi_wait_req(sreq, cmd, NULL, 0, SD_TIMEOUT, SD_MAX_RETRIES);
+		if (sreq->sr_result == 0)
+			break;
+	}
+
+	res = sreq->sr_result;
+	if (res) {
+		printk(KERN_WARNING "FAILED\n  status = %x, message = %02x, "
+				    "host = %d, driver = %02x\n  ",
+				    status_byte(res), msg_byte(res),
+				    host_byte(res), driver_byte(res));
+			if (driver_byte(res) & DRIVER_SENSE)
+				scsi_print_req_sense("sd", sreq);
+	}
+
+	scsi_release_request(sreq);
+	return res;
+}
+
+static int sd_issue_flush(struct device *dev, sector_t *error_sector)
+{
+	struct scsi_device *sdp = to_scsi_device(dev);
+	struct scsi_disk *sdkp = dev_get_drvdata(dev);
+
+	if (!sdkp)
+               return -ENODEV;
+
+	if (!sdkp->WCE)
+		return 0;
+
+	return sd_sync_cache(sdp);
+}
+
+static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
+{
+	struct request *rq = flush_rq->end_io_data;
+	struct scsi_cmnd *cmd = rq->special;
+	unsigned int bytes = rq->hard_nr_sectors << 9;
+
+	if (!flush_rq->errors) {
+		spin_unlock(q->queue_lock);
+		scsi_io_completion(cmd, bytes, 0);
+		spin_lock(q->queue_lock);
+	} else if (blk_barrier_postflush(rq)) {
+		spin_unlock(q->queue_lock);
+		scsi_io_completion(cmd, 0, bytes);
+		spin_lock(q->queue_lock);
+	} else {
+		/*
+		 * force journal abort of barriers
+		 */
+		end_that_request_first(rq, -EOPNOTSUPP, rq->hard_nr_sectors);
+		end_that_request_last(rq);
+	}
+}
+
+static int sd_prepare_flush(request_queue_t *q, struct request *rq)
+{
+	struct scsi_device *sdev = q->queuedata;
+	struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);
+
+	if (sdkp->WCE) {
+		memset(rq->cmd, 0, sizeof(rq->cmd));
+		rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
+		rq->timeout = SD_TIMEOUT;
+		rq->cmd[0] = SYNCHRONIZE_CACHE;
+		return 1;
+	}
+
+	return 0;
+}
+
+static void sd_rescan(struct device *dev)
+{
+	struct scsi_disk *sdkp = dev_get_drvdata(dev);
+	sd_revalidate_disk(sdkp->disk);
+}
+
+
+#ifdef CONFIG_COMPAT
+/* 
+ * This gets directly called from VFS. When the ioctl 
+ * is not recognized we go back to the other translation paths. 
+ */
+static long sd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
+	struct gendisk *disk = bdev->bd_disk;
+	struct scsi_device *sdev = scsi_disk(disk)->device;
+
+	/*
+	 * If we are in the middle of error recovery, don't let anyone
+	 * else try and use this device.  Also, if error recovery fails, it
+	 * may try and take the device offline, in which case all further
+	 * access to the device is prohibited.
+	 */
+	if (!scsi_block_when_processing_errors(sdev))
+		return -ENODEV;
+	       
+	if (sdev->host->hostt->compat_ioctl) {
+		int ret;
+
+		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
+
+		return ret;
+	}
+
+	/* 
+	 * Let the static ioctl translation table take care of it.
+	 */
+	return -ENOIOCTLCMD; 
+}
+#endif
+
+static struct block_device_operations sd_fops = {
+	.owner			= THIS_MODULE,
+	.open			= sd_open,
+	.release		= sd_release,
+	.ioctl			= sd_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl		= sd_compat_ioctl,
+#endif
+	.media_changed		= sd_media_changed,
+	.revalidate_disk	= sd_revalidate_disk,
+};
+
+/**
+ *	sd_rw_intr - bottom half handler: called when the lower level
+ *	driver has completed (successfully or otherwise) a scsi command.
+ *	@SCpnt: mid-level's per command structure.
+ *
+ *	Note: potentially run from within an ISR. Must not block.
