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From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
	Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
	Hannes Reinecke <hare@suse.de>,
	Mike Christie <michael.christie@oracle.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>
Subject: [PATCH v6 7/8] scsi: core: Remove the put_device() call from scsi_device_get()
Date: Thu, 29 Sep 2022 15:44:20 -0700	[thread overview]
Message-ID: <20220929224421.587465-8-bvanassche@acm.org> (raw)
In-Reply-To: <20220929224421.587465-1-bvanassche@acm.org>

scsi_device_get() may be called from atomic context, e.g. by
shost_for_each_device(). A later patch will allow put_device() to sleep
for SCSI devices. Hence this patch that removes 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>
---
 drivers/scsi/scsi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 086ec5b5862d..87bddd697fc6 100644
--- 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;
 }

  parent reply	other threads:[~2022-09-29 22:46 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-29 22:44 [PATCH v6 0/8] Prepare for constifying SCSI host templates Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 1/8] scsi: esas2r: Initialize two host template members implicitly Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 2/8] scsi: esas2r: Introduce scsi_template_proc_dir() Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 3/8] scsi: core: Fail host creation if creating the proc directory fails Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 4/8] scsi: core: Introduce a new list for SCSI proc directory entries Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 5/8] scsi: core: Rework scsi_single_lun_run() Bart Van Assche
2022-09-29 22:44 ` [PATCH v6 6/8] scsi: ufs: Simplify ufshcd_set_dev_pwr_mode() Bart Van Assche
2022-10-03  6:28   ` Adrian Hunter
2022-10-03 16:23     ` Bart Van Assche
2022-09-29 22:44 ` Bart Van Assche [this message]
2022-09-29 22:44 ` [PATCH v6 8/8] scsi: core: Release SCSI devices synchronously Bart Van Assche

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