On 10/21/22 15:21, Hannes Reinecke wrote: > On 10/21/22 07:38, Damien Le Moal wrote: >> From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx> >> >> Currently, the libata.fua parameter isn't runtime-writable, so a >> system restart is required in order to toggle it. >> This unnecessarily complicates testing how drives behave with FUA on and >> off. >> >> Let's make this parameter R/W instead, like many others in the kernel. >> >> Example usage: >> Disable the parameter: >> echo 0 >/sys/module/libata/parameters/fua >> >> Revalidate disk cache settings: >> F=/sys/class/scsi_disk/0\:0\:0\:0/cache_type; echo `cat $F` >$F >> >> [Damien] >> Enabling fua support by setting libata.fua to 1 will have no effect if >> the libata module is loaded with libata.force=[ID]nofua, which disables >> fua support for the ata device(s) identified with ID or all ata devices >> if no ID is specified. >> >> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx> >> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> >> --- >> drivers/ata/libata-core.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c >> index 6008f7ed1c42..1bb9616b10d9 100644 >> --- a/drivers/ata/libata-core.c >> +++ b/drivers/ata/libata-core.c >> @@ -128,7 +128,7 @@ module_param(atapi_passthru16, int, 0444); >> MODULE_PARM_DESC(atapi_passthru16, "Enable ATA_16 passthru for ATAPI devices (0=off, 1=on [default])"); >> >> int libata_fua = 0; >> -module_param_named(fua, libata_fua, int, 0444); >> +module_param_named(fua, libata_fua, int, 0644); >> MODULE_PARM_DESC(fua, "FUA support (0=off [default], 1=on)"); >> >> static int ata_ignore_hpa; > Hmm. I guess you'll need to revalidate the drive when changing that; but > this can be done in a later patch. Well, this is not sysfs, we cannot do this automatically easily... And thinking about it now that you mention it, going from fua=1 to fua=0 can actually cause problems. The reverse not, since scsi side would still see fua=0 until revalidation. So... Unless we find a way to link the param write to reavlidation, we should actually not allow this. Maciej ? Thoughts ? > > Reviewed-by: Hannes Reinecke <hare@xxxxxxx> > > Cheers, > > Hannes -- Damien Le Moal Western Digital Research