+ **/
+static void sd_rw_intr(struct scsi_cmnd * SCpnt)
+{
+	int result = SCpnt->result;
+	int this_count = SCpnt->bufflen;
+	int good_bytes = (result == 0 ? this_count : 0);
+	sector_t block_sectors = 1;
+	u64 first_err_block;
+	sector_t error_sector;
+	struct scsi_sense_hdr sshdr;
+	int sense_valid = 0;
+	int sense_deferred = 0;
+	int info_valid;
+
+	if (result) {
+		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
+		if (sense_valid)
+			sense_deferred = scsi_sense_is_deferred(&sshdr);
+	}
+
+#ifdef CONFIG_SCSI_LOGGING
+	SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: %s: res=0x%x\n", 
+				SCpnt->request->rq_disk->disk_name, result));
+	if (sense_valid) {
+		SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: sb[respc,sk,asc,"
+				"ascq]=%x,%x,%x,%x\n", sshdr.response_code,
+				sshdr.sense_key, sshdr.asc, sshdr.ascq));
+	}
+#endif
+	/*
+	   Handle MEDIUM ERRORs that indicate partial success.  Since this is a
+	   relatively rare error condition, no care is taken to avoid
+	   unnecessary additional work such as memcpy's that could be avoided.
+	 */
+
+	/* 
+	 * If SG_IO from block layer then set good_bytes to stop retries;
+	 * else if errors, check them, and if necessary prepare for
+	 * (partial) retries.
+	 */
+	if (blk_pc_request(SCpnt->request))
+		good_bytes = this_count;
+	else if (driver_byte(result) != 0 &&
+		 sense_valid && !sense_deferred) {
+		switch (sshdr.sense_key) {
+		case MEDIUM_ERROR:
+			if (!blk_fs_request(SCpnt->request))
+				break;
+			info_valid = scsi_get_sense_info_fld(
+				SCpnt->sense_buffer, SCSI_SENSE_BUFFERSIZE,
+				&first_err_block);
+			/*
+			 * May want to warn and skip if following cast results
+			 * in actual truncation (if sector_t < 64 bits)
+			 */
+			error_sector = (sector_t)first_err_block;
+			if (SCpnt->request->bio != NULL)
+				block_sectors = bio_sectors(SCpnt->request->bio);
+			switch (SCpnt->device->sector_size) {
+			case 1024:
+				error_sector <<= 1;
+				if (block_sectors < 2)
+					block_sectors = 2;
+				break;
+			case 2048:
+				error_sector <<= 2;
+				if (block_sectors < 4)
+					block_sectors = 4;
+				break;
+			case 4096:
+				error_sector <<=3;
+				if (block_sectors < 8)
+					block_sectors = 8;
+				break;
+			case 256:
+				error_sector >>= 1;
+				break;
+			default:
+				break;
+			}
+
+			error_sector &= ~(block_sectors - 1);
+			good_bytes = (error_sector - SCpnt->request->sector) << 9;
+			if (good_bytes < 0 || good_bytes >= this_count)
+				good_bytes = 0;
+			break;
+
+		case RECOVERED_ERROR: /* an error occurred, but it recovered */
+		case NO_SENSE: /* LLDD got sense data */
+			/*
+			 * Inform the user, but make sure that it's not treated
+			 * as a hard error.
+			 */
+			scsi_print_sense("sd", SCpnt);
+			SCpnt->result = 0;
+			memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+			good_bytes = this_count;
+			break;
+
+		case ILLEGAL_REQUEST:
+			if (SCpnt->device->use_10_for_rw &&
+			    (SCpnt->cmnd[0] == READ_10 ||
+			     SCpnt->cmnd[0] == WRITE_10))
+				SCpnt->device->use_10_for_rw = 0;
+			if (SCpnt->device->use_10_for_ms &&
+			    (SCpnt->cmnd[0] == MODE_SENSE_10 ||
+			     SCpnt->cmnd[0] == MODE_SELECT_10))
+				SCpnt->device->use_10_for_ms = 0;
+			break;
+
+		default:
+			break;
+		}
+	}
+	/*
+	 * This calls the generic completion function, now that we know
+	 * how many actual sectors finished, and how many sectors we need
+	 * to say have failed.
