diff options
Diffstat (limited to 'xenolinux-2.4.23-sparse/arch/xeno/drivers/block/xl_block.c')
| -rw-r--r-- | xenolinux-2.4.23-sparse/arch/xeno/drivers/block/xl_block.c | 577 |
1 files changed, 577 insertions, 0 deletions
diff --git a/xenolinux-2.4.23-sparse/arch/xeno/drivers/block/xl_block.c b/xenolinux-2.4.23-sparse/arch/xeno/drivers/block/xl_block.c new file mode 100644 index 0000000000..de71199c02 --- /dev/null +++ b/xenolinux-2.4.23-sparse/arch/xeno/drivers/block/xl_block.c @@ -0,0 +1,577 @@ +/****************************************************************************** + * xl_block.c + * + * Xenolinux virtual block-device driver. + * + */ + +#include "xl_block.h" +#include <linux/blk.h> +#include <linux/cdrom.h> + +typedef unsigned char byte; /* from linux/ide.h */ + +#define XLBLK_RESPONSE_IRQ _EVENT_BLKDEV +#define DEBUG_IRQ _EVENT_DEBUG + +#define STATE_ACTIVE 0 +#define STATE_SUSPENDED 1 +#define STATE_CLOSED 2 +static unsigned int state = STATE_SUSPENDED; + +static blk_ring_t *blk_ring; +static unsigned int resp_cons; /* Response consumer for comms ring. */ +static unsigned int req_prod; /* Private request producer. */ + +#define XDI_MAX 64 +static xen_disk_info_t xlblk_disk_info; /* information about our disks/VBDs */ + +/* We plug the I/O ring if the driver is suspended or if the ring is full. */ +#define RING_PLUGGED ((BLK_RING_INC(req_prod) == resp_cons) || \ + (state != STATE_ACTIVE)) + +/* + * Request queues with outstanding work, but ring is currently full. + * We need no special lock here, as we always access this with the + * io_request_lock held. We only need a small maximum list. + */ +#define MAX_PENDING 8 +static request_queue_t *pending_queues[MAX_PENDING]; +static int nr_pending; + +static kdev_t sg_dev; +static int sg_operation = -1; +static unsigned long sg_next_sect; +#define DISABLE_SCATTERGATHER() (sg_operation = -1) + +static inline void signal_requests_to_xen(void) +{ + block_io_op_t op; + + DISABLE_SCATTERGATHER(); + blk_ring->req_prod = req_prod; + + op.cmd = BLOCK_IO_OP_SIGNAL; + HYPERVISOR_block_io_op(&op); + return; +} + +static inline xl_disk_t *xldev_to_xldisk(kdev_t xldev) +{ + struct gendisk *gd = get_gendisk(xldev); + return (xl_disk_t *)gd->real_devices + + (MINOR(xldev) >> gd->minor_shift); +} + + +int xenolinux_block_open(struct inode *inode, struct file *filep) +{ + short xldev = inode->i_rdev; + struct gendisk *gd = get_gendisk(xldev); + xl_disk_t *disk = xldev_to_xldisk(inode->i_rdev); + short minor = MINOR(xldev); + + if ( gd->part[minor].nr_sects == 0 ) + { + /* + * Device either doesn't exist, or has zero capacity; we use a few + * cheesy heuristics to return the relevant error code + */ + if ( (gd->sizes[minor >> gd->minor_shift] != 0) || + ((minor & (gd->max_p - 1)) != 0) ) + { + /* + * We have a real device, but no such partition, or we just have a + * partition number so guess this is the problem. + */ + return -ENXIO; /* no such device or address */ + } + else if ( gd->flags[minor >> gd->minor_shift] & GENHD_FL_REMOVABLE ) + { + /* This is a removable device => assume that media is missing. */ + return -ENOMEDIUM; /* media not present (this is a guess) */ + } + else + { + /* Just go for the general 'no such device' error. */ + return -ENODEV; /* no such device */ + } + } + + disk->usage++; + DPRINTK("xenolinux_block_open\n"); + return 0; +} + + +int xenolinux_block_release(struct inode *inode, struct file *filep) +{ + xl_disk_t *disk = xldev_to_xldisk(inode->i_rdev); + disk->usage--; + DPRINTK("xenolinux_block_release\n"); + return 0; +} + + +int xenolinux_block_ioctl(struct inode *inode, struct file *filep, + unsigned