ed007ca416
This version of libbdev support asynchronous communication, recovery after driver restarts, and retrying of failed transfer operations.
121 lines
2.6 KiB
C
121 lines
2.6 KiB
C
/* libbdev - tracking and reopening of opened minor devices */
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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 struct {
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dev_t dev;
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int count;
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int access;
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} open_dev[NR_OPEN_DEVS] = { { NO_DEV, 0, 0 } };
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int bdev_minor_reopen(dev_t dev)
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{
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/* Reopen all minor devices on a major device. This function duplicates some
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* code from elsewhere, because in this case we must avoid performing recovery.
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* FIXME: if reopening fails with a non-IPC error, we should attempt to close
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* all minors that we did manage to reopen so far, or they might stay open
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* forever.
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*/
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endpoint_t endpt;
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message m;
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int i, j, r, major;
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major = major(dev);
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endpt = bdev_driver_get(dev);
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assert(endpt != NONE);
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for (i = 0; i < NR_OPEN_DEVS; i++) {
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if (major(open_dev[i].dev) != major)
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continue;
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/* Each minor device may have been opened multiple times. Send an open
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* request for each time that it was opened before. We could reopen it
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* just once, but then we'd have to keep a shadow open count as well.
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*/
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for (j = 0; j < open_dev[i].count; j++) {
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memset(&m, 0, sizeof(m));
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m.m_type = BDEV_OPEN;
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m.BDEV_MINOR = minor(open_dev[i].dev);
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m.BDEV_ACCESS = open_dev[i].access;
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m.BDEV_ID = NO_ID;
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if ((r = sendrec(endpt, &m)) != OK) {
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printf("bdev: IPC to driver (%d) failed (%d)\n",
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endpt, r);
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return r;
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}
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if (m.m_type != BDEV_REPLY) {
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printf("bdev: driver (%d) sent weird response (%d)\n",
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endpt, m.m_type);
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return EINVAL;
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}
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if (m.BDEV_ID != NO_ID) {
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printf("bdev: driver (%d) sent invalid ID (%ld)\n",
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endpt, m.BDEV_ID);
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return EINVAL;
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}
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if ((r = m.BDEV_STATUS) != OK) {
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printf("bdev: driver (%d) failed device reopen (%d)\n",
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endpt, r);
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return r;
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}
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}
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}
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return OK;
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}
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void bdev_minor_add(dev_t dev, int access)
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{
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/* Increase the reference count of the given minor device.
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*/
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int i, free = -1;
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for (i = 0; i < NR_OPEN_DEVS; i++) {
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if (open_dev[i].dev == dev) {
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open_dev[i].count++;
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open_dev[i].access |= access;
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return;
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}
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if (free < 0 && open_dev[i].dev == NO_DEV)
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free = i;
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}
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if (free < 0) {
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printf("bdev: too many open devices, increase NR_OPEN_DEVS\n");
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return;
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}
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open_dev[free].dev = dev;
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open_dev[free].count = 1;
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open_dev[free].access = access;
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}
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void bdev_minor_del(dev_t dev)
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{
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/* Decrease the reference count of the given minor device, if present.
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*/
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int i;
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for (i = 0; i < NR_OPEN_DEVS; i++) {
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if (open_dev[i].dev == dev) {
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if (!--open_dev[i].count)
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open_dev[i].dev = NO_DEV;
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break;
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}
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}
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}
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