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/* libbdev - asynchronous call structure management */
#include <minix/drivers.h>
#include <minix/bdev.h>
#include <assert.h>
#include "const.h"
#include "type.h"
#include "proto.h"
static bdev_call_t *calls[NR_CALLS];
bdev_call_t *bdev_call_alloc(int count)
{
/* Allocate a call structure.
*/
bdev_call_t *call;
bdev_id_t id;
for (id = 0; id < NR_CALLS; id++)
if (calls[id] == NULL)
break;
if (id == NR_CALLS)
return NULL;
call = malloc(sizeof(bdev_call_t) +
sizeof(call->gvec[0]) * (count - 1) +
sizeof(call->vec[0]) * count);
if (call == NULL)
return NULL;
call->id = id;
call->vec = (iovec_t *) &call->gvec[count];
calls[id] = call;
return call;
}
void bdev_call_free(bdev_call_t *call)
{
/* Free a call structure.
*/
assert(calls[call->id] == call);
calls[call->id] = NULL;
free(call);
}
bdev_call_t *bdev_call_get(bdev_id_t id)
{
/* Retrieve a call structure by request number.
*/
if (id < 0 || id >= NR_CALLS)
return NULL;
return calls[id];
}
bdev_call_t *bdev_call_find(dev_t dev)
{
/* Find the first asynchronous request for the given device, if any.
*/
bdev_id_t id;
for (id = 0; id < NR_CALLS; id++)
if (calls[id] != NULL && calls[id]->dev == dev)
return calls[id];
return NULL;
}
bdev_call_t *bdev_call_iter_maj(dev_t dev, bdev_call_t *call,
bdev_call_t **next)
{
/* Iterate over all asynchronous requests for a major device. This function
* must be safe even if the returned call structure is freed.
*/
bdev_id_t id;
int major;
major = major(dev);
/* If this is the first invocation, find the first match. Otherwise, take the
* call we found to be next in the last invocation, which may be NULL.
*/
if (call == NULL) {
for (id = 0; id < NR_CALLS; id++)
if (calls[id] != NULL && major(calls[id]->dev) == major)
break;
if (id == NR_CALLS)
return NULL;
call = calls[id];
} else {
if ((call = *next) == NULL)
return NULL;
}
/* Look for the next match, if any. */
*next = NULL;
for (id = call->id + 1; id < NR_CALLS; id++) {
if (calls[id] != NULL && major(calls[id]->dev) == major) {
*next = calls[id];
break;
}
}
return call;
}
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