scsi: scsi_debug: Change shost list lock to a mutex

The shost list lock, sdebug_host_list_lock, is a spinlock. We would only
lock in non-atomic context in this driver, so use a mutex instead, which is
friendlier if we need to schedule when iterating.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20230327074310.1862889-4-john.g.garry@oracle.com
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index eba6eca..a61e7c3 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -816,7 +816,7 @@ static int sdebug_cylinders_per;    /* cylinders per surface */
 static int sdebug_sectors_per;         /* sectors per cylinder */
 
 static LIST_HEAD(sdebug_host_list);
-static DEFINE_SPINLOCK(sdebug_host_list_lock);
+static DEFINE_MUTEX(sdebug_host_list_mutex);
 
 static struct xarray per_store_arr;
 static struct xarray *per_store_ap = &per_store_arr;
@@ -908,7 +908,7 @@ static void sdebug_max_tgts_luns(void)
        struct sdebug_host_info *sdbg_host;
        struct Scsi_Host *hpnt;
 
-       spin_lock(&sdebug_host_list_lock);
+       mutex_lock(&sdebug_host_list_mutex);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                hpnt = sdbg_host->shost;
                if ((hpnt->this_id >= 0) &&
@@ -919,7 +919,7 @@ static void sdebug_max_tgts_luns(void)
                /* sdebug_max_luns; */
                hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS + 1;
        }
-       spin_unlock(&sdebug_host_list_lock);
+       mutex_unlock(&sdebug_host_list_mutex);
 }
 
 enum sdeb_cmd_data {SDEB_IN_DATA = 0, SDEB_IN_CDB = 1};
@@ -1051,14 +1051,14 @@ static void all_config_cdb_len(void)
        struct Scsi_Host *shost;
        struct scsi_device *sdev;
 
-       spin_lock(&sdebug_host_list_lock);
+       mutex_lock(&sdebug_host_list_mutex);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                shost = sdbg_host->shost;
                shost_for_each_device(sdev, shost) {
                        config_cdb_len(sdev);
                }
        }
-       spin_unlock(&sdebug_host_list_lock);
+       mutex_unlock(&sdebug_host_list_mutex);
 }
 
 static void clear_luns_changed_on_target(struct sdebug_dev_info *devip)
@@ -5423,7 +5423,7 @@ static int scsi_debug_host_reset(struct scsi_cmnd *SCpnt)
        ++num_host_resets;
        if (SDEBUG_OPT_ALL_NOISE & sdebug_opts)
                sdev_printk(KERN_INFO, SCpnt->device, "%s\n", __func__);
-       spin_lock(&sdebug_host_list_lock);
+       mutex_lock(&sdebug_host_list_mutex);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                list_for_each_entry(devip, &sdbg_host->dev_info_list,
                                    dev_list) {
@@ -5431,7 +5431,7 @@ static int scsi_debug_host_reset(struct scsi_cmnd *SCpnt)
                        ++k;
                }
        }
-       spin_unlock(&sdebug_host_list_lock);
+       mutex_unlock(&sdebug_host_list_mutex);
        stop_all_queued();
        if (SDEBUG_OPT_RESET_NOISE & sdebug_opts)
                sdev_printk(KERN_INFO, SCpnt->device,
@@ -6337,13 +6337,13 @@ static ssize_t lun_format_store(struct device_driver *ddp, const char *buf,
                        struct sdebug_host_info *sdhp;
                        struct sdebug_dev_info *dp;
 
-                       spin_lock(&sdebug_host_list_lock);
+                       mutex_lock(&sdebug_host_list_mutex);
                        list_for_each_entry(sdhp, &sdebug_host_list, host_list) {
                                list_for_each_entry(dp, &sdhp->dev_info_list, dev_list) {
                                        set_bit(SDEBUG_UA_LUNS_CHANGED, dp->uas_bm);
                                }
                        }
-                       spin_unlock(&sdebug_host_list_lock);
+                       mutex_unlock(&sdebug_host_list_mutex);
                }
                return count;
        }
@@ -6373,7 +6373,7 @@ static ssize_t max_luns_store(struct device_driver *ddp, const char *buf,
                        struct sdebug_host_info *sdhp;
                        struct sdebug_dev_info *dp;
 
-                       spin_lock(&sdebug_host_list_lock);
+                       mutex_lock(&sdebug_host_list_mutex);
                        list_for_each_entry(sdhp, &sdebug_host_list,
                                            host_list) {
                                list_for_each_entry(dp, &sdhp->dev_info_list,
@@ -6382,7 +6382,7 @@ static ssize_t max_luns_store(struct device_driver *ddp, const char *buf,
                                                dp->uas_bm);
                                }
                        }
-                       spin_unlock(&sdebug_host_list_lock);
+                       mutex_unlock(&sdebug_host_list_mutex);
                }
                return count;
        }
@@ -6489,7 +6489,7 @@ static ssize_t virtual_gb_store(struct device_driver *ddp, const char *buf,
                        struct sdebug_host_info *sdhp;
                        struct sdebug_dev_info *dp;
 
-                       spin_lock(&sdebug_host_list_lock);
+                       mutex_lock(&sdebug_host_list_mutex);
                        list_for_each_entry(sdhp, &sdebug_host_list,
                                            host_list) {
                                list_for_each_entry(dp, &sdhp->dev_info_list,
@@ -6498,7 +6498,7 @@ static ssize_t virtual_gb_store(struct device_driver *ddp, const char *buf,
                                                dp->uas_bm);
                                }
                        }
-                       spin_unlock(&sdebug_host_list_lock);
+                       mutex_unlock(&sdebug_host_list_mutex);
                }
                return count;
        }
@@ -7258,9 +7258,9 @@ static int sdebug_add_host_helper(int per_host_idx)
                        goto clean;
        }
 
-       spin_lock(&sdebug_host_list_lock);
+       mutex_lock(&sdebug_host_list_mutex);
        list_add_tail(&sdbg_host->host_list, &sdebug_host_list);
-       spin_unlock(&sdebug_host_list_lock);
+       mutex_unlock(&sdebug_host_list_mutex);
 
        sdbg_host->dev.bus = &pseudo_lld_bus;
        sdbg_host->dev.parent = pseudo_primary;
@@ -7269,9 +7269,9 @@ static int sdebug_add_host_helper(int per_host_idx)
 
        error = device_register(&sdbg_host->dev);
        if (error) {
-               spin_lock(&sdebug_host_list_lock);
+               mutex_lock(&sdebug_host_list_mutex);
                list_del(&sdbg_host->host_list);
-               spin_unlock(&sdebug_host_list_lock);
+               mutex_unlock(&sdebug_host_list_mutex);
                goto clean;
        }
 
@@ -7311,7 +7311,7 @@ static void sdebug_do_remove_host(bool the_end)
        struct sdebug_host_info *sdbg_host = NULL;
        struct sdebug_host_info *sdbg_host2;
 
-       spin_lock(&sdebug_host_list_lock);
+       mutex_lock(&sdebug_host_list_mutex);
        if (!list_empty(&sdebug_host_list)) {
                sdbg_host = list_entry(sdebug_host_list.prev,
                                       struct sdebug_host_info, host_list);
@@ -7336,7 +7336,7 @@ static void sdebug_do_remove_host(bool the_end)
        }
        if (sdbg_host)
                list_del(&sdbg_host->host_list);
-       spin_unlock(&sdebug_host_list_lock);
+       mutex_unlock(&sdebug_host_list_mutex);
 
        if (!sdbg_host)
                return;