| Message ID | 20231120073522.34180-2-dlemoal@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fix runtime suspended device resume | expand |
On 11/19/23 23:35, Damien Le Moal wrote: > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index 10480eb582b2..1fb460dfca0c 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -167,19 +167,19 @@ struct scsi_device { > * power state for system suspend/resume (suspend to RAM and > * hibernation) operations. > */ > - bool manage_system_start_stop; > + unsigned manage_system_start_stop:1; > > /* > * If true, let the high-level device driver (sd) manage the device > * power state for runtime device suspand and resume operations. > */ > - bool manage_runtime_start_stop; > + unsigned manage_runtime_start_stop:1; > > /* > * If true, let the high-level device driver (sd) manage the device > * power state for system shutdown (power off) operations. > */ > - bool manage_shutdown; > + unsigned manage_shutdown:1; > > unsigned removable:1; > unsigned changed:1; /* Data invalid due to media change */ Is there any code that modifies the above flags from different threads simultaneously? I'm wondering whether this patch introduces one or more race conditions related to changing these flags. Thanks, Bart.
On 11/21/23 01:06, Bart Van Assche wrote: > On 11/19/23 23:35, Damien Le Moal wrote: >> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h >> index 10480eb582b2..1fb460dfca0c 100644 >> --- a/include/scsi/scsi_device.h >> +++ b/include/scsi/scsi_device.h >> @@ -167,19 +167,19 @@ struct scsi_device { >> * power state for system suspend/resume (suspend to RAM and >> * hibernation) operations. >> */ >> - bool manage_system_start_stop; >> + unsigned manage_system_start_stop:1; >> >> /* >> * If true, let the high-level device driver (sd) manage the device >> * power state for runtime device suspand and resume operations. >> */ >> - bool manage_runtime_start_stop; >> + unsigned manage_runtime_start_stop:1; >> >> /* >> * If true, let the high-level device driver (sd) manage the device >> * power state for system shutdown (power off) operations. >> */ >> - bool manage_shutdown; >> + unsigned manage_shutdown:1; >> >> unsigned removable:1; >> unsigned changed:1; /* Data invalid due to media change */ > > Is there any code that modifies the above flags from different > threads simultaneously? I'm wondering whether this patch introduces > one or more race conditions related to changing these flags. These are set once when the LLD probes and initialize the scsi device and never changed again by the LLD. The manage_xxx_start_stop flags can be changed through sysfs though, but doing so would be a mistake as things would stop working as expected... I do think that we should change these flags to be RO in sysfs. Note that only libata and the firewire/sbp2 driver use these flags. > > Thanks, > > Bart.
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index c10ff8985203..63317449f6ea 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1056,8 +1056,8 @@ int ata_scsi_dev_config(struct scsi_device *sdev, struct ata_device *dev) * and resume and shutdown only. For system level suspend/resume, * devices power state is handled directly by libata EH. */ - sdev->manage_runtime_start_stop = true; - sdev->manage_shutdown = true; + sdev->manage_runtime_start_stop = 1; + sdev->manage_shutdown = 1; } /* diff --git a/drivers/firewire/sbp2.c b/drivers/firewire/sbp2.c index 7edf2c95282f..e779d866022b 100644 --- a/drivers/firewire/sbp2.c +++ b/drivers/firewire/sbp2.c @@ -1519,9 +1519,9 @@ static int sbp2_scsi_slave_configure(struct scsi_device *sdev) sdev->use_10_for_rw = 1; if (sbp2_param_exclusive_login) { - sdev->manage_system_start_stop = true; - sdev->manage_runtime_start_stop = true; - sdev->manage_shutdown = true; + sdev->manage_system_start_stop = 1; + sdev->manage_runtime_start_stop = 1; + sdev->manage_shutdown = 1; } if (sdev->type == TYPE_ROM) diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 10480eb582b2..1fb460dfca0c 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -167,19 +167,19 @@ struct scsi_device { * power state for system suspend/resume (suspend to RAM and * hibernation) operations. */ - bool manage_system_start_stop; + unsigned manage_system_start_stop:1; /* * If true, let the high-level device driver (sd) manage the device * power state for runtime device suspand and resume operations. */ - bool manage_runtime_start_stop; + unsigned manage_runtime_start_stop:1; /* * If true, let the high-level device driver (sd) manage the device * power state for system shutdown (power off) operations. */ - bool manage_shutdown; + unsigned manage_shutdown:1; unsigned removable:1; unsigned changed:1; /* Data invalid due to media change */
Commit 3cc2ffe5c16d ("scsi: sd: Differentiate system and runtime start/stop management") changed the single bit manage_start_stop flag into 2 boolean fields of the SCSI device structure. Commit 24eca2dce0f8 ("scsi: sd: Introduce manage_shutdown device flag") introduced the manage_shutdown boolean field for the same structure. Together, these 2 commits increase the size of struct scsi_device by 8 bytes by using booleans instead of defining the manage_xxx fields as single bit flags, similarly to other flags of this structure. Avoid this unnecessary structure size increase and be consistent with the definition of other flags by reverting the definitions of the manage_xxx fields as single bit flags. Fixes: 3cc2ffe5c16d ("scsi: sd: Differentiate system and runtime start/stop management") Fixes: 24eca2dce0f8 ("scsi: sd: Introduce manage_shutdown device flag") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal <dlemoal@kernel.org> --- drivers/ata/libata-scsi.c | 4 ++-- drivers/firewire/sbp2.c | 6 +++--- include/scsi/scsi_device.h | 6 +++--- 3 files changed, 8 insertions(+), 8 deletions(-)