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linux/drivers/scsi/sd.c
Chen, Kenneth W 7fce2cf62e [SCSI] Redundant this_count check in sd_init_command() 
I was going over the scsi I/O submit path, when sd_init_command
construct the scsi command, this_count is already checked in the
previous else if clause.  Why does it need to check it again in
the last else block?

Patch to delete the spurious check.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-07-14 11:25:17 -04:00

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/*
* 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 {
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_valid = 0;
repeat:
retries = 3;
do {
if (longrc) {
memset((void *) cmd, 0, 16);
cmd[0] = SERVICE_ACTION_IN;
cmd[1] = SAI_READ_CAPACITY_16;
cmd[13] = 12;
memset((void *) buffer, 0, 12);
} else {
cmd[0] = READ_CAPACITY;
memset((void *) &cmd[1], 0, 9);
memset((void *) buffer, 0, 8);
}
SRpnt->sr_cmd_len = 0;
memset(SRpnt->sr_sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
SRpnt->sr_data_direction = DMA_FROM_DEVICE;
scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
longrc ? 12 : 8, SD_TIMEOUT, SD_MAX_RETRIES);
if (media_not_present(sdkp, SRpnt))
return;
the_result = SRpnt->sr_result;
if (the_result)
sense_valid = scsi_request_normalize_sense(SRpnt,
&sshdr);
retries--;
} while (the_result && retries);
if (the_result && !longrc) {
printk(KERN_NOTICE "%s : READ CAPACITY failed.\n"
"%s : status=%x, message=%02x, host=%d, driver=%02x \n",
diskname, diskname,
status_byte(the_result),
msg_byte(the_result),
host_byte(the_result),
driver_byte(the_result));
if (driver_byte(the_result) & DRIVER_SENSE)
scsi_print_req_sense("sd", SRpnt);
else
printk("%s : sense not available. \n", diskname);
/* Set dirty bit for removable devices if not ready -
* sometimes drives will not report this properly. */
if (sdp->removable &&
sense_valid && sshdr.sense_key == NOT_READY)
sdp->changed = 1;
/* Either no media are present but the drive didn't tell us,
or they are present but the read capacity command fails */
/* sdkp->media_present = 0; -- not always correct */
sdkp->capacity = 0x200000; /* 1 GB - random */
return;
} else if (the_result && longrc) {
/* READ CAPACITY(16) has been failed */
printk(KERN_NOTICE "%s : READ CAPACITY(16) failed.\n"
"%s : status=%x, message=%02x, host=%d, driver=%02x \n",
diskname, diskname,
status_byte(the_result),
msg_byte(the_result),
host_byte(the_result),
driver_byte(the_result));
printk(KERN_NOTICE "%s : use 0xffffffff as device size\n",
diskname);
sdkp->capacity = 1 + (sector_t) 0xffffffff;
goto got_data;
}
if (!longrc) {
sector_size = (buffer[4] << 24) |
(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
if (buffer[0] == 0xff && buffer[1] == 0xff &&
buffer[2] == 0xff && buffer[3] == 0xff) {
if(sizeof(sdkp->capacity) > 4) {
printk(KERN_NOTICE "%s : very big device. try to use"
" READ CAPACITY(16).\n", diskname);
longrc = 1;
goto repeat;
}
printk(KERN_ERR "%s: too big for this kernel. Use a "
"kernel compiled with support for large block "
"devices.\n", diskname);
sdkp->capacity = 0;
goto got_data;
}
sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
(buffer[1] << 16) |
(buffer[2] << 8) |
buffer[3]);
} else {
sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
((u64)buffer[1] << 48) |
((u64)buffer[2] << 40) |
((u64)buffer[3] << 32) |
((sector_t)buffer[4] << 24) |
((sector_t)buffer[5] << 16) |
((sector_t)buffer[6] << 8) |
(sector_t)buffer[7]);
sector_size = (buffer[8] << 24) |
(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
}
/* Some devices return the total number of sectors, not the
* highest sector number. Make the necessary adjustment. */
if (sdp->fix_capacity)
--sdkp->capacity;
got_data:
if (sector_size == 0) {
sector_size = 512;
printk(KERN_NOTICE "%s : sector size 0 reported, "
"assuming 512.\n", diskname);
}
if (sector_size != 512 &&
sector_size != 1024 &&
sector_size != 2048 &&
sector_size != 4096 &&
sector_size != 256) {
printk(KERN_NOTICE "%s : unsupported sector size "
"%d.\n", diskname, sector_size);
/*
* The user might want to re-format the drive with
* a supported sectorsize. Once this happens, it
* would be relatively trivial to set the thing up.