command, unsigned long argument) +{ + kdev_t dev = inode->i_rdev; + struct hd_geometry *geo = (struct hd_geometry *)argument; + struct gendisk *gd; + struct hd_struct *part; + + /* NB. No need to check permissions. That is done for us. */ + + DPRINTK_IOCTL("command: 0x%x, argument: 0x%lx, dev: 0x%04x\n", + command, (long) argument, dev); + + gd = get_gendisk(dev); + part = &gd->part[MINOR(dev)]; + + switch ( command ) + { + case BLKGETSIZE: + DPRINTK_IOCTL(" BLKGETSIZE: %x %lx\n", BLKGETSIZE, part->nr_sects); + return put_user(part->nr_sects, (unsigned long *) argument); + + case BLKRRPART: /* re-read partition table */ + DPRINTK_IOCTL(" BLKRRPART: %x\n", BLKRRPART); + return xenolinux_block_revalidate(dev); + + case BLKSSZGET: + return hardsect_size[MAJOR(dev)][MINOR(dev)]; + + case BLKBSZGET: /* get block size */ + DPRINTK_IOCTL(" BLKBSZGET: %x\n", BLKBSZGET); + break; + + case BLKBSZSET: /* set block size */ + DPRINTK_IOCTL(" BLKBSZSET: %x\n", BLKBSZSET); + break; + + case BLKRASET: /* set read-ahead */ + DPRINTK_IOCTL(" BLKRASET: %x\n", BLKRASET); + break; + + case BLKRAGET: /* get read-ahead */ + DPRINTK_IOCTL(" BLKRAFET: %x\n", BLKRAGET); + break; + + case HDIO_GETGEO: + /* note: these values are complete garbage */ + DPRINTK_IOCTL(" HDIO_GETGEO: %x\n", HDIO_GETGEO); + if (!argument) return -EINVAL; + if (put_user(0x00, (unsigned long *) &geo->start)) return -EFAULT; + if (put_user(0xff, (byte *)&geo->heads)) return -EFAULT; + if (put_user(0x3f, (byte *)&geo->sectors)) return -EFAULT; + if (put_user(0x106, (unsigned short *)&geo->cylinders)) return -EFAULT; + return 0; + + case HDIO_GETGEO_BIG: + /* note: these values are complete garbage */ + DPRINTK_IOCTL(" HDIO_GETGEO_BIG: %x\n", HDIO_GETGEO_BIG); + if (!argument) return -EINVAL; + if (put_user(0x00, (unsigned long *) &geo->start)) return -EFAULT; + if (put_user(0xff, (byte *)&geo->heads)) return -EFAULT; + if (put_user(0x3f, (byte *)&geo->sectors)) return -EFAULT; + if (put_user(0x106, (unsigned int *) &geo->cylinders)) return -EFAULT; + return 0; + + case CDROMMULTISESSION: + DPRINTK("FIXME: support multisession CDs later\n"); + memset((struct cdrom_multisession *)argument, 0, + sizeof(struct cdrom_multisession)); + return 0; + + default: + printk("ioctl %08x not supported by xl_block\n", command); + return -ENOSYS; + } + + return 0; +} + +/* check media change: should probably do something here in some cases :-) */ +int xenolinux_block_check(kdev_t dev) +{ + DPRINTK("xenolinux_block_check\n"); + return 0; +} + +int xenolinux_block_revalidate(kdev_t dev) +{ + struct gendisk *gd = get_gendisk(dev); + xl_disk_t *disk = xldev_to_xldisk(dev); + unsigned long flags, capacity = gd->part[MINOR(dev)].nr_sects; + int i, disk_nr = MINOR(dev) >> gd->minor_shift; + + DPRINTK("xenolinux_block_revalidate: %d\n", dev); + + /* + * We didn't construct this VBD by reading a partition table. This + * function can only do bad things to us. + */ + if ( capacity == 0 ) + return -EINVAL; + + spin_lock_irqsave(&io_request_lock, flags); + if ( disk->usage > 1 ) + { + spin_unlock_irqrestore(&io_request_lock, flags); + return -EBUSY; + } + spin_unlock_irqrestore(&io_request_lock, flags); + + for ( i = gd->nr_real - 1; i >= 0; i-- ) + { + invalidate_device(dev+i, 1); + gd->part[MINOR(dev+i)].start_sect = 0; + gd->part[MINOR(dev+i)].nr_sects = 0; + } + + /* XXX Should perhaps revalidate VBDs here */ + + grok_partitions(gd, disk_nr, gd->nr_real, capacity); + + return 0; +} + + +/* + * hypervisor_request + * + * request block io + * + * id: for guest use only. + * operation: XEN_BLOCK_{READ,WRITE,PROBE,VBD*} + * buffer: buffer to read/write into. this