Tha patch implements SCM async-flush hcall and sets the ND_REGION_ASYNC capability when the platform device tree has "ibm,async-flush-required" set.
The below demonstration shows the map_sync behavior when ibm,async-flush-required is present in device tree. (https://github.com/avocado-framework-tests/avocado-misc-tests/blob/master/memory/ndctl.py.data/map_sync.c) The pmem0 is from nvdimm without async-flush-required, and pmem1 is from nvdimm with async-flush-required, mounted as /dev/pmem0 on /mnt1 type xfs (rw,relatime,attr2,dax=always,inode64,logbufs=8,logbsize=32k,noquota) /dev/pmem1 on /mnt2 type xfs (rw,relatime,attr2,dax=always,inode64,logbufs=8,logbsize=32k,noquota) #./mapsync /mnt1/newfile ----> Without async-flush-required #./mapsync /mnt2/newfile ----> With async-flush-required Failed to mmap with Operation not supported Signed-off-by: Shivaprasad G Bhat <sb...@linux.ibm.com> --- The HCALL semantics are in review, not final. Documentation/powerpc/papr_hcalls.rst | 14 ++++++++++ arch/powerpc/include/asm/hvcall.h | 3 +- arch/powerpc/platforms/pseries/papr_scm.c | 39 +++++++++++++++++++++++++++++ 3 files changed, 55 insertions(+), 1 deletion(-) diff --git a/Documentation/powerpc/papr_hcalls.rst b/Documentation/powerpc/papr_hcalls.rst index 48fcf1255a33..cc310814f24c 100644 --- a/Documentation/powerpc/papr_hcalls.rst +++ b/Documentation/powerpc/papr_hcalls.rst @@ -275,6 +275,20 @@ Health Bitmap Flags: Given a DRC Index collect the performance statistics for NVDIMM and copy them to the resultBuffer. +**H_SCM_ASYNC_FLUSH** + +| Input: *drcIndex* +| Out: *continue-token* +| Return Value: *H_SUCCESS, H_Parameter, H_P2, H_BUSY* + +Given a DRC Index Flush the data to backend NVDIMM device. + +The hcall returns H_BUSY when the flush takes longer time and the hcall needs +to be issued multiple times in order to be completely serviced. The +*continue-token* from the output to be passed in the argument list in +subsequent hcalls to the hypervisor until the hcall is completely serviced +at which point H_SUCCESS is returned by the hypervisor. + References ========== .. [1] "Power Architecture Platform Reference" diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index c1fbccb04390..4a13074bc782 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -306,7 +306,8 @@ #define H_SCM_HEALTH 0x400 #define H_SCM_PERFORMANCE_STATS 0x418 #define H_RPT_INVALIDATE 0x448 -#define MAX_HCALL_OPCODE H_RPT_INVALIDATE +#define H_SCM_ASYNC_FLUSH 0x4A0 +#define MAX_HCALL_OPCODE H_SCM_ASYNC_FLUSH /* Scope args for H_SCM_UNBIND_ALL */ #define H_UNBIND_SCOPE_ALL (0x1) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 835163f54244..1f8c5153cb3d 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -93,6 +93,7 @@ struct papr_scm_priv { uint64_t block_size; int metadata_size; bool is_volatile; + bool async_flush_required; uint64_t bound_addr; @@ -117,6 +118,38 @@ struct papr_scm_priv { size_t stat_buffer_len; }; +static int papr_scm_pmem_flush(struct nd_region *nd_region, struct bio *bio) +{ + unsigned long ret[PLPAR_HCALL_BUFSIZE]; + struct papr_scm_priv *p = nd_region_provider_data(nd_region); + int64_t rc; + uint64_t token = 0; + + do { + rc = plpar_hcall(H_SCM_ASYNC_FLUSH, ret, p->drc_index, token); + + /* Check if we are stalled for some time */ + token = ret[0]; + if (H_IS_LONG_BUSY(rc)) { + msleep(get_longbusy_msecs(rc)); + rc = H_BUSY; + } else if (rc == H_BUSY) { + cond_resched(); + } + + } while (rc == H_BUSY); + + if (rc) + dev_err(&p->pdev->dev, "flush error: %lld\n", rc); + else + dev_dbg(&p->pdev->dev, "flush drc 0x%x complete\n", + p->drc_index); + + dev_dbg(&p->pdev->dev, "Flush call complete\n"); + + return rc; +} + static LIST_HEAD(papr_nd_regions); static DEFINE_MUTEX(papr_ndr_lock); @@ -943,6 +976,11 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p) ndr_desc.num_mappings = 1; ndr_desc.nd_set = &p->nd_set; + if (p->async_flush_required) { + set_bit(ND_REGION_ASYNC, &ndr_desc.flags); + ndr_desc.flush = papr_scm_pmem_flush; + } + if (p->is_volatile) p->region = nvdimm_volatile_region_create(p->bus, &ndr_desc); else { @@ -1088,6 +1126,7 @@ static int papr_scm_probe(struct platform_device *pdev) p->block_size = block_size; p->blocks = blocks; p->is_volatile = !of_property_read_bool(dn, "ibm,cache-flush-required"); + p->async_flush_required = of_property_read_bool(dn, "ibm,async-flush-required"); /* We just need to ensure that set cookies are unique across */ uuid_parse(uuid_str, (uuid_t *) uuid);
