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Add the concept of a "user pointer" (similar to the void __user * in

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the kernel), which encapsulates the information needed to refer to an
external buffer.  Under normal operation, this can just be a void *
equivalent, but under -DKEEP_IT_REAL it would be a segoff_t equivalent.

Use this concept to avoid the need for bounce buffers in int13.c,
which reduces memory usage and opens up the possibility of using
multi-sector reads.

Extend the block-device API and the SCSI block device implementation
to support multi-sector reads.

Update iscsi.c to use user buffers.

Move the obsolete portions of realmode.h to old_realmode.h.

MS-DOS now boots an order of magnitude faster over iSCSI (~10 seconds
from power-up to C:> prompt in bochs).
This commit is contained in:
Michael Brown
2006-05-19 15:06:51 +00:00
parent 0ab92faedb
commit d48d0fb1bb
11 changed files with 154 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
src/arch/i386/interface/pcbios/int13.c
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@@ -93,7 +93,7 @@ static unsigned long chs_to_lba ( struct int13_drive *drive,
lba = ( ( ( ( cylinder * drive->heads ) + head )
* drive->sectors_per_track ) + sector - 1 );
DBG ( "C/H/S address %x/%x/%x -> LBA %x\n",
DBG ( "C/H/S address %x/%x/%x -> LBA %lx\n",
cylinder, head, sector, lba );
return lba;
@@ -111,19 +111,15 @@ static unsigned long chs_to_lba ( struct int13_drive *drive,
static int int13_read ( struct int13_drive *drive, uint64_t lba,
struct segoff data, unsigned long count ) {
struct block_device *blockdev = drive->blockdev;
size_t blksize = blockdev->blksize;
uint8_t buffer[blksize];
userptr_t buffer = real_to_user ( data.segment, data.offset );
int rc;
DBG ( "Read %lx sectors from %llx to %04x:%04x\n", count,
( unsigned long long ) lba, data.segment, data.offset );
while ( count-- ) {
if ( ( rc = blockdev->read ( blockdev, lba, buffer ) ) != 0 )
return INT13_STATUS_READ_ERROR;
copy_to_real ( data.segment, data.offset, buffer, blksize );
data.offset += blksize;
lba++;
}
if ( ( rc = blockdev->read ( blockdev, lba, count, buffer ) ) != 0 )
return INT13_STATUS_READ_ERROR;
return 0;
}
@@ -139,19 +135,15 @@ static int int13_read ( struct int13_drive *drive, uint64_t lba,
static int int13_write ( struct int13_drive *drive, uint64_t lba,
struct segoff data, unsigned long count ) {
struct block_device *blockdev = drive->blockdev;
size_t blksize = blockdev->blksize;
uint8_t buffer[blksize];
userptr_t buffer = real_to_user ( data.segment, data.offset );
int rc;
DBG ( "Write %lx sectors from %04x:%04x to %llx\n", count,
data.segment, data.offset, ( unsigned long long ) lba );
while ( count-- ) {
copy_from_real ( buffer, data.segment, data.offset, blksize );
if ( ( rc = blockdev->write ( blockdev, lba, buffer ) ) != 0 )
return INT13_STATUS_WRITE_ERROR;
data.offset += blksize;
lba++;
}
if ( ( rc = blockdev->write ( blockdev, lba, count, buffer ) ) != 0 )
return INT13_STATUS_WRITE_ERROR;
return 0;
}
@@ -202,7 +194,7 @@ static int int13_read_sectors ( struct int13_drive *drive,
};
if ( drive->blockdev->blksize != INT13_BLKSIZE ) {
DBG ( "Invalid blocksize (%d) for non-extended read\n",
DBG ( "Invalid blocksize (%zd) for non-extended read\n",
drive->blockdev->blksize );
return INT13_STATUS_INVALID;
}
@@ -233,7 +225,7 @@ static int int13_write_sectors ( struct int13_drive *drive,
};
if ( drive->blockdev->blksize != INT13_BLKSIZE ) {
DBG ( "Invalid blocksize (%d) for non-extended write\n",
DBG ( "Invalid blocksize (%zd) for non-extended write\n",
drive->blockdev->blksize );
return INT13_STATUS_INVALID;
}