should be a + * virtual address in the guest os. + */ +static int hypervisor_request(unsigned long id, + int operation, + char * buffer, + unsigned long sector_number, + unsigned short nr_sectors, + kdev_t device) +{ + unsigned long buffer_ma = phys_to_machine(virt_to_phys(buffer)); + struct gendisk *gd; + blk_ring_req_entry_t *req; + struct buffer_head *bh; + + if ( nr_sectors >= (1<<9) ) BUG(); + if ( (buffer_ma & ((1<<9)-1)) != 0 ) BUG(); + + if ( state == STATE_CLOSED ) + return 1; + + switch ( operation ) + { + + case XEN_BLOCK_READ: + case XEN_BLOCK_WRITE: + gd = get_gendisk(device); + + /* Update the sector_number we'll pass down as appropriate; note + that we could sanity check that resulting sector will be in + this partition, but this will happen in xen anyhow */ + sector_number += gd->part[MINOR(device)].start_sect; + + if ( (sg_operation == operation) && + (sg_dev == device) && + (sg_next_sect == sector_number) ) + { + req = &blk_ring->ring[(req_prod-1)&(BLK_RING_SIZE-1)].req; + bh = (struct buffer_head *)id; + bh->b_reqnext = (struct buffer_head *)req->id; + req->id = id; + req->buffer_and_sects[req->nr_segments] = buffer_ma | nr_sectors; + if ( ++req->nr_segments < MAX_BLK_SEGS ) + sg_next_sect += nr_sectors; + else + DISABLE_SCATTERGATHER(); + return 0; + } + else if ( RING_PLUGGED ) + { + return 1; + } + else + { + sg_operation = operation; + sg_dev = device; + sg_next_sect = sector_number + nr_sectors; + } + break; + + default: + panic("unknown op %d\n", operation); + } + + /* Fill out a communications ring structure. */ + req = &blk_ring->ring[req_prod].req; + req->id = id; + req->operation = operation; + req->sector_number = sector_number; + req->device = device; + req->nr_segments = 1; + req->buffer_and_sects[0] = buffer_ma | nr_sectors; + req_prod = BLK_RING_INC(req_prod); + + return 0; +} + + +/* + * do_xlblk_request + * read a block; request is in a request queue + */ +void do_xlblk_request(request_queue_t *rq) +{ + struct request *req; + struct buffer_head *bh, *next_bh; + int rw, nsect, full, queued = 0; + + DPRINTK("xlblk.c::do_xlblk_request for '%s'\n", DEVICE_NAME); + + while ( !rq->plugged && !list_empty(&rq->queue_head)) + { + if ( (req = blkdev_entry_next_request(&rq->queue_head)) == NULL ) + goto out; + + DPRINTK("do_xlblk_request %p: cmd %i, sec %lx, (%li/%li) bh:%p\n", + req, req->cmd, req->sector, + req->current_nr_sectors, req->nr_sectors, req->bh); + + rw = req->cmd; + if ( rw == READA ) rw = READ; + if ((rw != READ) && (rw != WRITE)) + panic("XenoLinux Virtual Block Device: bad cmd: %d\n", rw); + + req->errors = 0; + + bh = req->bh; + while ( bh != NULL ) + { + next_bh = bh->b_reqnext; + bh->b_reqnext = NULL; + + full = hypervisor_request( + (unsigned long)bh, + (rw == READ) ? XEN_BLOCK_READ : XEN_BLOCK_WRITE, + bh->b_data, bh->b_rsector, bh->b_size>>9, bh->b_rdev); + + if(full) { + + bh->b_reqnext = next_bh; + pending_queues[nr_pending++] = rq; + if ( nr_pending >= MAX_PENDING ) BUG(); + goto out; + + } + + queued++; + + /* Dequeue the buffer head from the request. */ + nsect = bh->b_size >> 9; + bh = req->bh = next_bh; + + if ( bh != NULL ) + { + /* There's another buffer head to do. Update the request. */ + req->hard_sector += nsect; + req->hard_nr_sectors -= nsect; + req->sector = req->hard_sector; + req->nr_sectors = req->hard_nr_sectors; + req->current_nr_sectors = bh->b_size >> 9; + req->buffer = bh->b_data; + } + else + { + /* That was the last buffer head. Finalise the request. */ + if ( end_that_request_first(req, 1, "XenBlk") ) BUG(); + blkdev_dequeue_request(req); + end_that_request_last(req); + } + } + } + + out: + if ( queued != 