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