This is a note to let you know that I've just added the patch titled
scsi: sg: Enable runtime power management
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-sg-enable-runtime-power-management.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 03162878cb7f6eb6161cc9afa9292fe03573dc47
Author: Bart Van Assche <bvanassche@xxxxxxx>
Date: Wed Oct 30 15:03:10 2024 -0700
scsi: sg: Enable runtime power management
[ Upstream commit 4045de893f691f75193c606aec440c365cf7a7be ]
In 2010, runtime power management support was implemented in the SCSI
core. The description of patch "[SCSI] implement runtime Power
Management" mentions that the sg driver is skipped but not why. This
patch enables runtime power management even if an instance of the sg
driver is held open. Enabling runtime PM for the sg driver is safe
because all interactions of the sg driver with the SCSI device pass
through the block layer (blk_execute_rq_nowait()) and the block layer
already supports runtime PM.
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Fixes: bc4f24014de5 ("[SCSI] implement runtime Power Management")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Link: https://lore.kernel.org/r/20241030220310.1373569-1-bvanassche@xxxxxxx
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index e6d8beb877766..dc9722b290f20 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -307,10 +307,6 @@ sg_open(struct inode *inode, struct file *filp)
if (retval)
goto sg_put;
- retval = scsi_autopm_get_device(device);
- if (retval)
- goto sdp_put;
-
/* scsi_block_when_processing_errors() may block so bypass
* check if O_NONBLOCK. Permits SCSI commands to be issued
* during error recovery. Tread carefully. */
@@ -318,7 +314,7 @@ sg_open(struct inode *inode, struct file *filp)
scsi_block_when_processing_errors(device))) {
retval = -ENXIO;
/* we are in error recovery for this device */
- goto error_out;
+ goto sdp_put;
}
mutex_lock(&sdp->open_rel_lock);
@@ -371,8 +367,6 @@ sg_open(struct inode *inode, struct file *filp)
}
error_mutex_locked:
mutex_unlock(&sdp->open_rel_lock);
-error_out:
- scsi_autopm_put_device(device);
sdp_put:
kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(device);
@@ -392,7 +386,6 @@ sg_release(struct inode *inode, struct file *filp)
SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
mutex_lock(&sdp->open_rel_lock);
- scsi_autopm_put_device(sdp->device);
kref_put(&sfp->f_ref, sg_remove_sfp);
sdp->open_cnt--;
