diff options
Diffstat (limited to 'linux-2.4.26-xen-sparse/arch/xen/drivers/blkif/backend/interface.c')
| -rw-r--r-- | linux-2.4.26-xen-sparse/arch/xen/drivers/blkif/backend/interface.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/linux-2.4.26-xen-sparse/arch/xen/drivers/blkif/backend/interface.c b/linux-2.4.26-xen-sparse/arch/xen/drivers/blkif/backend/interface.c new file mode 100644 index 0000000000..780d793c6c --- /dev/null +++ b/linux-2.4.26-xen-sparse/arch/xen/drivers/blkif/backend/interface.c @@ -0,0 +1,233 @@ +/****************************************************************************** + * 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)); +} |