6.6-stable review patch. If anyone has any objections, please let me know.
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From: Bart Van Assche bvanassche@acm.org
[ 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@rowland.harvard.edu Cc: Douglas Gilbert dgilbert@interlog.com Fixes: bc4f24014de5 ("[SCSI] implement runtime Power Management") Signed-off-by: Bart Van Assche bvanassche@acm.org Link: https://lore.kernel.org/r/20241030220310.1373569-1-bvanassche@acm.org Acked-by: Alan Stern stern@rowland.harvard.edu Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/sg.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
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--;