0 ) signal_requests_to_xen(); +} + + +static void kick_pending_request_queues(void) +{ + /* We kick pending request queues if the ring is reasonably empty. */ + if ( (nr_pending != 0) && + (((req_prod - resp_cons) & (BLK_RING_SIZE - 1)) < + (BLK_RING_SIZE >> 1)) ) + { + /* Attempt to drain the queue, but bail if the ring becomes full. */ + while ( nr_pending != 0 ) + { + do_xlblk_request(pending_queues[--nr_pending]); + if ( RING_PLUGGED ) break; + } + } +} + + +static void xlblk_response_int(int irq, void *dev_id, struct pt_regs *ptregs) +{ + int i; + unsigned long flags; + struct buffer_head *bh, *next_bh; + + if ( state == STATE_CLOSED ) + return; + + spin_lock_irqsave(&io_request_lock, flags); + + for ( i = resp_cons; + i != blk_ring->resp_prod; + i = BLK_RING_INC(i) ) + { + blk_ring_resp_entry_t *bret = &blk_ring->ring[i].resp; + switch (bret->operation) + { + case XEN_BLOCK_READ: + case XEN_BLOCK_WRITE: + if ( bret->status ) + DPRINTK("Bad return from blkdev data request: %lx\n", + bret->status); + for ( bh = (struct buffer_head *)bret->id; + bh != NULL; + bh = next_bh ) + { + next_bh = bh->b_reqnext; + bh->b_reqnext = NULL; + bh->b_end_io(bh, !bret->status); + } + break; + + default: + BUG(); + } + } + + resp_cons = i; + + kick_pending_request_queues(); + + spin_unlock_irqrestore(&io_request_lock, flags); +} + + + +static void reset_xlblk_interface(void) +{ + block_io_op_t op; + + nr_pending = 0; + + op.cmd = BLOCK_IO_OP_RESET; + if ( HYPERVISOR_block_io_op(&op) != 0 ) + printk(KERN_ALERT "Possible blkdev trouble: couldn't reset ring\n"); + + op.cmd = BLOCK_IO_OP_RING_ADDRESS; + (void)HYPERVISOR_block_io_op(&op); + + set_fixmap(FIX_BLKRING_BASE, op.u.ring_mfn << PAGE_SHIFT); + blk_ring = (blk_ring_t *)fix_to_virt(FIX_BLKRING_BASE); + blk_ring->req_prod = blk_ring->resp_prod = resp_cons = req_prod = 0; + + wmb(); + state = STATE_ACTIVE; +} + + +int __init xlblk_init(void) +{ + int error; + block_io_op_t op; + + reset_xlblk_interface(); + + error = request_irq(XLBLK_RESPONSE_IRQ, xlblk_response_int, + SA_SAMPLE_RANDOM, "blkdev", NULL); + if ( error ) + { + printk(KERN_ALERT "Could not allocate receive interrupt\n"); + goto fail; + } + + /* Setup our [empty] disk information structure */ + xlblk_disk_info.max = XDI_MAX; + xlblk_disk_info.disks = kmalloc(XDI_MAX * sizeof(xen_disk_t), GFP_KERNEL); + xlblk_disk_info.count = 0; + + /* Probe for disk information. */ + memset(&op, 0, sizeof(op)); + op.cmd = BLOCK_IO_OP_VBD_PROBE; + op.u.probe_params.domain = 0; + memcpy(&op.u.probe_params.xdi, &xlblk_disk_info, sizeof(xlblk_disk_info)); + + error = HYPERVISOR_block_io_op(&op); + + if ( error ) + { + printk(KERN_ALERT "Could not probe disks (%d)\n", error); + free_irq(XLBLK_RESPONSE_IRQ, NULL); + goto fail; + } + + /* copy back the [updated] count parameter */ + xlblk_disk_info.count = op.u.probe_params.xdi.count; + + /* Pass the information to our virtual block device susbystem. */ + xlvbd_init(&xlblk_disk_info); + + return 0; + + fail: + return error; +} + +static void __exit xlblk_cleanup(void) +{ + xlvbd_cleanup(); + free_irq(XLBLK_RESPONSE_IRQ, NULL); +} + + +#ifdef MODULE +module_init(xlblk_init); +module_exit(xlblk_cleanup); +#endif + + +void blkdev_suspend(void) +{ + state = STATE_SUSPENDED; + wmb(); + + while ( resp_cons != blk_ring->req_prod ) + { + barrier(); + current->state = TASK_INTERRUPTIBLE; + schedule_timeout(1); + } + + wmb(); + state = STATE_CLOSED; + wmb(); + + clear_fixmap(FIX_BLKRING_BASE); +} + + +void blkdev_resume(void) +{ + reset_xlblk_interface(); + spin_lock_irq(&io_request_lock); + kick_pending_request_queues(); + spin_unlock_irq(&io_request_lock); +} |