forked from Minki/linux
ide-cd: remove the internal 64k buffer
This removes the internal ide-cd buffer and falls back to read-ahead block layer capabilities. Thorough testing (cd burning, dvd read, raw read) gives with the bufferless mode marginally better performance in addition to simplified code. bufferless: dd: reading `/dev/hdc': Input/output error 6238+0 records in 6238+0 records out 204406784 bytes (204 MB) copied, 259.891 s, 787 kB/s real 4m21.598s user 0m0.014s sys 0m0.744s with the old buffer (2.6.25-rc1): dd: reading `/dev/hdc': Input/output error 6238+0 records in 6238+0 records out 204406784 bytes (204 MB) copied, 262.893 s, 778 kB/s real 4m22.938s user 0m0.009s sys 0m0.771s Signed-off-by: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
This commit is contained in:
Borislav Petkov
Bartlomiej Zolnierkiewicz
parent
9841654949
commit
968c496413
@ -89,7 +89,6 @@ static void cdrom_saw_media_change (ide_drive_t *drive)
|
||||
|
||||
cd->cd_flags |= IDE_CD_FLAG_MEDIA_CHANGED;
|
||||
cd->cd_flags &= ~IDE_CD_FLAG_TOC_VALID;
|
||||
cd->nsectors_buffered = 0;
|
||||
}
|
||||
|
||||
static int cdrom_log_sense(ide_drive_t *drive, struct request *rq,
|
||||
@ -625,47 +624,6 @@ static void ide_cd_drain_data(ide_drive_t *drive, int nsects)
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Buffer up to SECTORS_TO_TRANSFER sectors from the drive in our sector
|
||||
* buffer. Once the first sector is added, any subsequent sectors are
|
||||
* assumed to be continuous (until the buffer is cleared). For the first
|
||||
* sector added, SECTOR is its sector number. (SECTOR is then ignored until
|
||||
* the buffer is cleared.)
|
||||
*/
|
||||
static void cdrom_buffer_sectors (ide_drive_t *drive, unsigned long sector,
|
||||
int sectors_to_transfer)
|
||||
{
|
||||
struct cdrom_info *info = drive->driver_data;
|
||||
|
||||
/* Number of sectors to read into the buffer. */
|
||||
int sectors_to_buffer = min_t(int, sectors_to_transfer,
|
||||
(SECTOR_BUFFER_SIZE >> SECTOR_BITS) -
|
||||
info->nsectors_buffered);
|
||||
|
||||
char *dest;
|
||||
|
||||
/* If we couldn't get a buffer, don't try to buffer anything... */
|
||||
if (info->buffer == NULL)
|
||||
sectors_to_buffer = 0;
|
||||
|
||||
/* If this is the first sector in the buffer, remember its number. */
|
||||
if (info->nsectors_buffered == 0)
|
||||
info->sector_buffered = sector;
|
||||
|
||||
/* Read the data into the buffer. */
|
||||
dest = info->buffer + info->nsectors_buffered * SECTOR_SIZE;
|
||||
while (sectors_to_buffer > 0) {
|
||||
HWIF(drive)->atapi_input_bytes(drive, dest, SECTOR_SIZE);
|
||||
--sectors_to_buffer;
|
||||
--sectors_to_transfer;
|
||||
++info->nsectors_buffered;
|
||||
dest += SECTOR_SIZE;
|
||||
}
|
||||
|
||||
/* Throw away any remaining data. */
|
||||
ide_cd_drain_data(drive, sectors_to_transfer);
|
||||
}
|
||||
|
||||
/*
|
||||
* Check the contents of the interrupt reason register from the cdrom
|
||||
* and attempt to recover if there are problems. Returns 0 if everything's
|
||||
@ -734,65 +692,6 @@ static int ide_cd_check_transfer_size(ide_drive_t *drive, int len)
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Try to satisfy some of the current read request from our cached data.
|
||||
* Returns nonzero if the request has been completed, zero otherwise.
