[PATCH v3 03/11] scsi: scsi_debug: Change shost list lock to a mutex

John Garry
2023-03-27T07:43:57Z

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>
---
drivers/scsi/scsi_debug.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index eba6eca81e84..a61e7c31dab5 100644
--- 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;
--
2.35.3