jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
scsi: add persistent reservation manager using qemu-pr-helper
This adds a concrete subclass of pr-manager that talks to qemu-pr-helper.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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scsi/Makefile.objs
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scsi/Makefile.objs
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scsi/pr-manager-helper.c
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scsi/pr-manager-helper.c
···
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/*
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* Persistent reservation manager that talks to qemu-pr-helper
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*
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* Copyright (c) 2017 Red Hat, Inc.
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*
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* Author: Paolo Bonzini <pbonzini@redhat.com>
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*
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* This code is licensed under the LGPL v2.1 or later.
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*
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "scsi/constants.h"
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#include "scsi/pr-manager.h"
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#include "scsi/utils.h"
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#include "io/channel.h"
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#include "io/channel-socket.h"
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#include "pr-helper.h"
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#include <scsi/sg.h>
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#define PR_MAX_RECONNECT_ATTEMPTS 5
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#define TYPE_PR_MANAGER_HELPER "pr-manager-helper"
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#define PR_MANAGER_HELPER(obj) \
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OBJECT_CHECK(PRManagerHelper, (obj), \
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TYPE_PR_MANAGER_HELPER)
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typedef struct PRManagerHelper {
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/* <private> */
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PRManager parent;
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char *path;
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QemuMutex lock;
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QIOChannel *ioc;
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} PRManagerHelper;
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/* Called with lock held. */
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static int pr_manager_helper_read(PRManagerHelper *pr_mgr,
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void *buf, int sz, Error **errp)
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{
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ssize_t r = qio_channel_read_all(pr_mgr->ioc, buf, sz, errp);
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if (r < 0) {
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object_unref(OBJECT(pr_mgr->ioc));
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pr_mgr->ioc = NULL;
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return -EINVAL;
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}
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return 0;
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}
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/* Called with lock held. */
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static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
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int fd,
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const void *buf, int sz, Error **errp)
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{
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size_t nfds = (fd != -1);
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while (sz > 0) {
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struct iovec iov;
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ssize_t n_written;
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iov.iov_base = (void *)buf;
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iov.iov_len = sz;
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n_written = qio_channel_writev_full(QIO_CHANNEL(pr_mgr->ioc), &iov, 1,
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nfds ? &fd : NULL, nfds, errp);
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if (n_written <= 0) {
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assert(n_written != QIO_CHANNEL_ERR_BLOCK);
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object_unref(OBJECT(pr_mgr->ioc));
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return n_written < 0 ? -EINVAL : 0;
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}
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nfds = 0;
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buf += n_written;
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sz -= n_written;
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}
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return 0;
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}
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/* Called with lock held. */
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static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr,
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Error **errp)
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{
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char *path = g_strdup(pr_mgr->path);
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SocketAddress saddr = {
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.type = SOCKET_ADDRESS_TYPE_UNIX,
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.u.q_unix.path = path
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};
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QIOChannelSocket *sioc = qio_channel_socket_new();
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Error *local_err = NULL;
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uint32_t flags;
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int r;
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assert(!pr_mgr->ioc);
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qio_channel_set_name(QIO_CHANNEL(sioc), "pr-manager-helper");
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qio_channel_socket_connect_sync(sioc,
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&saddr,
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&local_err);
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g_free(path);
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if (local_err) {
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object_unref(OBJECT(sioc));
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error_propagate(errp, local_err);
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return -ENOTCONN;
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}
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qio_channel_set_delay(QIO_CHANNEL(sioc), false);
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pr_mgr->ioc = QIO_CHANNEL(sioc);
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/* A simple feature negotation protocol, even though there is
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* no optional feature right now.
