linux-sg2042/drivers/scsi/scsicam.c

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/*
* scsicam.c - SCSI CAM support functions, use for HDIO_GETGEO, etc.
*
* Copyright 1993, 1994 Drew Eckhardt
* Visionary Computing
* (Unix and Linux consulting and custom programming)
* drew@Colorado.EDU
* +1 (303) 786-7975
*
* For more information, please consult the SCSI-CAM draft.
*/
#include <linux/module.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <asm/unaligned.h>
#include <scsi/scsicam.h>
static int setsize(unsigned long capacity, unsigned int *cyls, unsigned int *hds,
unsigned int *secs);
/**
* scsi_bios_ptable - Read PC partition table out of first sector of device.
* @dev: from this device
*
* Description: Reads the first sector from the device and returns %0x42 bytes
* starting at offset %0x1be.
* Returns: partition table in kmalloc(GFP_KERNEL) memory, or NULL on error.
*/
unsigned char *scsi_bios_ptable(struct block_device *dev)
{
unsigned char *res = kmalloc(66, GFP_KERNEL);
if (res) {
struct block_device *bdev = dev->bd_contains;
Sector sect;
void *data = read_dev_sector(bdev, 0, &sect);
if (data) {
memcpy(res, data + 0x1be, 66);
put_dev_sector(sect);
} else {
kfree(res);
res = NULL;
}
}
return res;
}
EXPORT_SYMBOL(scsi_bios_ptable);
/**
* scsicam_bios_param - Determine geometry of a disk in cylinders/heads/sectors.
* @bdev: which device
* @capacity: size of the disk in sectors
* @ip: return value: ip[0]=heads, ip[1]=sectors, ip[2]=cylinders
*
* Description : determine the BIOS mapping/geometry used for a drive in a
* SCSI-CAM system, storing the results in ip as required
* by the HDIO_GETGEO ioctl().
*
* Returns : -1 on failure, 0 on success.
*/
int scsicam_bios_param(struct block_device *bdev, sector_t capacity, int *ip)
{
unsigned char *p;
u64 capacity64 = capacity; /* Suppress gcc warning */
int ret;
p = scsi_bios_ptable(bdev);
if (!p)
return -1;
/* try to infer mapping from partition table */
ret = scsi_partsize(p, (unsigned long)capacity, (unsigned int *)ip + 2,
(unsigned int *)ip + 0, (unsigned int *)ip + 1);
kfree(p);
if (ret == -1 && capacity64 < (1ULL << 32)) {
/* pick some standard mapping with at most 1024 cylinders,
and at most 62 sectors per track - this works up to
7905 MB */
ret = setsize((unsigned long)capacity, (unsigned int *)ip + 2,
(unsigned int *)ip + 0, (unsigned int *)ip + 1);
}
/* if something went wrong, then apparently we have to return
a geometry with more than 1024 cylinders */
if (ret || ip[0] > 255 || ip[1] > 63) {
if ((capacity >> 11) > 65534) {
ip[0] = 255;
ip[1] = 63;
} else {
ip[0] = 64;
ip[1] = 32;
}
if (capacity > 65535*63*255)
ip[2] = 65535;
else
ip[2] = (unsigned long)capacity / (ip[0] * ip[1]);
}
return 0;
}
EXPORT_SYMBOL(scsicam_bios_param);
/**
* scsi_partsize - Parse cylinders/heads/sectors from PC partition table
* @buf: partition table, see scsi_bios_ptable()
* @capacity: size of the disk in sectors
* @cyls: put cylinders here
* @hds: put heads here
* @secs: put sectors here
*
* Description: determine the BIOS mapping/geometry used to create the partition
* table, storing the results in *cyls, *hds, and *secs
*
* Returns: -1 on failure, 0 on success.