* For this reason, we leave the thing in the table.
*/
sdkp->capacity = 0;
/*
* set a bogus sector size so the normal read/write
* logic in the block layer will eventually refuse any
* request on this device without tripping over power
* of two sector size assumptions
*/
sector_size = 512;
}
{
/*
* The msdos fs needs to know the hardware sector size
* So I have created this table. See ll_rw_blk.c
* Jacques Gelinas (Jacques@solucorp.qc.ca)
*/
int hard_sector = sector_size;
sector_t sz = sdkp->capacity * (hard_sector/256);
request_queue_t *queue = sdp->request_queue;
sector_t mb;
blk_queue_hardsect_size(queue, hard_sector);
/* avoid 64-bit division on 32-bit platforms */
mb = sz >> 1;
sector_div(sz, 1250);
mb -= sz - 974;
sector_div(mb, 1950);
printk(KERN_NOTICE "SCSI device %s: "
"%llu %d-byte hdwr sectors (%llu MB)\n",
diskname, (unsigned long long)sdkp->capacity,
hard_sector, (unsigned long long)mb);
}
/* Rescale capacity to 512-byte units */
if (sector_size == 4096)
sdkp->capacity <<= 3;
else if (sector_size == 2048)
sdkp->capacity <<= 2;
else if (sector_size == 1024)
sdkp->capacity <<= 1;
else if (sector_size == 256)
sdkp->capacity >>= 1;
sdkp->device->sector_size = sector_size;
}
/* called with buffer of length 512 */
static inline int
sd_do_mode_sense(struct scsi_request *SRpnt, int dbd, int modepage,
unsigned char *buffer, int len, struct scsi_mode_data *data)
{
return __scsi_mode_sense(SRpnt, dbd, modepage, buffer, len,
SD_TIMEOUT, SD_MAX_RETRIES, data);
}
/*
* read write protect setting, if possible - called only in sd_revalidate_disk()
* called with buffer of length 512
*/
static void
sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
struct scsi_request *SRpnt, unsigned char *buffer) {
int res;
struct scsi_mode_data data;
set_disk_ro(sdkp->disk, 0);
if (sdkp->device->skip_ms_page_3f) {
printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
return;
}
if (sdkp->device->use_192_bytes_for_3f) {
res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 192, &data);
} else {
/*
* First attempt: ask for all pages (0x3F), but only 4 bytes.
* We have to start carefully: some devices hang if we ask
* for more than is available.
*/
res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 4, &data);
/*
* Second attempt: ask for page 0 When only page 0 is
* implemented, a request for page 3F may return Sense Key
* 5: Illegal Request, Sense Code 24: Invalid field in
* CDB.
*/
if (!scsi_status_is_good(res))
res = sd_do_mode_sense(SRpnt, 0, 0, buffer, 4, &data);
/*
* Third attempt: ask 255 bytes, as we did earlier.
*/
if (!scsi_status_is_good(res))
res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 255,
&data);
}
if (!scsi_status_is_good(res)) {
printk(KERN_WARNING
"%s: test WP failed, assume Write Enabled\n", diskname);
} else {
sdkp->write_prot = ((data.device_specific & 0x80) != 0);
set_disk_ro(sdkp->disk, sdkp->write_prot);
printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname,
sdkp->write_prot ? "on" : "off");
printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n",
diskname, buffer[0], buffer[1], buffer[2], buffer[3]);
}
}
/*
* sd_read_cache_type - called only from sd_revalidate_disk()
* called with buffer of length 512
*/
static void
sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
struct scsi_request *SRpnt, unsigned char *buffer)
{
int len = 0, res;
int dbd;
int modepage;
struct scsi_mode_data data;
struct scsi_sense_hdr sshdr;
if (sdkp->device->skip_ms_page_8)
goto defaults;
if (sdkp->device->type == TYPE_RBC) {
modepage = 6;
dbd = 8;
} else {
modepage = 8;
dbd = 0;
}
/* cautiously ask */
res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, 4, &data);
if (!scsi_status_is_good(res))
goto bad_sense;
/* that went OK, now ask for the proper length */
len = data.length;
/*
* We're only interested in the first three bytes, actually.
* But the data cache page is defined for the first 20.