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*/
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r = pr_manager_helper_read(pr_mgr, &flags, sizeof(flags), errp);
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if (r < 0) {
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goto out_close;
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}
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flags = 0;
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r = pr_manager_helper_write(pr_mgr, -1, &flags, sizeof(flags), errp);
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if (r < 0) {
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goto out_close;
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}
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return 0;
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out_close:
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object_unref(OBJECT(pr_mgr->ioc));
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pr_mgr->ioc = NULL;
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return r;
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}
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static int pr_manager_helper_run(PRManager *p,
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int fd, struct sg_io_hdr *io_hdr)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p);
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uint32_t len;
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PRHelperResponse resp;
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int ret;
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int expected_dir;
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int attempts;
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uint8_t cdb[PR_HELPER_CDB_SIZE] = { 0 };
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if (!io_hdr->cmd_len || io_hdr->cmd_len > PR_HELPER_CDB_SIZE) {
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return -EINVAL;
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}
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memcpy(cdb, io_hdr->cmdp, io_hdr->cmd_len);
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assert(cdb[0] == PERSISTENT_RESERVE_OUT || cdb[0] == PERSISTENT_RESERVE_IN);
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expected_dir =
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(cdb[0] == PERSISTENT_RESERVE_OUT ? SG_DXFER_TO_DEV : SG_DXFER_FROM_DEV);
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if (io_hdr->dxfer_direction != expected_dir) {
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return -EINVAL;
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}
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len = scsi_cdb_xfer(cdb);
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if (io_hdr->dxfer_len < len || len > PR_HELPER_DATA_SIZE) {
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return -EINVAL;
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}
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qemu_mutex_lock(&pr_mgr->lock);
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/* Try to reconnect while sending the CDB. */
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for (attempts = 0; attempts < PR_MAX_RECONNECT_ATTEMPTS; attempts++) {
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if (!pr_mgr->ioc) {
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ret = pr_manager_helper_initialize(pr_mgr, NULL);
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if (ret < 0) {
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qemu_mutex_unlock(&pr_mgr->lock);
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g_usleep(G_USEC_PER_SEC);
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qemu_mutex_lock(&pr_mgr->lock);
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continue;
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}
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}
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ret = pr_manager_helper_write(pr_mgr, fd, cdb, ARRAY_SIZE(cdb), NULL);
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if (ret >= 0) {
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break;
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}
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}
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if (ret < 0) {
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goto out;
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}
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/* After sending the CDB, any communications failure causes the
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* command to fail. The failure is transient, retrying the command
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* will invoke pr_manager_helper_initialize again.
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*/
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if (expected_dir == SG_DXFER_TO_DEV) {
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io_hdr->resid = io_hdr->dxfer_len - len;
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ret = pr_manager_helper_write(pr_mgr, -1, io_hdr->dxferp, len, NULL);
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if (ret < 0) {
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goto out;
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}
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}
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ret = pr_manager_helper_read(pr_mgr, &resp, sizeof(resp), NULL);
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if (ret < 0) {
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goto out;
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}
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resp.result = be32_to_cpu(resp.result);
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resp.sz = be32_to_cpu(resp.sz);
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if (io_hdr->dxfer_direction == SG_DXFER_FROM_DEV) {
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assert(resp.sz <= io_hdr->dxfer_len);
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ret = pr_manager_helper_read(pr_mgr, io_hdr->dxferp, resp.sz, NULL);
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if (ret < 0) {
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goto out;
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}
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io_hdr->resid = io_hdr->dxfer_len - resp.sz;
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} else {
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assert(resp.sz == 0);
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}
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io_hdr->status = resp.result;
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if (resp.result == CHECK_CONDITION) {
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io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
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io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, PR_HELPER_SENSE_SIZE);
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memcpy(io_hdr->sbp, resp.sense, io_hdr->sb_len_wr);
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}
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out:
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if (ret < 0) {
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int sense_len = scsi_build_sense(io_hdr->sbp,
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SENSE_CODE(LUN_COMM_FAILURE));
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io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
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io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, sense_len);
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io_hdr->status = CHECK_CONDITION;
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}
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qemu_mutex_unlock(&pr_mgr->lock);
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return ret;
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}
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static void pr_manager_helper_complete(UserCreatable *uc, Error **errp)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(uc);
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qemu_mutex_lock(&pr_mgr->lock);
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pr_manager_helper_initialize(pr_mgr, errp);
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qemu_mutex_unlock(&pr_mgr->lock);
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}
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static char *get_path(Object *obj, Error **errp)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);
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return g_strdup(pr_mgr->path);
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}
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static void set_path(Object *obj, const char *str, Error **errp)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);
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g_free(pr_mgr->path);
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pr_mgr->path = g_strdup(str);
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}
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static void pr_manager_helper_instance_finalize(Object *obj)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);
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object_unref(OBJECT(pr_mgr->ioc));
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qemu_mutex_destroy(&pr_mgr->lock);
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}
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static void pr_manager_helper_instance_init(Object *obj)
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{
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PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);
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qemu_mutex_init(&pr_mgr->lock);
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}
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static void pr_manager_helper_class_init(ObjectClass *klass,
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void *class_data G_GNUC_UNUSED)
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{
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PRManagerClass *prmgr_klass = PR_MANAGER_CLASS(klass);
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UserCreatableClass *uc_klass = USER_CREATABLE_CLASS(klass);
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object_class_property_add_str(klass, "path", get_path, set_path,
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&error_abort);
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uc_klass->complete = pr_manager_helper_complete;
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prmgr_klass->run = pr_manager_helper_run;
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}
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static const TypeInfo pr_manager_helper_info = {
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.parent = TYPE_PR_MANAGER,
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.name = TYPE_PR_MANAGER_HELPER,
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.instance_size = sizeof(PRManagerHelper),
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.instance_init = pr_manager_helper_instance_init,
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.instance_finalize = pr_manager_helper_instance_finalize,
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.class_init = pr_manager_helper_class_init,
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};
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static void pr_manager_helper_register_types(void)
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{
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type_register_static(&pr_manager_helper_info);
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}
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type_init(pr_manager_helper_register_types);