scsi: core: Remove the put_device() call from scsi_device_get()

scsi_device_get() may be called from atomic context, e.g. by
shost_for_each_device(). A later commit will allow put_device() to sleep
for SCSI devices. Hence remove the put_device() call from
scsi_device_get().

According to Rusty Russell's "Module Refcount and Stuff mini-FAQ", calling
module_put() from atomic context is allowed since considerable time. See
also https://lkml.org/lkml/2002/11/18/330.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221015002418.30955-8-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index c59eac7..9feb032 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -563,14 +563,14 @@ int scsi_device_get(struct scsi_device *sdev)
 {
        if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
                goto fail;
-       if (!get_device(&sdev->sdev_gendev))
-               goto fail;
        if (!try_module_get(sdev->host->hostt->module))
-               goto fail_put_device;
+               goto fail;
+       if (!get_device(&sdev->sdev_gendev))
+               goto fail_put_module;
        return 0;
 
-fail_put_device:
-       put_device(&sdev->sdev_gendev);
+fail_put_module:
+       module_put(sdev->host->hostt->module);
 fail:
        return -ENXIO;
 }