*/
if (len < 3)
goto bad_sense;
if (len > 20)
len = 20;
/* Take headers and block descriptors into account */
len += data.header_length + data.block_descriptor_length;
/* Get the data */
res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, len, &data);
if (scsi_status_is_good(res)) {
const char *types[] = {
"write through", "none", "write back",
"write back, no read (daft)"
};
int ct = 0;
int offset = data.header_length + data.block_descriptor_length;
if ((buffer[offset] & 0x3f) != modepage) {
printk(KERN_ERR "%s: got wrong page\n", diskname);
goto defaults;
}
if (modepage == 8) {
sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
} else {
sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
sdkp->RCD = 0;
}
ct = sdkp->RCD + 2*sdkp->WCE;
printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
diskname, types[ct]);
return;
}
bad_sense:
if (scsi_request_normalize_sense(SRpnt, &sshdr) &&
sshdr.sense_key == ILLEGAL_REQUEST &&
sshdr.asc == 0x24 && sshdr.ascq == 0x0)
printk(KERN_NOTICE "%s: cache data unavailable\n",
diskname); /* Invalid field in CDB */
else
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;
sdkp->RCD = 0;
}
/**
* sd_revalidate_disk - called the first time a new disk is seen,
* performs disk spin up, read_capacity, etc.
* @disk: struct gendisk we care about
**/
static int sd_revalidate_disk(struct gendisk *disk)
{
struct scsi_disk *sdkp = scsi_disk(disk);
struct scsi_device *sdp = sdkp->device;
struct scsi_request *sreq;
unsigned char *buffer;
SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));
/*
* If the device is offline, don't try and read capacity or any
* of the other niceties.
*/
if (!scsi_device_online(sdp))
goto out;
sreq = scsi_allocate_request(sdp, GFP_KERNEL);
if (!sreq) {
printk(KERN_WARNING "(sd_revalidate_disk:) Request allocation "
"failure.\n");
goto out;
}
buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA);
if (!buffer) {
printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
"failure.\n");
goto out_release_request;
}
/* defaults, until the device tells us otherwise */
sdp->sector_size = 512;
sdkp->capacity = 0;
sdkp->media_present = 1;
sdkp->write_prot = 0;
sdkp->WCE = 0;
sdkp->RCD = 0;
sd_spinup_disk(sdkp, disk->disk_name, sreq, buffer);
/*
* Without media there is no reason to ask; moreover, some devices
* react badly if we do.
*/
if (sdkp->media_present) {
sd_read_capacity(sdkp, disk->disk_name, sreq, buffer);
if (sdp->removable)
sd_read_write_protect_flag(sdkp, disk->disk_name,
sreq, buffer);
sd_read_cache_type(sdkp, disk->disk_name, sreq, buffer);
}
set_capacity(disk, sdkp->capacity);
kfree(buffer);
out_release_request:
scsi_release_request(sreq);
out:
return 0;
}
/**
* sd_probe - called during driver initialization and whenever a
* new scsi device is attached to the system. It is called once
* for each scsi device (not just disks) present.
* @dev: pointer to device object
*
* Returns 0 if successful (or not interested in this scsi device
* (e.g. scanner)); 1 when there is an error.
*
* Note: this function is invoked from the scsi mid-level.
* This function sets up the mapping between a given
* <host,channel,id,lun> (found in sdp) and new device name
* (e.g. /dev/sda). More precisely it is the block device major
* and minor number that is chosen here.
*
* Assume sd_attach is not re-entrant (for time being)
* Also think about sd_attach() and sd_remove() running coincidentally.
