| Message ID | 20201022060753.21173-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/mremap_pages: Fix static key devmap_managed_key updates | expand |
> jump label: negative count! > WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 > Modules linked in: > …. > > Cc: Christoph Hellwig <hch@infradead.org> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> > Cc: linux-nvdimm@lists.01.org > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Jason Gunthorpe <jgg@mellanox.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > — Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> -Sachin
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: > commit 6f42193fd86e ("memremap: don't use a separate devm action for > devmap_managed_enable_get") changed the static key updates such that we > now call devmap_managed_enable_put() without doing the equivalent > devmap_managed_enable_get(). > > devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and > MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap > types too. This results in the below warning when switching between > system-ram and devdax mode for devdax namespace. > > jump label: negative count! > WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 > Modules linked in: > .... > > NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 > LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 > Call Trace: > [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) > [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 > [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 > [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 > [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 > [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 > [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 > [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 > [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 > [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 > [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 > [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 > [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 > [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 > [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 > [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 > [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c > > Cc: Christoph Hellwig <hch@infradead.org> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> > Cc: linux-nvdimm@lists.01.org > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Jason Gunthorpe <jgg@mellanox.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > mm/memremap.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/mm/memremap.c b/mm/memremap.c > index 73a206d0f645..d4402ff3e467 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) > { > unsigned long pfn; > int i; > + bool need_devmap_managed = false; > + > + switch (pgmap->type) { > + case MEMORY_DEVICE_PRIVATE: > + case MEMORY_DEVICE_FS_DAX: > + need_devmap_managed = true; > + break; > + default: > + break; > + } Is it overkill to avoid duplicating this switch logic in page_is_devmap_managed() by creating another call which can be used here? > > dev_pagemap_kill(pgmap); > for (i = 0; i < pgmap->nr_range; i++) > @@ -169,7 +179,8 @@ void memunmap_pages(struct dev_pagemap *pgmap) > pageunmap_range(pgmap, i); > > WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); > - devmap_managed_enable_put(); > + if (need_devmap_managed) > + devmap_managed_enable_put(); > } > EXPORT_SYMBOL_GPL(memunmap_pages); > > @@ -307,7 +318,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > .pgprot = PAGE_KERNEL, > }; > const int nr_range = pgmap->nr_range; > - bool need_devmap_managed = true; > + bool need_devmap_managed = false; I'm CC'ing Ralph Campbell because I think some of his work has proposed this same change. Ira > int error, i; > > if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) > @@ -327,6 +338,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > WARN(1, "Missing owner\n"); > return ERR_PTR(-EINVAL); > } > + need_devmap_managed = true; > break; > case MEMORY_DEVICE_FS_DAX: > if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || > @@ -334,13 +346,12 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > WARN(1, "File system DAX not supported\n"); > return ERR_PTR(-EINVAL); > } > + need_devmap_managed = true; > break; > case MEMORY_DEVICE_GENERIC: > - need_devmap_managed = false; > break; > case MEMORY_DEVICE_PCI_P2PDMA: > params.pgprot = pgprot_noncached(params.pgprot); > - need_devmap_managed = false; > break; > default: > WARN(1, "Invalid pgmap type %d\n", pgmap->type); > -- > 2.26.2 >
