device-dax/kmem: introduce dax_kmem_range()

Towards removing the mode specific @dax_kmem_res attribute from the
generic 'struct dev_dax', and preparing for multi-range support, teach the
driver to calculate the hotplug range from the device range.  The hotplug
range is the trivially calculated memory-block-size aligned version of the
device range.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hulk Robot <hulkci@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Yan <yanaijie@huawei.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/160106111109.30709.3173462396758431559.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 5bb133d..b0d6a99 100644 (file)
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -19,13 +19,20 @@ static const char *kmem_name;
 /* Set if any memory will remain added when the driver will be unloaded. */
 static bool any_hotremove_failed;
 
+static struct range dax_kmem_range(struct dev_dax *dev_dax)
+{
+       struct range range;
+
+       /* memory-block align the hotplug range */
+       range.start = ALIGN(dev_dax->range.start, memory_block_size_bytes());
+       range.end = ALIGN_DOWN(dev_dax->range.end + 1, memory_block_size_bytes()) - 1;
+       return range;
+}
+
 int dev_dax_kmem_probe(struct device *dev)
 {
        struct dev_dax *dev_dax = to_dev_dax(dev);
-       struct range *range = &dev_dax->range;
-       resource_size_t kmem_start;
-       resource_size_t kmem_size;
-       resource_size_t kmem_end;
+       struct range range = dax_kmem_range(dev_dax);
        struct resource *new_res;
        const char *new_res_name;
        int numa_node;
@@ -44,25 +51,14 @@ int dev_dax_kmem_probe(struct device *dev)
                return -EINVAL;
        }
 
-       /* Hotplug starting at the beginning of the next block: */
-       kmem_start = ALIGN(range->start, memory_block_size_bytes());
-
-       kmem_size = range_len(range);
-       /* Adjust the size down to compensate for moving up kmem_start: */
-       kmem_size -= kmem_start - range->start;
-       /* Align the size down to cover only complete blocks: */
-       kmem_size &= ~(memory_block_size_bytes() - 1);
-       kmem_end = kmem_start + kmem_size;
-
        new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
        if (!new_res_name)
                return -ENOMEM;
 
        /* Region is permanently reserved if hotremove fails. */
-       new_res = request_mem_region(kmem_start, kmem_size, new_res_name);
+       new_res = request_mem_region(range.start, range_len(&range), new_res_name);
        if (!new_res) {
-               dev_warn(dev, "could not reserve region [%pa-%pa]\n",
-                        &kmem_start, &kmem_end);
+               dev_warn(dev, "could not reserve region [%#llx-%#llx]\n", range.start, range.end);
                kfree(new_res_name);
                return -EBUSY;
        }
@@ -96,9 +92,8 @@ int dev_dax_kmem_probe(struct device *dev)
 static int dev_dax_kmem_remove(struct device *dev)
 {
        struct dev_dax *dev_dax = to_dev_dax(dev);
+       struct range range = dax_kmem_range(dev_dax);
        struct resource *res = dev_dax->dax_kmem_res;
-       resource_size_t kmem_start = res->start;
-       resource_size_t kmem_size = resource_size(res);
        const char *res_name = res->name;
        int rc;
 
@@ -108,12 +103,11 @@ static int dev_dax_kmem_remove(struct device *dev)
         * there is no way to hotremove this memory until reboot because device
         * unbind will succeed even if we return failure.
         */
-       rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
+       rc = remove_memory(dev_dax->target_node, range.start, range_len(&range));
        if (rc) {
                any_hotremove_failed = true;
-               dev_err(dev,
-                       "DAX region %pR cannot be hotremoved until the next reboot\n",
-                       res);
+               dev_err(dev, "%#llx-%#llx cannot be hotremoved until the next reboot\n",
+                               range.start, range.end);
                return rc;
        }