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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)(_h))&(BLKIF_HASHSZ-1))
static kmem_cache_t *blkif_cachep;
static blkif_t *blkif_hash[BLKIF_HASHSZ];
blkif_t *blkif_find_by_handle(domid_t domid, unsigned int handle)
{
blkif_t *blkif = blkif_hash[BLKIF_HASH(domid, handle)];
while ( (blkif != NULL) &&
((blkif->domid != domid) || (blkif->handle != handle)) )
blkif = blkif->hash_next;
return blkif;
}
void __blkif_disconnect_complete(blkif_t *blkif)
{
ctrl_msg_t cmsg;
blkif_be_disconnect_t disc;
/*
* These can't be done in __blkif_disconnect() because at that point there
* may be outstanding requests at the disc whose asynchronous responses
* must still be notified to the remote driver.
*/
unbind_evtchn_from_irq(blkif->evtchn);
vfree(blkif->blk_ring_base);
/* Construct the deferred response message. */
cmsg.type = CMSG_BLKIF_BE;
cmsg.subtype = CMSG_BLKIF_BE_DISCONNECT;
cmsg.id = blkif->disconnect_rspid;
cmsg.length = sizeof(blkif_be_disconnect_t);
disc.domid = blkif->domid;
disc.blkif_handle = blkif->handle;
disc.status = BLKIF_BE_STATUS_OKAY;
memcpy(cmsg.msg, &disc, sizeof(disc));
/*
* Make sure message is constructed /before/ status change, because
* after the status change the 'blkif' structure could be deallocated at
* any time. Also make sure we send the response /after/ status change,
* as otherwise a subsequent CONNECT request could spuriously fail if
* another CPU doesn't see the status change yet.
*/
mb();
if ( blkif->status != DISCONNECTING )
BUG();
blkif->status = DISCONNECTED;
mb();
/* Send the successful response. */
ctrl_if_send_response(&cmsg);
}
void blkif_create(blkif_be_create_t *create)
{
domid_t domid = create->domid;
unsigned int handle = create->blkif_handle;
blkif_t **pblkif, *blkif;
if ( (blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL)) == NULL )
{
DPRINTK("Could not create blkif: out of memory\n");
create->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
return;
}
memset(blkif, 0, sizeof(*blkif));
blkif->domid = domid;
blkif->handle = handle;
blkif->status = DISCONNECTED;
spin_lock_init(&blkif->vbd_lock);
spin_lock_init(&blkif->blk_ring_lock);
atomic_set(&blkif->refcnt, 0);
pblkif = &blkif_hash[BLKIF_HASH(domid, handle)];
while ( *pblkif != NULL )
{
if ( ((*pblkif)->domid == domid) && ((*pblkif)->handle == handle) )
{
DPRINTK("Could not create blkif: already exists\n");
create->status = BLKIF_BE_STATUS_INTERFACE_EXISTS;
kmem_cache_free(blkif_cachep, blkif);
return;
}
pblkif = &(*pblkif)->hash_next;
}
blkif->hash_next = *pblkif;
*pblkif = blkif;
DPRINTK("Successfully created blkif\n");
create->status = BLKIF_BE_STATUS_OKAY;
}
void blkif_destroy(blkif_be_destroy_t *destroy)
{
domid_t domid = destroy->domid;
unsigned int handle = destroy->blkif_handle;
blkif_t **pblkif, *blkif;
pblkif = &blkif_hash[BLKIF_HASH(domid, handle)];
while ( (blkif = *pblkif) != NULL )
{
if ( (blkif->domid == domid) && (blkif->handle == handle) )
{
if ( blkif->status != DISCONNECTED )
goto still_connected;
goto destroy;
}
pblkif = &blkif->hash_next;
}
destroy->status = BLKIF_BE_STATUS_INTERFACE_NOT_FOUND;
return;
still_connected:
destroy->status = BLKIF_BE_STATUS_INTERFACE_CONNECTED;
return;
destroy:
*pblkif = blkif->hash_next;
destroy_all_vbds(blkif);
kmem_cache_free(blkif_cachep, blkif);
destroy->status = BLKIF_BE_STATUS_OKAY;
}
void blkif_connect(blkif_be_connect_t *connect)
{
domid_t domid = connect->domid;
unsigned int handle = connect->blkif_handle;
unsigned int evtchn = connect->evtchn;
unsigned long shmem_frame = connect->shmem_frame;
struct vm_struct *vma;
pgprot_t prot;
int error;
blkif_t *blkif;
blkif = blkif_find_by_handle(domid, handle);
if ( unlikely(blkif == NULL) )
{
DPRINTK("blkif_connect attempted for non-existent blkif (%u,%u)\n",
connect->domid, connect->blkif_handle);
connect->status = BLKIF_BE_STATUS_INTERFACE_NOT_FOUND;
return;
}
if ( (vma = get_vm_area(PAGE_SIZE, VM_IOREMAP)) == NULL )
{
connect->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
return;
}
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 )
connect->status = BLKIF_BE_STATUS_OUT_OF_MEMORY;
else if ( error == -EFAULT )
connect->status = BLKIF_BE_STATUS_MAPPING_ERROR;
else
connect->status = BLKIF_BE_STATUS_ERROR;
vfree(vma->addr);
return;
}
if ( blkif->status != DISCONNECTED )
{
connect->status = BLKIF_BE_STATUS_INTERFACE_CONNECTED;
vfree(vma->addr);
return;
}
blkif->evtchn = evtchn;
blkif->irq = bind_evtchn_to_irq(evtchn);
blkif->shmem_frame = shmem_frame;
blkif->blk_ring_base = (blkif_ring_t *)vma->addr;
blkif->status = CONNECTED;
blkif_get(blkif);
request_irq(blkif->irq, blkif_be_int, 0, "blkif-backend", blkif);
connect->status = BLKIF_BE_STATUS_OKAY;
}
int blkif_disconnect(blkif_be_disconnect_t *disconnect, u8 rsp_id)
{
domid_t domid = disconnect->domid;
unsigned int handle = disconnect->blkif_handle;
blkif_t *blkif;
blkif = blkif_find_by_handle(domid, handle);
if ( unlikely(blkif == NULL) )
{
DPRINTK("blkif_disconnect attempted for non-existent blkif"
" (%u,%u)\n", disconnect->domid, disconnect->blkif_handle);
disconnect->status = BLKIF_BE_STATUS_INTERFACE_NOT_FOUND;
return 1; /* Caller will send response error message. */
}
if ( blkif->status == CONNECTED )
{
blkif->status = DISCONNECTING;
blkif->disconnect_rspid = rsp_id;
wmb(); /* Let other CPUs see the status change. */
free_irq(blkif->irq, NULL);
blkif_deschedule(blkif);
blkif_put(blkif);
}
return 0; /* Caller should not send response message. */
}
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));
}
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