On 10/22/20 8:41 AM, Ira Weiny wrote: > On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: >> commit 6f42193fd86e ("memremap: don't use a separate devm action for >> devmap_managed_enable_get") changed the static key updates such that we >> now call devmap_managed_enable_put() without doing the equivalent >> devmap_managed_enable_get(). >> >> devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and >> MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap >> types too. This results in the below warning when switching between >> system-ram and devdax mode for devdax namespace. >> >> jump label: negative count! >> WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 >> Modules linked in: >> .... >> >> NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 >> LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 >> Call Trace: >> [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) >> [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 >> [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 >> [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 >> [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 >> [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >> [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >> [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 >> [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 >> [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 >> [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 >> [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >> [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >> [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 >> [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 >> [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 >> [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 >> [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 >> [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 >> [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 >> [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c >> >> Cc: Christoph Hellwig <hch@infradead.org> >> Cc: Dan Williams <dan.j.williams@intel.com> >> Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> >> Cc: linux-nvdimm@lists.01.org >> Cc: Ira Weiny <ira.weiny@intel.com> >> Cc: Jason Gunthorpe <jgg@mellanox.com> >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >> --- >> mm/memremap.c | 19 +++++++++++++++---- >> 1 file changed, 15 insertions(+), 4 deletions(-) >> >> diff --git a/mm/memremap.c b/mm/memremap.c >> index 73a206d0f645..d4402ff3e467 100644 >> --- a/mm/memremap.c >> +++ b/mm/memremap.c >> @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) >> { >> unsigned long pfn; >> int i; >> + bool need_devmap_managed = false; >> + >> + switch (pgmap->type) { >> + case MEMORY_DEVICE_PRIVATE: >> + case MEMORY_DEVICE_FS_DAX: >> + need_devmap_managed = true; >> + break; >> + default: >> + break; >> + } > > Is it overkill to avoid duplicating this switch logic in > page_is_devmap_managed() by creating another call which can be used here? Perhaps. I can imagine a helper defined in include/linux/mm.h which page_is_devmap_managed() could also call but that would impact a lot of places that include mm.h. Since memremap.c already has to have intimate knowledge of the pgmap->type, I think limiting the change to just what is needed is better for now. So the patch looks OK to me. Looking at this some more, I would suggest changing devmap_managed_enable_get() and devmap_managed_enable_put() to do the special case checking instead of doing it in memremap_pages() and memunmap_pages(). Then devmap_managed_enable_get() doesn't need to return an error if CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the following. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> --- mm/memremap.c | 39 ++++++++++++++++----------------------- 1 file changed, 16 insertions(+), 23 deletions(-) diff --git a/mm/memremap.c b/mm/memremap.c index 73a206d0f645..16b2fb482da1 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -41,28 +41,24 @@ EXPORT_SYMBOL_GPL(memremap_compat_align); DEFINE_STATIC_KEY_FALSE(devmap_managed_key); EXPORT_SYMBOL(devmap_managed_key); -static void devmap_managed_enable_put(void) +static void devmap_managed_enable_put(struct dev_pagemap *pgmap) { - static_branch_dec(&devmap_managed_key); + if (pgmap->type == MEMORY_DEVICE_PRIVATE || + pgmap->type == MEMORY_DEVICE_FS_DAX) + static_branch_dec(&devmap_managed_key); } -static int devmap_managed_enable_get(struct dev_pagemap *pgmap) +static void devmap_managed_enable_get(struct dev_pagemap *pgmap) { - if (pgmap->type == MEMORY_DEVICE_PRIVATE && - (!pgmap->ops || !pgmap->ops->page_free)) { - WARN(1, "Missing page_free method\n"); - return -EINVAL; - } - - static_branch_inc(&devmap_managed_key); - return 0; + if (pgmap->type == MEMORY_DEVICE_PRIVATE || + pgmap->type == MEMORY_DEVICE_FS_DAX) + static_branch_inc(&devmap_managed_key); } #else -static int devmap_managed_enable_get(struct dev_pagemap *pgmap) +static void devmap_managed_enable_get(struct dev_pagemap *pgmap) { - return -EINVAL; } -static void devmap_managed_enable_put(void) +static void devmap_managed_enable_put(struct dev_pagemap *pgmap) { } #endif /* CONFIG_DEV_PAGEMAP_OPS */ @@ -169,7 +165,7 @@ void memunmap_pages(struct dev_pagemap *pgmap) pageunmap_range(pgmap, i); WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); + devmap_managed_enable_put(pgmap); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -307,7 +303,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -323,6 +318,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing migrate_to_ram method\n"); return ERR_PTR(-EINVAL); } + if (!pgmap->ops->page_free) { + WARN(1, "Missing page_free method\n"); + return ERR_PTR(-EINVAL); + } if (!pgmap->owner) { WARN(1, "Missing owner\n"); return ERR_PTR(-EINVAL); @@ -336,11 +335,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) } break; case MEMORY_DEVICE_GENERIC: - need_devmap_managed = false; break; case MEMORY_DEVICE_PCI_P2PDMA: params.pgprot = pgprot_noncached(params.pgprot); - need_devmap_managed = false; break; default: WARN(1, "Invalid pgmap type %d\n", pgmap->type); @@ -364,11 +361,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) } } - if (need_devmap_managed) { - error = devmap_managed_enable_get(pgmap); - if (error) - return ERR_PTR(error); - } + devmap_managed_enable_get(pgmap); /* * Clear the pgmap nr_range as it will be incremented for each
On Thu, Oct 22, 2020 at 11:19:43AM -0700, Ralph Campbell wrote: > > On 10/22/20 8:41 AM, Ira Weiny wrote: > > On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: > > > commit 6f42193fd86e ("memremap: don't use a separate devm action for > > > devmap_managed_enable_get") changed the static key updates such that we > > > now call devmap_managed_enable_put() without doing the equivalent > > > devmap_managed_enable_get(). > > > > > > devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and > > > MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap > > > types too. This results in the below warning when switching between > > > system-ram and devdax mode for devdax namespace. > > > > > > jump label: negative count! > > > WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 > > > Modules linked in: > > > .... > > > > > > NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 > > > LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 > > > Call Trace: > > > [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) > > > [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 > > > [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 > > > [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 > > > [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 > > > [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > > > [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > > > [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 > > > [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 > > > [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 > > > [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 > > > [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > > > [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > > > [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 > > > [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 > > > [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 > > > [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 > > > [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 > > > [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 > > > [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 > > > [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c > > > > > > Cc: Christoph Hellwig <hch@infradead.org> > > > Cc: Dan Williams <dan.j.williams@intel.com> > > > Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> > > > Cc: linux-nvdimm@lists.01.org > > > Cc: Ira Weiny <ira.weiny@intel.com> > > > Cc: Jason Gunthorpe <jgg@mellanox.com> > > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > > > --- > > > mm/memremap.c | 19 +++++++++++++++---- > > > 1 file changed, 15 insertions(+), 4 deletions(-) > > > > > > diff --git a/mm/memremap.c b/mm/memremap.c > > > index 73a206d0f645..d4402ff3e467 100644 > > > --- a/mm/memremap.c > > > +++ b/mm/memremap.c > > > @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) > > > { > > > unsigned long pfn; > > > int i; > > > + bool need_devmap_managed = false; > > > + > > > + switch (pgmap->type) { > > > + case MEMORY_DEVICE_PRIVATE: > > > + case MEMORY_DEVICE_FS_DAX: > > > + need_devmap_managed = true; > > > + break; > > > + default: > > > + break; > > > + } > > > > Is it overkill to avoid duplicating this switch logic in > > page_is_devmap_managed() by creating another call which can be used here? > > Perhaps. I can imagine a helper defined in include/linux/mm.h which > page_is_devmap_managed() could also call but that would impact a lot of > places that include mm.h. Since memremap.c already has to have intimate > knowledge of the pgmap->type, I think limiting the change to just what > is needed is better