From: Joao Martins <joao.m.martins@oracle.com>
To: linux-nvdimm@lists.01.org
Cc: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Alex Williamson <alex.williamson@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
kvm@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Liran Alon <liran.alon@oracle.com>,
Nikita Leshenko <nikita.leshchenko@oracle.com>,
Barret Rhoden <brho@google.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Matthew Wilcox <willy@infradead.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH RFC 07/10] device-dax: Add support for PFN_SPECIAL flags
Date: Fri, 10 Jan 2020 19:03:10 +0000 [thread overview]
Message-ID: <20200110190313.17144-8-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20200110190313.17144-1-joao.m.martins@oracle.com>
Right now we assume there's gonna be a PFN_DEV|PFN_MAP which
means it will have a struct page backing the PFN but that is
not placed in normal system RAM zones.
Add support for PFN_DEV|PFN_SPECIAL only and therefore the
underlying vma won't have a struct page. For device dax, this
means not assuming callers will pass a dev_pagemap, and avoid
returning SIGBUS for the lack of PFN_MAP region pfn flag and
finally not setting struct page index/mapping on fault.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
drivers/dax/bus.c | 3 ++-
drivers/dax/device.c | 40 ++++++++++++++++++++++------------------
2 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 46e46047a1f7..96ca3ac85278 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -414,7 +414,8 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
if (!dev_dax)
return ERR_PTR(-ENOMEM);
- memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap));
+ if (pgmap)
+ memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap));
/*
* No 'host' or dax_operations since there is no access to this
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 113a554de3ee..aa38f5ff180a 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -14,6 +14,12 @@
#include "dax-private.h"
#include "bus.h"
+static int dax_is_pfn_special(struct dev_dax *dev_dax)
+{
+ return (dev_dax->region->pfn_flags &
+ (PFN_DEV|PFN_SPECIAL)) == (PFN_DEV|PFN_SPECIAL);
+}
+
static int dax_is_pfn_dev(struct dev_dax *dev_dax)
{
return (dev_dax->region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV;
@@ -104,6 +110,7 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
struct dax_region *dax_region;
phys_addr_t phys;
unsigned int fault_size = PAGE_SIZE;
+ int rc;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
@@ -126,7 +133,12 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
- return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
+ if (dax_is_pfn_special(dev_dax))
+ rc = vmf_insert_pfn(vmf->vma, vmf->address, pfn_t_to_pfn(*pfn));
+ else
+ rc = vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
+
+ return rc;
}
static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
@@ -149,12 +161,6 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
return VM_FAULT_SIGBUS;
}
- /* dax pmd mappings require pfn_t_devmap() */
- if (!dax_is_pfn_map(dev_dax)) {
- dev_dbg(dev, "region lacks devmap flags\n");
- return VM_FAULT_SIGBUS;
- }
-
if (fault_size < dax_region->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dax_region->align)
@@ -199,12 +205,6 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
return VM_FAULT_SIGBUS;
}
- /* dax pud mappings require pfn_t_devmap() */
- if (!dax_is_pfn_map(dev_dax)) {
- dev_dbg(dev, "region lacks devmap flags\n");
- return VM_FAULT_SIGBUS;
- }
-
if (fault_size < dax_region->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dax_region->align)
@@ -266,7 +266,7 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
rc = VM_FAULT_SIGBUS;
}
- if (rc == VM_FAULT_NOPAGE) {
+ if (dax_is_pfn_map(dev_dax) && (rc == VM_FAULT_NOPAGE)) {
unsigned long i;
pgoff_t pgoff;
@@ -344,6 +344,8 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
vma->vm_ops = &dax_vm_ops;
vma->vm_flags |= VM_HUGEPAGE;
+ if (dax_is_pfn_special(dev_dax))
+ vma->vm_flags |= VM_PFNMAP;
return 0;
}
@@ -450,10 +452,12 @@ int dev_dax_probe(struct device *dev)
return -EBUSY;
}
- dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
- addr = devm_memremap_pages(dev, &dev_dax->pgmap);
- if (IS_ERR(addr))
- return PTR_ERR(addr);
+ if (dax_is_pfn_map(dev_dax)) {
+ dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
+ addr = devm_memremap_pages(dev, &dev_dax->pgmap);
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
+ }
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
--
2.17.1
next prev parent reply other threads:[~2020-01-10 19:05 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 19:03 [PATCH RFC 00/10] device-dax: Support devices without PFN metadata Joao Martins
2020-01-10 19:03 ` [PATCH RFC 01/10] mm: Add pmd support for _PAGE_SPECIAL Joao Martins
2020-02-03 21:34 ` Matthew Wilcox
2020-02-04 16:14 ` Joao Martins
2020-01-10 19:03 ` [PATCH RFC 02/10] mm: Handle pmd entries in follow_pfn() Joao Martins
2020-02-03 21:37 ` Matthew Wilcox
2020-02-04 16:17 ` Joao Martins
2020-01-10 19:03 ` [PATCH RFC 03/10] mm: Add pud support for _PAGE_SPECIAL Joao Martins
2020-01-10 19:03 ` [PATCH RFC 04/10] mm: Handle pud entries in follow_pfn() Joao Martins
2020-01-10 19:03 ` [PATCH RFC 05/10] device-dax: Do not enforce MADV_DONTFORK on mmap() Joao Martins
2020-01-10 19:03 ` [PATCH RFC 06/10] device-dax: Introduce pfn_flags helper Joao Martins
2020-01-10 19:03 ` Joao Martins [this message]
2020-01-10 19:03 ` [PATCH RFC 08/10] dax/pmem: Add device-dax support for PFN_MODE_NONE Joao Martins
2020-01-10 19:03 ` [PATCH RFC 09/10] vfio/type1: Use follow_pfn for VM_FPNMAP VMAs Joao Martins
2020-02-07 21:08 ` Jason Gunthorpe
2020-02-11 16:23 ` Joao Martins
2020-02-11 16:50 ` Jason Gunthorpe
2020-01-10 19:03 ` [PATCH RFC 10/10] nvdimm/e820: add multiple namespaces support Joao Martins
2020-02-04 15:28 ` Barret Rhoden
2020-02-04 16:44 ` Dan Williams
2020-02-04 18:20 ` Barret Rhoden
2020-02-04 19:24 ` Joao Martins
2020-02-04 21:43 ` Dan Williams
2020-02-04 21:57 ` Barret Rhoden
2020-02-04 1:24 ` [PATCH RFC 00/10] device-dax: Support devices without PFN metadata Dan Williams
2020-02-04 19:07 ` Joao Martins
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