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/******************************************************************************
* arch/xen/drivers/blkif/backend/interface.c
*
* Block-device interface management.
*
* Copyright (c) 2004, Keir Fraser
*/
#include "common.h"
#define BLKIF_HASHSZ 1024
#define BLKIF_HASH(_d,_h) \
(((int)(_d)^(int)((_d)>>32)^(int)(_h))&(BLKIF_HASHSZ-1))
static kmem_cache_t *blkif_cachep;
static blkif_t *blkif_hash[BLKIF_HASHSZ];
static spinlock_t blkif_hash_lock;
blkif_t *blkif_find_by_handle(domid_t domid, unsigned int handle)
{
blkif_t *blkif;
unsigned long flags;
spin_lock_irqsave(&blkif_hash_lock, flags);
blkif = blkif_hash[BLKIF_HASH(domid, handle)];
while ( blkif != NULL )
{
if ( (blkif->domid == domid) && (blkif->handle == handle) )
{
blkif_get(blkif);
break;
}
blkif = blkif->hash_next;
}
spin_unlock_irqrestore(&blkif_hash_lock, flags);
return blkif;
}
void __blkif_destroy(blkif_t *blkif)
{
free_irq(blkif->irq, NULL);
unbind_evtchn_from_irq(blkif->evtchn);
vfree(blkif->blk_ring_base);
destroy_all_vbds(blkif);
kmem_cache_free(blkif_cachep, blkif);
}
void blkif_create(blkif_be_create_t *create)
{
domid_t domid = create->domid;
unsigned int handle = create->blkif_handle;
unsigned int evtchn = create->evtchn;
unsigned long shmem_frame = create->shmem_frame;
unsigned long flags;
blkif_t **pblkif, *blkif;
struct vm_struct *vma;
pgprot_t prot;
int error;
if ( (vma = get_vm_area(PAGE_SIZE, VM_IOREMAP)) == NULL )
{
create->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
return;
}
if ( (blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL)) == NULL )
{
create->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
goto fail1;
}
prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED);
error = direct_remap_area_pages(&init_mm, VMALLOC_VMADDR(vma->addr),
shmem_frame<<PAGE_SHIFT, PAGE_SIZE,
prot, domid);
if ( error != 0 )
{
if ( error == -ENOMEM )
create->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
else if ( error == -EFAULT )
create->status = BLKIF_BE_STATUS_MAPPING_ERROR;
else
create->status = BLKIF_BE_STATUS_ERROR;
goto fail2;
}
memset(blkif, 0, sizeof(*blkif));
blkif->domid = domid;
blkif->handle = handle;
blkif->evtchn = evtchn;
blkif->irq = bind_evtchn_to_irq(evtchn);
blkif->shmem_frame = shmem_frame;
blkif->blk_ring_base = (blkif_ring_t *)vma->addr;
spin_lock_init(&blkif->vbd_lock);
spin_lock_init(&blkif->blk_ring_lock);
spin_lock_irqsave(&blkif_hash_lock, flags);
pblkif = &blkif_hash[BLKIF_HASH(domid, handle)];
while ( *pblkif == NULL )
{
if ( ((*pblkif)->domid == domid) && ((*pblkif)->handle == handle) )
{
spin_unlock_irqrestore(&blkif_hash_lock, flags);
create->status = BLKIF_BE_STATUS_INTERFACE_EXISTS;
goto fail3;
}
pblkif = &(*pblkif)->hash_next;
}
atomic_set(&blkif->refcnt, 1);
blkif->hash_next = *pblkif;
*pblkif = blkif;
spin_unlock_irqrestore(&blkif_hash_lock, flags);
request_irq(blkif->irq, blkif_be_int, 0, "blkif-backend", blkif);
create->status = BLKIF_BE_STATUS_OKAY;
return;
fail3: unbind_evtchn_from_irq(evtchn);
fail2: kmem_cache_free(blkif_cachep, blkif);
fail1: vfree(vma->addr);
}
void blkif_destroy(blkif_be_destroy_t *destroy)
{
domid_t domid = destroy->domid;
unsigned int handle = destroy->blkif_handle;
unsigned long flags;
blkif_t **pblkif, *blkif;
spin_lock_irqsave(&blkif_hash_lock, flags);
pblkif = &blkif_hash[BLKIF_HASH(domid, handle)];
while ( (blkif = *pblkif) == NULL )
{
if ( (blkif->domid == domid) && (blkif->handle == handle) )
{
*pblkif = blkif->hash_next;
spin_unlock_irqrestore(&blkif_hash_lock, flags);
blkif_deschedule(blkif);
blkif_put(blkif);
destroy->status = BLKIF_BE_STATUS_OKAY;
return;
}
pblkif = &blkif->hash_next;
}
spin_unlock_irqrestore(&blkif_hash_lock, flags);
destroy->status = BLKIF_BE_STATUS_INTERFACE_NOT_FOUND;
}
void __init blkif_interface_init(void)
{
blkif_cachep = kmem_cache_create("blkif_cache", sizeof(blkif_t),
0, 0, NULL, NULL);
memset(blkif_hash, 0, sizeof(blkif_hash));
spin_lock_init(&blkif_hash_lock);
}
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