for now. So the patch looks OK to me. > > Looking at this some more, I would suggest changing devmap_managed_enable_get() > and devmap_managed_enable_put() to do the special case checking instead of > doing it in memremap_pages() and memunmap_pages(). > Then devmap_managed_enable_get() doesn't need to return an error if > CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the > following. This looks cleaner to me. Aneesh? FWIW: Reviewed-by: Ira Weiny <ira.weiny@intel.com> Ira > > Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> > --- > mm/memremap.c | 39 ++++++++++++++++----------------------- > 1 file changed, 16 insertions(+), 23 deletions(-) > > diff --git a/mm/memremap.c b/mm/memremap.c > index 73a206d0f645..16b2fb482da1 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -41,28 +41,24 @@ EXPORT_SYMBOL_GPL(memremap_compat_align); > DEFINE_STATIC_KEY_FALSE(devmap_managed_key); > EXPORT_SYMBOL(devmap_managed_key); > -static void devmap_managed_enable_put(void) > +static void devmap_managed_enable_put(struct dev_pagemap *pgmap) > { > - static_branch_dec(&devmap_managed_key); > + if (pgmap->type == MEMORY_DEVICE_PRIVATE || > + pgmap->type == MEMORY_DEVICE_FS_DAX) > + static_branch_dec(&devmap_managed_key); > } > -static int devmap_managed_enable_get(struct dev_pagemap *pgmap) > +static void devmap_managed_enable_get(struct dev_pagemap *pgmap) > { > - if (pgmap->type == MEMORY_DEVICE_PRIVATE && > - (!pgmap->ops || !pgmap->ops->page_free)) { > - WARN(1, "Missing page_free method\n"); > - return -EINVAL; > - } > - > - static_branch_inc(&devmap_managed_key); > - return 0; > + if (pgmap->type == MEMORY_DEVICE_PRIVATE || > + pgmap->type == MEMORY_DEVICE_FS_DAX) > + static_branch_inc(&devmap_managed_key); > } > #else > -static int devmap_managed_enable_get(struct dev_pagemap *pgmap) > +static void devmap_managed_enable_get(struct dev_pagemap *pgmap) > { > - return -EINVAL; > } > -static void devmap_managed_enable_put(void) > +static void devmap_managed_enable_put(struct dev_pagemap *pgmap) > { > } > #endif /* CONFIG_DEV_PAGEMAP_OPS */ > @@ -169,7 +165,7 @@ void memunmap_pages(struct dev_pagemap *pgmap) > pageunmap_range(pgmap, i); > WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); > - devmap_managed_enable_put(); > + devmap_managed_enable_put(pgmap); > } > EXPORT_SYMBOL_GPL(memunmap_pages); > @@ -307,7 +303,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > .pgprot = PAGE_KERNEL, > }; > const int nr_range = pgmap->nr_range; > - bool need_devmap_managed = true; > int error, i; > if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) > @@ -323,6 +318,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > WARN(1, "Missing migrate_to_ram method\n"); > return ERR_PTR(-EINVAL); > } > + if (!pgmap->ops->page_free) { > + WARN(1, "Missing page_free method\n"); > + return ERR_PTR(-EINVAL); > + } > if (!pgmap->owner) { > WARN(1, "Missing owner\n"); > return ERR_PTR(-EINVAL); > @@ -336,11 +335,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > } > break; > case MEMORY_DEVICE_GENERIC: > - need_devmap_managed = false; > break; > case MEMORY_DEVICE_PCI_P2PDMA: > params.pgprot = pgprot_noncached(params.pgprot); > - need_devmap_managed = false; > break; > default: > WARN(1, "Invalid pgmap type %d\n", pgmap->type); > @@ -364,11 +361,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > } > } > - if (need_devmap_managed) { > - error = devmap_managed_enable_get(pgmap); > - if (error) > - return ERR_PTR(error); > - } > + devmap_managed_enable_get(pgmap); > /* > * Clear the pgmap nr_range as it will be incremented for each > -- > 2.20.1 > > > > dev_pagemap_kill(pgmap); > > > for (i = 0; i < pgmap->nr_range; i++) > > > @@ -169,7 +179,8 @@ void memunmap_pages(struct dev_pagemap *pgmap) > > > pageunmap_range(pgmap, i); > > > WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); > > > - devmap_managed_enable_put(); > > > + if (need_devmap_managed) > > > + devmap_managed_enable_put(); > > > } > > > EXPORT_SYMBOL_GPL(memunmap_pages); > > > @@ -307,7 +318,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > > > .pgprot = PAGE_KERNEL, > > > }; > > > const int nr_range = pgmap->nr_range; > > > - bool need_devmap_managed = true; > > > + bool need_devmap_managed = false; > > > > I'm CC'ing Ralph Campbell because I think some of his work has proposed this > > same change. > > > > Ira > > This part of the patch isn't strictly needed, it just reverses the default value of > need_devmap_managed. > > > > int error, i; > > > if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) > > > @@ -327,6 +338,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > > > WARN(1, "Missing owner\n"); > > > return ERR_PTR(-EINVAL); > > > } > > > + need_devmap_managed = true; > > > break; > > > case MEMORY_DEVICE_FS_DAX: > > > if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || > > > @@ -334,13 +346,12 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > > > WARN(1, "File system DAX not supported\n"); > > > return ERR_PTR(-EINVAL); > > > } > > > + need_devmap_managed = true; > > > break; > > > case MEMORY_DEVICE_GENERIC: > > > - need_devmap_managed = false; > > > break; > > > case MEMORY_DEVICE_PCI_P2PDMA: > > > params.pgprot = pgprot_noncached(params.pgprot); > > > - need_devmap_managed = false; > > > break; > > > default: > > > WARN(1, "Invalid pgmap type %d\n", pgmap->type); > > > -- > > > 2.26.2 > > >
