Avoid that disk probing hangs as follows if a SCSI host is removed
after disk scanning started and before it completed:
Call Trace:
__schedule+0x2fa/0xbb0
schedule+0x36/0x90
schedule_timeout+0x22c/0x570
io_schedule_timeout+0x1e/0x50
wait_for_completion_io_timeout+0x11f/0x180
blk_execute_rq+0x86/0xc0
scsi_execute+0xdb/0x1f0
sd_revalidate_disk+0xed/0x1c70 [sd_mod]
sd_probe_async+0xc3/0x1d0 [sd_mod]
async_run_entry_fn+0x38/0x160
process_one_work+0x20a/0x660
worker_thread+0x3d/0x3b0
kthread+0x13a/0x150
ret_from_fork+0x27/0x40
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
drivers/scsi/sd.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0313486d85c8..d5e2b73c02ea 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3225,11 +3225,13 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
{
struct scsi_disk *sdkp = data;
struct scsi_device *sdp;
+ struct Scsi_Host *host;
struct gendisk *gd;
u32 index;
struct device *dev;
sdp = sdkp->device;
+ host = sdp->host;
gd = sdkp->disk;
index = sdkp->index;
dev = &sdp->sdev_gendev;
@@ -3253,6 +3255,13 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
sdkp->first_scan = 1;
sdkp->max_medium_access_timeouts = SD_MAX_MEDIUM_TIMEOUTS;
+ mutex_lock(&host->scan_mutex);
+ if (!scsi_host_scan_allowed(host)) {
+ sd_printk(KERN_NOTICE, sdkp, "%s: host being removed\n",
+ __func__);
+ goto unlock;
+ }
+
sd_revalidate_disk(gd);
gd->flags = GENHD_FL_EXT_DEVT;
@@ -3276,8 +3285,12 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
sdp->removable ? "removable " : "");
+unlock:
+ mutex_unlock(&host->scan_mutex);
+ scsi_host_put(host);
scsi_autopm_put_device(sdp);
put_device(&sdkp->dev);
+ return;
}
/**
@@ -3377,7 +3390,15 @@ static int sd_probe(struct device *dev)
get_device(dev);
dev_set_drvdata(dev, sdkp);
- get_device(&sdkp->dev); /* prevent release before async_schedule */
+ /* prevent release before async_schedule */
+ error = -ENODEV;
+ if (scsi_host_get(sdp->host) == NULL) {
+ sd_printk(KERN_NOTICE, sdkp, "%s: host being removed\n",
+ __func__);
+ put_device(&sdkp->dev);
+ goto out;
+ }
+ get_device(&sdkp->dev);
async_schedule_domain(sd_probe_async, sdkp, &scsi_sd_probe_domain);
return 0;
--
2.14.3