**/
static int sd_probe(struct device *dev)
{
struct scsi_device *sdp = to_scsi_device(dev);
struct scsi_disk *sdkp;
struct gendisk *gd;
u32 index;
int error;
error = -ENODEV;
if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
goto out;
SCSI_LOG_HLQUEUE(3, printk("sd_attach: scsi device: <%d,%d,%d,%d>\n",
sdp->host->host_no, sdp->channel, sdp->id, sdp->lun));
error = -ENOMEM;
sdkp = kmalloc(sizeof(*sdkp), GFP_KERNEL);
if (!sdkp)
goto out;
memset (sdkp, 0, sizeof(*sdkp));
kref_init(&sdkp->kref);
gd = alloc_disk(16);
if (!gd)
goto out_free;
if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))
goto out_put;
spin_lock(&sd_index_lock);
error = idr_get_new(&sd_index_idr, NULL, &index);
spin_unlock(&sd_index_lock);
if (index >= SD_MAX_DISKS)
error = -EBUSY;
if (error)
goto out_put;
sdkp->device = sdp;
sdkp->driver = &sd_template;
sdkp->disk = gd;
sdkp->index = index;
sdkp->openers = 0;
if (!sdp->timeout) {
if (sdp->type != TYPE_MOD)
sdp->timeout = SD_TIMEOUT;
else
sdp->timeout = SD_MOD_TIMEOUT;
}
gd->major = sd_major((index & 0xf0) >> 4);
gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
gd->minors = 16;
gd->fops = &sd_fops;
if (index < 26) {
sprintf(gd->disk_name, "sd%c", 'a' + index % 26);
} else if (index < (26 + 1) * 26) {
sprintf(gd->disk_name, "sd%c%c",
'a' + index / 26 - 1,'a' + index % 26);
} else {
const unsigned int m1 = (index / 26 - 1) / 26 - 1;
const unsigned int m2 = (index / 26 - 1) % 26;
const unsigned int m3 = index % 26;
sprintf(gd->disk_name, "sd%c%c%c",
'a' + m1, 'a' + m2, 'a' + m3);
}
strcpy(gd->devfs_name, sdp->devfs_name);
gd->private_data = &sdkp->driver;
sd_revalidate_disk(gd);
gd->driverfs_dev = &sdp->sdev_gendev;
gd->flags = GENHD_FL_DRIVERFS;
if (sdp->removable)
gd->flags |= GENHD_FL_REMOVABLE;
gd->queue = sdkp->device->request_queue;
dev_set_drvdata(dev, sdkp);
add_disk(gd);
printk(KERN_NOTICE "Attached scsi %sdisk %s at scsi%d, channel %d, "
"id %d, lun %d\n", sdp->removable ? "removable " : "",
gd->disk_name, sdp->host->host_no, sdp->channel,
sdp->id, sdp->lun);
return 0;
out_put:
put_disk(gd);
out_free:
kfree(sdkp);
out:
return error;
}
/**
* sd_remove - called whenever a scsi disk (previously recognized by
* sd_probe) is detached from the system. It is called (potentially
* multiple times) during sd module unload.
* @sdp: pointer to mid level scsi device object
*
* Note: this function is invoked from the scsi mid-level.
* This function potentially frees up a device name (e.g. /dev/sdc)
* that could be re-used by a subsequent sd_probe().
* This function is not called when the built-in sd driver is "exit-ed".
**/
static int sd_remove(struct device *dev)
{
struct scsi_disk *sdkp = dev_get_drvdata(dev);
del_gendisk(sdkp->disk);
sd_shutdown(dev);
down(&sd_ref_sem);
kref_put(&sdkp->kref, scsi_disk_release);
up(&sd_ref_sem);
return 0;
}
/**
* scsi_disk_release - Called to free the scsi_disk structure
* @kref: pointer to embedded kref
*
* sd_ref_sem must be held entering this routine. Because it is
* called on last put, you should always use the scsi_disk_get()
* scsi_disk_put() helpers which manipulate the semaphore directly
* and never do a direct kref_put().
**/
static void scsi_disk_release(struct kref *kref)
{
struct scsi_disk *sdkp = to_scsi_disk(kref);
struct gendisk *disk = sdkp->disk;
spin_lock(&sd_index_lock);
idr_remove(&sd_index_idr, sdkp->index);
spin_unlock(&sd_index_lock);
disk->private_data = NULL;
put_disk(disk);
kfree(sdkp);
}
/*
* Send a SYNCHRONIZE CACHE instruction down to the device through
* the normal SCSI command structure. Wait for the command to
* complete.
*/
static void sd_shutdown(struct device *dev)
{
struct scsi_device *sdp = to_scsi_device(dev);
struct scsi_disk *sdkp = dev_get_drvdata(dev);
if (!sdkp)
return; /* this can happen */
if (!sdkp->WCE)
return;
printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
sdkp->disk->disk_name);
sd_sync_cache(sdp);
}
/**
* init_sd - entry point for this driver (both when built in or when
* a module).
*
* Note: this function registers this driver with the scsi mid-level.
**/
static int __init init_sd(void)
{
int majors = 0, i;
SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
for (i = 0; i < SD_MAJORS; i++)
if (register_blkdev(sd_major(i), "sd") == 0)
majors++;
if (!majors)
return -ENODEV;
return scsi_register_driver(&sd_template.gendrv);
}
/**
* exit_sd - exit point for this driver (when it is a module).
*
* Note: this function unregisters this driver from the scsi mid-level.
**/
static void __exit exit_sd(void)
{
int i;
SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
scsi_unregister_driver(&sd_template.gendrv);
for (i = 0; i < SD_MAJORS; i++)
unregister_blkdev(sd_major(i), "sd");
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eric Youngdale");
MODULE_DESCRIPTION("SCSI disk (sd) driver");
module_init(init_sd);
module_exit(exit_sd);
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