On 10/23/20 12:40 AM, Ira Weiny wrote: > On Thu, Oct 22, 2020 at 11:19:43AM -0700, Ralph Campbell wrote: >> >> On 10/22/20 8:41 AM, Ira Weiny wrote: >>> On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: >>>> commit 6f42193fd86e ("memremap: don't use a separate devm action for >>>> devmap_managed_enable_get") changed the static key updates such that we >>>> now call devmap_managed_enable_put() without doing the equivalent >>>> devmap_managed_enable_get(). >>>> >>>> devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and >>>> MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap >>>> types too. This results in the below warning when switching between >>>> system-ram and devdax mode for devdax namespace. >>>> >>>> jump label: negative count! >>>> WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 >>>> Modules linked in: >>>> .... >>>> >>>> NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 >>>> LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 >>>> Call Trace: >>>> [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) >>>> [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 >>>> [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 >>>> [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 >>>> [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 >>>> [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >>>> [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >>>> [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 >>>> [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 >>>> [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 >>>> [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 >>>> [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >>>> [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >>>> [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 >>>> [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 >>>> [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 >>>> [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 >>>> [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 >>>> [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 >>>> [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 >>>> [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c >>>> >>>> Cc: Christoph Hellwig <hch@infradead.org> >>>> Cc: Dan Williams <dan.j.williams@intel.com> >>>> Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> >>>> Cc: linux-nvdimm@lists.01.org >>>> Cc: Ira Weiny <ira.weiny@intel.com> >>>> Cc: Jason Gunthorpe <jgg@mellanox.com> >>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >>>> --- >>>> mm/memremap.c | 19 +++++++++++++++---- >>>> 1 file changed, 15 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/mm/memremap.c b/mm/memremap.c >>>> index 73a206d0f645..d4402ff3e467 100644 >>>> --- a/mm/memremap.c >>>> +++ b/mm/memremap.c >>>> @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) >>>> { >>>> unsigned long pfn; >>>> int i; >>>> + bool need_devmap_managed = false; >>>> + >>>> + switch (pgmap->type) { >>>> + case MEMORY_DEVICE_PRIVATE: >>>> + case MEMORY_DEVICE_FS_DAX: >>>> + need_devmap_managed = true; >>>> + break; >>>> + default: >>>> + break; >>>> + } >>> >>> Is it overkill to avoid duplicating this switch logic in >>> page_is_devmap_managed() by creating another call which can be used here? >> >> Perhaps. I can imagine a helper defined in include/linux/mm.h which >> page_is_devmap_managed() could also call but that would impact a lot of >> places that include mm.h. Since memremap.c already has to have intimate >> knowledge of the pgmap->type, I think limiting the change to just what >> is needed is better for now. So the patch looks OK to me. >> >> Looking at this some more, I would suggest changing devmap_managed_enable_get() >> and devmap_managed_enable_put() to do the special case checking instead of >> doing it in memremap_pages() and memunmap_pages(). >> Then devmap_managed_enable_get() doesn't need to return an error if >> CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the >> following. > > This looks cleaner to me. Aneesh? > > FWIW: > Reviewed-by: Ira Weiny <ira.weiny@intel.com> > > Yes. You can add Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> -aneesh
