memremap: validate the pagemap type passed to devm_memremap_pages

Most pgmap types are only supported when certain config options are
enabled.  Check for a type that is valid for the current configuration
before setting up the pagemap.  For this the usage of the 0 type for
device dax gets replaced with an explicit MEMORY_DEVICE_DEVDAX type.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 8465d12fecba9d3b06c3116ebd7614697becf409..79014baa782d4e00698a15b355fe1a8c1de4d51f 100644 (file)
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -468,6 +468,7 @@ int dev_dax_probe(struct device *dev)
        dev_dax->pgmap.ref = &dev_dax->ref;
        dev_dax->pgmap.kill = dev_dax_percpu_kill;
        dev_dax->pgmap.cleanup = dev_dax_percpu_exit;
+       dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
        addr = devm_memremap_pages(dev, &dev_dax->pgmap);
        if (IS_ERR(addr))
                return PTR_ERR(addr);

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 995c62c5a48b7af9da2d0370bc7abfe386e59384..0c86f2c5ac9c6f10965601089f522f1fc9e4314f 100644 (file)
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -45,13 +45,21 @@ struct vmem_altmap {
  * wakeup is used to coordinate physical address space management (ex:
  * fs truncate/hole punch) vs pinned pages (ex: device dma).
  *
+ * MEMORY_DEVICE_DEVDAX:
+ * Host memory that has similar access semantics as System RAM i.e. DMA
+ * coherent and supports page pinning. In contrast to
+ * MEMORY_DEVICE_FS_DAX, this memory is access via a device-dax
+ * character device.
+ *
  * MEMORY_DEVICE_PCI_P2PDMA:
  * Device memory residing in a PCI BAR intended for use with Peer-to-Peer
  * transactions.
  */
 enum memory_type {
+       /* 0 is reserved to catch uninitialized type fields */
        MEMORY_DEVICE_PRIVATE = 1,
        MEMORY_DEVICE_FS_DAX,
+       MEMORY_DEVICE_DEVDAX,
        MEMORY_DEVICE_PCI_P2PDMA,
 };
 

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 6e1970719dc23dac7a164560883c14ab7b09c50e..abda62d1e5a3bb5d5a05eb6eb4744ff340f7d0d1 100644 (file)
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -157,6 +157,28 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
        pgprot_t pgprot = PAGE_KERNEL;
        int error, nid, is_ram;
 
+       switch (pgmap->type) {
+       case MEMORY_DEVICE_PRIVATE:
+               if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
+                       WARN(1, "Device private memory not supported\n");
+                       return ERR_PTR(-EINVAL);
+               }
+               break;
+       case MEMORY_DEVICE_FS_DAX:
+               if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
+                   IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
+                       WARN(1, "File system DAX not supported\n");
+                       return ERR_PTR(-EINVAL);
+               }
+               break;
+       case MEMORY_DEVICE_DEVDAX:
+       case MEMORY_DEVICE_PCI_P2PDMA:
+               break;
+       default:
+               WARN(1, "Invalid pgmap type %d\n", pgmap->type);
+               break;
+       }
+
        if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) {
                WARN(1, "Missing reference count teardown definition\n");
                return ERR_PTR(-EINVAL);