+	 */
+	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
+}
+
+static int media_not_present(struct scsi_disk *sdkp, struct scsi_request *srp)
+{
+	struct scsi_sense_hdr sshdr;
+
+	if (!srp->sr_result)
+		return 0;
+	if (!(driver_byte(srp->sr_result) & DRIVER_SENSE))
+		return 0;
+	/* not invoked for commands that could return deferred errors */
+	if (scsi_request_normalize_sense(srp, &sshdr)) {
+		if (sshdr.sense_key != NOT_READY &&
+		    sshdr.sense_key != UNIT_ATTENTION)
+			return 0;
+		if (sshdr.asc != 0x3A) /* medium not present */
+			return 0;
+	}
+	set_media_not_present(sdkp);
+	return 1;
+}
+
+/*
+ * spinup disk - called only in sd_revalidate_disk()
+ */
+static void
+sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
+	       struct scsi_request *SRpnt, unsigned char *buffer) {
+	unsigned char cmd[10];
+	unsigned long spintime_value = 0;
+	int retries, spintime;
+	unsigned int the_result;
+	struct scsi_sense_hdr sshdr;
+	int sense_valid = 0;
+
+	spintime = 0;
+
+	/* Spin up drives, as required.  Only do this at boot time */
+	/* Spinup needs to be done for module loads too. */
+	do {
+		retries = 0;
+
+		do {
+			cmd[0] = TEST_UNIT_READY;
+			memset((void *) &cmd[1], 0, 9);
+
+			SRpnt->sr_cmd_len = 0;
+			memset(SRpnt->sr_sense_buffer, 0,
+			       SCSI_SENSE_BUFFERSIZE);
+			SRpnt->sr_data_direction = DMA_NONE;
+
+			scsi_wait_req (SRpnt, (void *) cmd, (void *) buffer,
+				       0/*512*/, SD_TIMEOUT, SD_MAX_RETRIES);
+
+			the_result = SRpnt->sr_result;
+			if (the_result)
+				sense_valid = scsi_request_normalize_sense(
+							SRpnt, &sshdr);
+			retries++;
+		} while (retries < 3 && 
+			 (!scsi_status_is_good(the_result) ||
+			  ((driver_byte(the_result) & DRIVER_SENSE) &&
+			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
+
+		/*
+		 * If the drive has indicated to us that it doesn't have
+		 * any media in it, don't bother with any of the rest of
+		 * this crap.
+		 */
+		if (media_not_present(sdkp, SRpnt))
+			return;
+
+		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
+			/* no sense, TUR either succeeded or failed
+			 * with a status error */
+			if(!spintime && !scsi_status_is_good(the_result))
+				printk(KERN_NOTICE "%s: Unit Not Ready, "
+				       "error = 0x%x\n", diskname, the_result);
+			break;
+		}
+					
+		/*
+		 * The device does not want the automatic start to be issued.
+		 */
+		if (sdkp->device->no_start_on_add) {
+			break;
+		}
+
+		/*
+		 * If manual intervention is required, or this is an
+		 * absent USB storage device, a spinup is meaningless.
+		 */
+		if (sense_valid &&
+		    sshdr.sense_key == NOT_READY &&
+		    sshdr.asc == 4 && sshdr.ascq == 3) {
+			break;		/* manual intervention required */
+
+		/*
+		 * Issue command to spin up drive when not ready
+		 */
+		} else if (sense_valid && sshdr.sense_key == NOT_READY) {
+			if (!spintime) {
+				printk(KERN_NOTICE "%s: Spinning up disk...",
+				       diskname);
+				cmd[0] = START_STOP;
+				cmd[1] = 1;	/* Return immediately */
+				memset((void *) &cmd[2], 0, 8);
+				cmd[4] = 1;	/* Start spin cycle */
+				SRpnt->sr_cmd_len = 0;
+				memset(SRpnt->sr_sense_buffer, 0,
+					SCSI_SENSE_BUFFERSIZE);
+
+				SRpnt->sr_data_direction = DMA_NONE;
+				scsi_wait_req(SRpnt, (void *)cmd, 
+					      (void *) buffer, 0/*512*/, 
+					      SD_TIMEOUT, SD_MAX_RETRIES);
+				spintime_value = jiffies;
+			}
+			spintime = 1;
+			/* Wait 1 second for next try */
+			msleep(1000);
+			printk(".");
+		} else {
+			/* we don't understand the sense code, so it's
+			 * probably pointless to loop */
+			if(!spintime) {
+				printk(KERN_NOTICE "%s: Unit Not Ready, "
+					"sense:\n", diskname);
+				scsi_print_req_sense("", SRpnt);
+			}
+			break;
+		}
+				
+	} while (spintime &&
+		 time_after(spintime_value + 100 * HZ, jiffies));
+
+	if (spintime) {
+		if (scsi_status_is_good(the_result))
+			printk("ready\n");
+		else
+			printk("not responding...\n");
+	}
+}
+
+/*
+ * read disk capacity
+ */
+static void
+sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
+		 struct scsi_request *SRpnt, unsigned char *buffer) {
+	unsigned char cmd[16];
+	struct scsi_device *sdp = sdkp->device;
+	int the_result, retries;
+	int sector_size = 0;
+	int longrc = 0;
+	struct scsi_sense_hdr sshdr;
+	int sense_val