>> Is it overkill to avoid duplicating this switch logic in >> page_is_devmap_managed() by creating another call which can be used here? > > Perhaps. I can imagine a helper defined in include/linux/mm.h which > page_is_devmap_managed() could also call but that would impact a lot of > places that include mm.h. Since memremap.c already has to have intimate > knowledge of the pgmap->type, I think limiting the change to just what > is needed is better for now. So the patch looks OK to me. > > Looking at this some more, I would suggest changing devmap_managed_enable_get() > and devmap_managed_enable_put() to do the special case checking instead of > doing it in memremap_pages() and memunmap_pages(). > Then devmap_managed_enable_get() doesn't need to return an error if > CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the > following. > > Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> > — This patch fixes the warning for me. Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> -Sachin
On Thu, Oct 22, 2020 at 11:19:43AM -0700, Ralph Campbell wrote: > > On 10/22/20 8:41 AM, Ira Weiny wrote: > > On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: > > > commit 6f42193fd86e ("memremap: don't use a separate devm action for > > > devmap_managed_enable_get") changed the static key updates such that we > > > now call devmap_managed_enable_put() without doing the equivalent > > > devmap_managed_enable_get(). > > > > > > devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and > > > MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap > > > types too. This results in the below warning when switching between > > > system-ram and devdax mode for devdax namespace. > > > > > > jump label: negative count! > > > WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 > > > Modules linked in: > > > .... > > > > > > NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 > > > LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 > > > Call Trace: > > > [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) > > > [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 > > > [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 > > > [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 > > > [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 > > > [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > > > [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > > > [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 > > > [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 > > > [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 > > > [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 > > > [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 > > > [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 > > > [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 > > > [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 > > > [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 > > > [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 > > > [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 > > > [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 > > > [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 > > > [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c > > > > > > Cc: Christoph Hellwig <hch@infradead.org> > > > Cc: Dan Williams <dan.j.williams@intel.com> > > > Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> > > > Cc: linux-nvdimm@lists.01.org > > > Cc: Ira Weiny <ira.weiny@intel.com> > > > Cc: Jason Gunthorpe <jgg@mellanox.com> > > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > > > --- > > > mm/memremap.c | 19 +++++++++++++++---- > > > 1 file changed, 15 insertions(+), 4 deletions(-) > > > > > > diff --git a/mm/memremap.c b/mm/memremap.c > > > index 73a206d0f645..d4402ff3e467 100644 > > > --- a/mm/memremap.c > > > +++ b/mm/memremap.c > > > @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) > > > { > > > unsigned long pfn; > > > int i; > > > + bool need_devmap_managed = false; > > > + > > > + switch (pgmap->type) { > > > + case MEMORY_DEVICE_PRIVATE: > > > + case MEMORY_DEVICE_FS_DAX: > > > + need_devmap_managed = true; > > > + break; > > > + default: > > > + break; > > > + } > > > > Is it overkill to avoid duplicating this switch logic in > > page_is_devmap_managed() by creating another call which can be used here? > > Perhaps. I can imagine a helper defined in include/linux/mm.h which > page_is_devmap_managed() could also call but that would impact a lot of > places that include mm.h. Since memremap.c already has to have intimate > knowledge of the pgmap->type, I think limiting the change to just what > is needed is better for now. So the patch looks OK to me. > > Looking at this some more, I would suggest changing devmap_managed_enable_get() > and devmap_managed_enable_put() to do the special case checking instead of > doing it in memremap_pages() and memunmap_pages(). > Then devmap_managed_enable_get() doesn't need to return an error if > CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the > following. > > Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> This looks ok as well. Can you submit it as a proper standalone patch?
On 10/22/20 11:46 PM, Christoph Hellwig wrote: > On Thu, Oct 22, 2020 at 11:19:43AM -0700, Ralph Campbell wrote: >> >> On 10/22/20 8:41 AM, Ira Weiny wrote: >>> On Thu, Oct 22, 2020 at 11:37:53AM +0530, Aneesh Kumar K.V wrote: >>>> commit 6f42193fd86e ("memremap: don't use a separate devm action for >>>> devmap_managed_enable_get") changed the static key updates such that we >>>> now call devmap_managed_enable_put() without doing the equivalent >>>> devmap_managed_enable_get(). >>>> >>>> devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and >>>> MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap >>>> types too. This results in the below warning when switching between >>>> system-ram and devdax mode for devdax namespace. >>>> >>>> jump label: negative count! >>>> WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 >>>> Modules linked in: >>>> .... >>>> >>>> NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 >>>> LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 >>>> Call Trace: >>>> [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) >>>> [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 >>>> [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 >>>> [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 >>>> [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 >>>> [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >>>> [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >>>> [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 >>>> [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 >>>> [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 >>>> [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 >>>> [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 >>>> [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 >>>> [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 >>>> [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 >>>> [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 >>>> [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 >>>> [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 >>>> [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 >>>> [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 >>>> [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c >>>> >>>> Cc: Christoph Hellwig <hch@infradead.org> >>>> Cc: Dan Williams <dan.j.williams@intel.com> >>>> Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> >>>> Cc: linux-nvdimm@lists.01.org >>>> Cc: Ira Weiny <ira.weiny@intel.com> >>>> Cc: Jason Gunthorpe <jgg@mellanox.com> >>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >>>> --- >>>> mm/memremap.c | 19 +++++++++++++++---- >>>> 1 file changed, 15 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/mm/memremap.c b/mm/memremap.c >>>> index 73a206d0f645..d4402ff3e467 100644 >>>> --- a/mm/memremap.c >>>> +++ b/mm/memremap.c >>>> @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) >>>> { >>>> unsigned long pfn; >>>> int i; >>>> + bool need_devmap_managed = false; >>>> + >>>> + switch (pgmap->type) { >>>> + case MEMORY_DEVICE_PRIVATE: >>>> + case MEMORY_DEVICE_FS_DAX: >>>> + need_devmap_managed = true; >>>> + break; >>>> + default: >>>> + break; >>>> + } >>> >>> Is it overkill to avoid duplicating this switch logic in >>> page_is_devmap_managed() by creating another call which can be used here? >> >> Perhaps. I can imagine a helper defined in include/linux/mm.h which >> page_is_devmap_managed() could also call but that would impact a lot of >> places that include mm.h. Since memremap.c already has to have intimate >> knowledge of the pgmap->type, I think limiting the change to just what >> is needed is better for now. So the patch looks OK to me. >> >> Looking at this some more, I would suggest changing devmap_managed_enable_get() >> and devmap_managed_enable_put() to do the special case checking instead of >> doing it in memremap_pages() and memunmap_pages(). >> Then devmap_managed_enable_get() doesn't need to return an error if >> CONFIG_DEV_PAGEMAP_OPS isn't defined. I have only compile tested the >> following. >> >> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> > > This looks ok as well. Can you submit it as a proper standalone patch? > Yes. I was just about to ask whether I should do that and you beat me to it.
diff --git a/mm/memremap.c b/mm/memremap.c index 73a206d0f645..d4402ff3e467 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -158,6 +158,16 @@ void memunmap_pages(struct dev_pagemap *pgmap) { unsigned long pfn; int i; + bool need_devmap_managed = false; + + switch (pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_FS_DAX: + need_devmap_managed = true; + break; + default: + break; + } dev_pagemap_kill(pgmap); for (i = 0; i < pgmap->nr_range; i++) @@ -169,7 +179,8 @@ void memunmap_pages(struct dev_pagemap *pgmap) pageunmap_range(pgmap, i); WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); + if (need_devmap_managed) + devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -307,7 +318,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; + bool need_devmap_managed = false; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -327,6 +338,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing owner\n"); return ERR_PTR(-EINVAL); } + need_devmap_managed = true; break; case MEMORY_DEVICE_FS_DAX: if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || @@ -334,13 +346,12 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "File system DAX not supported\n"); return ERR_PTR(-EINVAL); } + need_devmap_managed = true; break; case MEMORY_DEVICE_GENERIC: - need_devmap_managed = false; break; case MEMORY_DEVICE_PCI_P2PDMA: params.pgprot = pgprot_noncached(params.pgprot); - need_devmap_managed = false; break; default: WARN(1, "Invalid pgmap type %d\n", pgmap->type);
commit 6f42193fd86e ("memremap: don't use a separate devm action for devmap_managed_enable_get") changed the static key updates such that we now call devmap_managed_enable_put() without doing the equivalent devmap_managed_enable_get(). devmap_managed_enable_get() is only called for MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_FS_DAX, But memunmap_pages() get called for other pgmap types too. This results in the below warning when switching between system-ram and devdax mode for devdax namespace. jump label: negative count! WARNING: CPU: 52 PID: 1335 at kernel/jump_label.c:235 static_key_slow_try_dec+0x88/0xa0 Modules linked in: .... NIP [c000000000433318] static_key_slow_try_dec+0x88/0xa0 LR [c000000000433314] static_key_slow_try_dec+0x84/0xa0 Call Trace: [c000000025c1f660] [c000000000433314] static_key_slow_try_dec+0x84/0xa0 (unreliable) [c000000025c1f6d0] [c000000000433664] __static_key_slow_dec_cpuslocked+0x34/0xd0 [c000000025c1f700] [c0000000004337a4] static_key_slow_dec+0x54/0xf0 [c000000025c1f770] [c00000000059c49c] memunmap_pages+0x36c/0x500 [c000000025c1f820] [c000000000d91d10] devm_action_release+0x30/0x50 [c000000025c1f840] [c000000000d92e34] release_nodes+0x2f4/0x3e0 [c000000025c1f8f0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 [c000000025c1f930] [c000000000d883a4] bus_remove_device+0x124/0x210 [c000000025c1f9b0] [c000000000d80ef4] device_del+0x1d4/0x530 [c000000025c1fa70] [c000000000e341e8] unregister_dev_dax+0x48/0xe0 [c000000025c1fae0] [c000000000d91d10] devm_action_release+0x30/0x50 [c000000025c1fb00] [c000000000d92e34] release_nodes+0x2f4/0x3e0 [c000000025c1fbb0] [c000000000d8b15c] device_release_driver_internal+0x17c/0x280 [c000000025c1fbf0] [c000000000d87000] unbind_store+0x130/0x170 [c000000025c1fc30] [c000000000d862a0] drv_attr_store+0x40/0x60 [c000000025c1fc50] [c0000000006d316c] sysfs_kf_write+0x6c/0xb0 [c000000025c1fc90] [c0000000006d2328] kernfs_fop_write+0x118/0x280 [c000000025c1fce0] [c0000000005a79f8] vfs_write+0xe8/0x2a0 [c000000025c1fd30] [c0000000005a7d94] ksys_write+0x84/0x140 [c000000025c1fd80] [c00000000003a430] system_call_exception+0x120/0x270 [c000000025c1fe20] [c00000000000c540] system_call_common+0xf0/0x27c Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Sachin Sant <sachinp@linux.vnet.ibm.com> Cc: linux-nvdimm@lists.01.org Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- mm/memremap.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)