| Message ID | accc6abc878f0662093b81490a1a052f2ff6f06e.1648687552.git.alison.schofield@intel.com |
|---|---|
| State | Accepted |
| Commit | 6aa657f416b65f23d7a3c9d04f144b1c4aa2ebc1 |
| Headers | show |
| Series | Do not allow set-partition immediate mode | expand |
On Wed, Mar 30, 2022 at 6:25 PM <alison.schofield@intel.com> wrote: > > From: Alison Schofield <alison.schofield@intel.com> > > With SET_PARTITION_INFO on the exclusive_cmds list for the CXL_PMEM > driver, userspace cannot execute a set-partition command without > first unbinding the pmem driver from the device. > > When userspace requests a partition change to take effect on the > next reboot this unbind requirement is unnecessarily restrictive. > The driver does not need to enforce an unbind because partitions > will not change until the next reboot. Of course, userspace still > needs to be aware that changing the size of persistent capacity > on the next reboot will result in the loss of data stored. That > can happen regardless of whether it is presently bound at the time > of issuing the set-partition command. > > When userspace requests a partition change to take effect immediately, > restrictions are needed. The CXL_MEM driver currently blocks the usage > of immediate mode, making the presence of SET_PARTITION_INFO, in this > exclusive commands list, redundant. > > In the future, when the CXL_MEM driver adds support for immediate > changes to device partitions it will ensure that the partition change > will not affect any active decode. That means the work will not fall > right back here, onto the CXL_PMEM driver. > > Signed-off-by: Alison Schofield <alison.schofield@intel.com> Looks good. Reviewed-by: Dan Williams <dan.j.williams@intel.com>
On Wed, 30 Mar 2022 18:27:19 -0700 alison.schofield@intel.com wrote: > From: Alison Schofield <alison.schofield@intel.com> > > With SET_PARTITION_INFO on the exclusive_cmds list for the CXL_PMEM > driver, userspace cannot execute a set-partition command without > first unbinding the pmem driver from the device. > > When userspace requests a partition change to take effect on the > next reboot this unbind requirement is unnecessarily restrictive. > The driver does not need to enforce an unbind because partitions > will not change until the next reboot. Of course, userspace still > needs to be aware that changing the size of persistent capacity > on the next reboot will result in the loss of data stored. That > can happen regardless of whether it is presently bound at the time > of issuing the set-partition command. > > When userspace requests a partition change to take effect immediately, > restrictions are needed. The CXL_MEM driver currently blocks the usage > of immediate mode, making the presence of SET_PARTITION_INFO, in this > exclusive commands list, redundant. > > In the future, when the CXL_MEM driver adds support for immediate > changes to device partitions it will ensure that the partition change > will not affect any active decode. That means the work will not fall > right back here, onto the CXL_PMEM driver. > > Signed-off-by: Alison Schofield <alison.schofield@intel.com> I gave a an RB on v3... To make it easy for whoever picks this up. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > drivers/cxl/pmem.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c > index 564d125d25ef..35c6f3af18f2 100644 > --- a/drivers/cxl/pmem.c > +++ b/drivers/cxl/pmem.c > @@ -344,7 +344,6 @@ static __init int cxl_pmem_init(void) > { > int rc; > > - set_bit(CXL_MEM_COMMAND_ID_SET_PARTITION_INFO, exclusive_cmds); > set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds); > set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds); >
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c index 564d125d25ef..35c6f3af18f2 100644 --- a/drivers/cxl/pmem.c +++ b/drivers/cxl/pmem.c @@ -344,7 +344,6 @@ static __init int cxl_pmem_init(void) { int rc; - set_bit(CXL_MEM_COMMAND_ID_SET_PARTITION_INFO, exclusive_cmds); set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds); set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds);