--- /dev/null
+/******************************************************************************
+ * arch/xen/drivers/blkif/backend/interface.c
+ *
+ * Block-device interface management.
+ *
+ * Copyright (c) 2004, Keir Fraser
+ */
+
+#include "common.h"
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+#define VMALLOC_VMADDR(x) ((unsigned long)(x))
+#endif
+
+#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;
+}
+
+static void __blkif_disconnect_complete(void *arg)
+{
+ blkif_t *blkif = (blkif_t *)arg;
+ 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.sring);
+
+ /* 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_disconnect_complete(blkif_t *blkif)
+{
+ INIT_WORK(&blkif->work, __blkif_disconnect_complete, (void *)blkif);
+ schedule_work(&blkif->work);
+}
+
+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_sring_t *sring;
+
+ 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;
+ }
+ sring = (blkif_sring_t *)vma->addr;
+ SHARED_RING_INIT(sring);
+ BACK_RING_INIT(&blkif->blk_ring, sring, PAGE_SIZE);
+
+ blkif->evtchn = evtchn;
+ blkif->irq = bind_evtchn_to_irq(evtchn);
+ blkif->shmem_frame = shmem_frame;
+ 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, blkif);
+ blkif_deschedule(blkif);
+ blkif_put(blkif);
+ return 0; /* Caller should not send response message. */
+ }
+
+ disconnect->status = BLKIF_BE_STATUS_OKAY;
+ return 1;
+}
+
+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));
+}
git://git.onelab.eu / linux-2.6.git / blobdiff