*/
int scsi_partsize(unsigned char *buf, unsigned long capacity,
unsigned int *cyls, unsigned int *hds, unsigned int *secs)
{
struct partition *p = (struct partition *)buf, *largest = NULL;
int i, largest_cyl;
int cyl, ext_cyl, end_head, end_cyl, end_sector;
unsigned int logical_end, physical_end, ext_physical_end;
if (*(unsigned short *) (buf + 64) == 0xAA55) {
for (largest_cyl = -1, i = 0; i < 4; ++i, ++p) {
if (!p->sys_ind)
continue;
#ifdef DEBUG
printk("scsicam_bios_param : partition %d has system \n",
i);
#endif
cyl = p->cyl + ((p->sector & 0xc0) << 2);
if (cyl > largest_cyl) {
largest_cyl = cyl;
largest = p;
}
}
}
if (largest) {
end_cyl = largest->end_cyl + ((largest->end_sector & 0xc0) << 2);
end_head = largest->end_head;
end_sector = largest->end_sector & 0x3f;
if (end_head + 1 == 0 || end_sector == 0)
return -1;
#ifdef DEBUG
printk("scsicam_bios_param : end at h = %d, c = %d, s = %d\n",
end_head, end_cyl, end_sector);
#endif
physical_end = end_cyl * (end_head + 1) * end_sector +
end_head * end_sector + end_sector;
/* This is the actual _sector_ number at the end */
logical_end = get_unaligned(&largest->start_sect)
+ get_unaligned(&largest->nr_sects);
/* This is for >1023 cylinders */
ext_cyl = (logical_end - (end_head * end_sector + end_sector))
/ (end_head + 1) / end_sector;
ext_physical_end = ext_cyl * (end_head + 1) * end_sector +
end_head * end_sector + end_sector;
#ifdef DEBUG
printk("scsicam_bios_param : logical_end=%d physical_end=%d ext_physical_end=%d ext_cyl=%d\n"
,logical_end, physical_end, ext_physical_end, ext_cyl);
#endif
if ((logical_end == physical_end) ||
(end_cyl == 1023 && ext_physical_end == logical_end)) {
*secs = end_sector;
*hds = end_head + 1;
*cyls = capacity / ((end_head + 1) * end_sector);
return 0;
}
#ifdef DEBUG
printk("scsicam_bios_param : logical (%u) != physical (%u)\n",
logical_end, physical_end);
#endif
}
return -1;
}
EXPORT_SYMBOL(scsi_partsize);
/*
* Function : static int setsize(unsigned long capacity,unsigned int *cyls,
* unsigned int *hds, unsigned int *secs);
*
* Purpose : to determine a near-optimal int 0x13 mapping for a
* SCSI disk in terms of lost space of size capacity, storing
* the results in *cyls, *hds, and *secs.
*
* Returns : -1 on failure, 0 on success.
*
* Extracted from
*
* WORKING X3T9.2
* DRAFT 792D
* see http://www.t10.org/ftp/t10/drafts/cam/cam-r12b.pdf
*
* Revision 6
* 10-MAR-94
* Information technology -
* SCSI-2 Common access method
* transport and SCSI interface module
*
* ANNEX A :
*
* setsize() converts a read capacity value to int 13h
* head-cylinder-sector requirements. It minimizes the value for
* number of heads and maximizes the number of cylinders. This
* will support rather large disks before the number of heads
* will not fit in 4 bits (or 6 bits). This algorithm also
* minimizes the number of sectors that will be unused at the end
* of the disk while allowing for very large disks to be
* accommodated. This algorithm does not use physical geometry.
*/
static int setsize(unsigned long capacity, unsigned int *cyls, unsigned int *hds,
unsigned int *secs)
{
unsigned int rv = 0;
unsigned long heads, sectors, cylinders, temp;
cylinders = 1024L; /* Set number of cylinders to max */
sectors = 62L; /* Maximize sectors per track */
temp = cylinders * sectors; /* Compute divisor for heads */
heads = capacity / temp; /* Compute value for number of heads */
if (capacity % temp) { /* If no remainder, done! */
heads++; /* Else, increment number of heads */
temp = cylinders * heads; /* Compute divisor for sectors */
sectors = capacity / temp; /* Compute value for sectors per
track */
if (capacity % temp) { /* If no remainder, done! */
sectors++; /* Else, increment number of sectors */
temp = heads * sectors; /* Compute divisor for cylinders */
cylinders = capacity / temp; /* Compute number of cylinders */
}
}
if (cylinders == 0)
rv = (unsigned) -1; /* Give error if 0 cylinders */
*cyls = (unsigned int) cylinders; /* Stuff return values */
*secs = (unsigned int) sectors;
*hds = (unsigned int) heads;
return (rv);
}