|
||||
*/
|
||||
static int cdrom_read_from_buffer (ide_drive_t *drive)
|
||||
{
|
||||
struct cdrom_info *info = drive->driver_data;
|
||||
struct request *rq = HWGROUP(drive)->rq;
|
||||
unsigned short sectors_per_frame;
|
||||
|
||||
sectors_per_frame = queue_hardsect_size(drive->queue) >> SECTOR_BITS;
|
||||
|
||||
/* Can't do anything if there's no buffer. */
|
||||
if (info->buffer == NULL) return 0;
|
||||
|
||||
/* Loop while this request needs data and the next block is present
|
||||
in our cache. */
|
||||
while (rq->nr_sectors > 0 &&
|
||||
rq->sector >= info->sector_buffered &&
|
||||
rq->sector < info->sector_buffered + info->nsectors_buffered) {
|
||||
if (rq->current_nr_sectors == 0)
|
||||
cdrom_end_request(drive, 1);
|
||||
|
||||
memcpy (rq->buffer,
|
||||
info->buffer +
|
||||
(rq->sector - info->sector_buffered) * SECTOR_SIZE,
|
||||
SECTOR_SIZE);
|
||||
rq->buffer += SECTOR_SIZE;
|
||||
--rq->current_nr_sectors;
|
||||
--rq->nr_sectors;
|
||||
++rq->sector;
|
||||
}
|
||||
|
||||
/* If we've satisfied the current request,
|
||||
terminate it successfully. */
|
||||
if (rq->nr_sectors == 0) {
|
||||
cdrom_end_request(drive, 1);
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* Move on to the next buffer if needed. */
|
||||
if (rq->current_nr_sectors == 0)
|
||||
cdrom_end_request(drive, 1);
|
||||
|
||||
/* If this condition does not hold, then the kluge i use to
|
||||
represent the number of sectors to skip at the start of a transfer
|
||||
will fail. I think that this will never happen, but let's be
|
||||
paranoid and check. */
|
||||
if (rq->current_nr_sectors < bio_cur_sectors(rq->bio) &&
|
||||
(rq->sector & (sectors_per_frame - 1))) {
|
||||
printk(KERN_ERR "%s: cdrom_read_from_buffer: buffer botch (%ld)\n",
|
||||
drive->name, (long)rq->sector);
|
||||
cdrom_end_request(drive, 0);
|
||||
return -1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static ide_startstop_t cdrom_newpc_intr(ide_drive_t *);
|
||||
|
||||
/*
|
||||
@ -1134,11 +1033,9 @@ static ide_startstop_t cdrom_newpc_intr(ide_drive_t *drive)
|
||||
if (!ptr) {
|
||||
if (blk_fs_request(rq) && !write)
|
||||
/*
|
||||
* If the buffers are full, cache the rest
|
||||
* of the data in our internal buffer.
|
||||
*/
|
||||
cdrom_buffer_sectors(drive, rq->sector,
|
||||
thislen >> 9);
|
||||
* If the buffers are full, pipe the rest into
|
||||
* oblivion. */
|
||||
ide_cd_drain_data(drive, thislen >> 9);
|
||||
else {
|
||||
printk(KERN_ERR "%s: confused, missing data\n",
|
||||
drive->name);
|
||||
@ -1243,10 +1140,6 @@ static ide_startstop_t cdrom_start_rw(ide_drive_t *drive, struct request *rq)
|
||||
* weirdness which might be present in the request packet.
|
||||
*/
|
||||
restore_request(rq);
|
||||
|
||||
/* Satisfy whatever we can of this request from our cache. */
|
||||
if (cdrom_read_from_buffer(drive))
|
||||
return ide_stopped;
|
||||
}
|
||||
|
||||
/*
|
||||
@ -1262,9 +1155,6 @@ static ide_startstop_t cdrom_start_rw(ide_drive_t *drive, struct request *rq)
|
||||
} else
|
||||
cd->dma = drive->using_dma;
|
||||
|
||||
/* Clear the local sector buffer. */
|
||||
cd->nsectors_buffered = 0;
|
||||
|
||||
if (write)
|
||||
cd->devinfo.media_written = 1;
|
||||
|
||||
@ -2030,7 +1920,6 @@ static void ide_cd_release(struct kref *kref)
|
||||
ide_drive_t *drive = info->drive;
|
||||
struct gendisk *g = info->disk;
|
||||
|
||||
kfree(info->buffer);
|
||||
kfree(info->toc);
|
||||
if (devinfo->handle == drive)
|
||||
unregister_cdrom(devinfo);
|
||||
@ -2090,11 +1979,7 @@ static int idecd_open(struct inode * inode, struct file * file)
|
||||
if (!(info = ide_cd_get(disk)))
|
||||
return -ENXIO;
|
||||
|
||||
if (!info->buffer)
|
||||
info->buffer = kmalloc(SECTOR_BUFFER_SIZE, GFP_KERNEL|__GFP_REPEAT);
|
||||
|
||||
if (info->buffer)
|
||||
rc = cdrom_open(&info->devinfo, inode, file);
|
||||
rc = cdrom_open(&info->devinfo, inode, file);
|
||||
|
||||
if (rc < 0)
|
||||
ide_cd_put(info);
|
||||
|
||||
@ -119,10 +119,6 @@ struct cdrom_info {
|
||||
|
||||
struct atapi_toc *toc;
|
||||
|
||||
unsigned long sector_buffered;
|
||||
unsigned long nsectors_buffered;
|
||||
unsigned char *buffer;
|
||||
|
||||
/* The result of the last successful request sense command
|
||||
on this device. */
|
||||
struct request_sense sense_data;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user