| Message ID | 54E1D36B.4000905@plexistor.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2015-02-16 at 13:24 +0200, Boaz Harrosh wrote: > With old Kernels there was a bug in x86 where any unknown > memory chip type would come up BUSY when calling > request_mem_region_exclusive(). > > So for pmem to work with old Kernels and real NvDIMM chips > we have a new Kconfig option CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET. > > People have been running with hacked up pmem that will ignore > the return code from request_mem_region_exclusive. So here it is > official > > Signed-off-by: Boaz Harrosh <boaz@plexistor.com> I'm confused - I thought that this behavior was fixed by patch 1/3? With that patch this memory reservation should not fail, correct? If so, why do we need this patch? > --- > drivers/block/Kconfig | 12 ++++++++++++ > drivers/block/pmem.c | 11 +++++++---- > 2 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig > index 3b3200f..10879b8 100644 > --- a/drivers/block/Kconfig > +++ b/drivers/block/Kconfig > @@ -430,6 +430,18 @@ config BLK_DEV_PMEM_USE_PAGES > to other devices in the system, then you must say "Yes" here. > If unsure leave as Yes. > > +config BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET > + bool "Ignore the return code from request_mem_region_exclusive" > + depends on BLK_DEV_PMEM > + help > + In Old Kernels type-12 Memory type which is used by NvDIMM > + chips Comes out busy when calling request_mem_region_exclusive, > + because of a bug. > + If this option is set to "yes". The pmem will ignore the > + failure, and continue as usual. If you have an old Kernel and > + a real NvDIMM chip you must say yes here. > + (Ignored if BLK_DEV_PMEM_USE_PAGES=y) > + > config CDROM_PKTCDVD > tristate "Packet writing on CD/DVD media" > depends on !UML > diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c > index 9eb7ffe..f84d033 100644 > --- a/drivers/block/pmem.c > +++ b/drivers/block/pmem.c > @@ -197,10 +197,12 @@ int pmem_mapmem(struct pmem_device *pmem) > > res_mem = request_mem_region_exclusive(pmem->phys_addr, pmem->size, > "pmem"); > - if (!res_mem) { > + if (unlikely(!res_mem)) { > pr_warn("pmem: request_mem_region_exclusive phys=0x%llx size=0x%zx failed\n", > - pmem->phys_addr, pmem->size); > - return -EINVAL; > + pmem->phys_addr, pmem->size); > +#ifndef CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET > + return -EBUSY; > +#endif > } > > pmem->virt_addr = ioremap_cache(pmem->phys_addr, pmem->size); > @@ -211,7 +213,8 @@ int pmem_mapmem(struct pmem_device *pmem) > return 0; > > out_release: > - release_mem_region(pmem->phys_addr, pmem->size); > + if (res_mem) > + release_mem_region(pmem->phys_addr, pmem->size); > return err; > } >
On 02/17/2015 10:52 PM, Ross Zwisler wrote: > On Mon, 2015-02-16 at 13:24 +0200, Boaz Harrosh wrote: >> With old Kernels there was a bug in x86 where any unknown >> memory chip type would come up BUSY when calling >> request_mem_region_exclusive(). >> >> So for pmem to work with old Kernels and real NvDIMM chips >> we have a new Kconfig option CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET. >> >> People have been running with hacked up pmem that will ignore >> the return code from request_mem_region_exclusive. So here it is >> official >> >> Signed-off-by: Boaz Harrosh <boaz@plexistor.com> > Hi Ross, good morning > I'm confused - I thought that this behavior was fixed by patch 1/3? > With that patch this memory reservation should not fail, correct? > Yes, I have tested it extensively and PATCH-1/3 fixes this problem for sure. > If so, why do we need this patch? > I put in this patch for people that do-not-want/cannot compile their own Kernel but have a need for pmem.c regardless. I will not include this patch in the final submitted Kernel. Given that patch-1 gets accepted before the merge of pmem. Lets say that patch-1 and patch-3 are either or. A tree that has 1/3 does not need 3/3, a tree that does not have 1/3 needs 3/3. <> Thanks Boaz
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 3b3200f..10879b8 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -430,6 +430,18 @@ config BLK_DEV_PMEM_USE_PAGES to other devices in the system, then you must say "Yes" here. If unsure leave as Yes. +config BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET + bool "Ignore the return code from request_mem_region_exclusive" + depends on BLK_DEV_PMEM + help + In Old Kernels type-12 Memory type which is used by NvDIMM + chips Comes out busy when calling request_mem_region_exclusive, + because of a bug. + If this option is set to "yes". The pmem will ignore the + failure, and continue as usual. If you have an old Kernel and + a real NvDIMM chip you must say yes here. + (Ignored if BLK_DEV_PMEM_USE_PAGES=y) + config CDROM_PKTCDVD tristate "Packet writing on CD/DVD media" depends on !UML diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c index 9eb7ffe..f84d033 100644 --- a/drivers/block/pmem.c +++ b/drivers/block/pmem.c @@ -197,10 +197,12 @@ int pmem_mapmem(struct pmem_device *pmem) res_mem = request_mem_region_exclusive(pmem->phys_addr, pmem->size, "pmem"); - if (!res_mem) { + if (unlikely(!res_mem)) { pr_warn("pmem: request_mem_region_exclusive phys=0x%llx size=0x%zx failed\n", - pmem->phys_addr, pmem->size); - return -EINVAL; + pmem->phys_addr, pmem->size); +#ifndef CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET + return -EBUSY; +#endif } pmem->virt_addr = ioremap_cache(pmem->phys_addr, pmem->size); @@ -211,7 +213,8 @@ int pmem_mapmem(struct pmem_device *pmem) return 0; out_release: - release_mem_region(pmem->phys_addr, pmem->size); + if (res_mem) + release_mem_region(pmem->phys_addr, pmem->size); return err; }
With old Kernels there was a bug in x86 where any unknown memory chip type would come up BUSY when calling request_mem_region_exclusive(). So for pmem to work with old Kernels and real NvDIMM chips we have a new Kconfig option CONFIG_BLK_DEV_PMEM_IGNORE_REQUEST_MEM_RET. People have been running with hacked up pmem that will ignore the return code from request_mem_region_exclusive. So here it is official Signed-off-by: Boaz Harrosh <boaz@plexistor.com> --- drivers/block/Kconfig | 12 ++++++++++++ drivers/block/pmem.c | 11 +++++++---- 2 files changed, 19 insertions(+), 4 deletions(-)