From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Theodore Ts'o <tytso@mit.edu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
Dave Chinner <david@fromorbit.com>,
David Airlie <airlied@linux.ie>, Ingo Molnar <mingo@redhat.com>,
Inki Dae <inki.dae@samsung.com>, Jan Kara <jack@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
Joonyoung Shim <jy0922.shim@samsung.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Kukjin Kim <kgene@kernel.org>,
Kyungmin Park <kyungmin.park@samsung.com>,
Matthew Wilcox <mawilcox@microsoft.com>,
Patrik Jakobsson <patrik.r.jakobsson@gmail.com>,
Rob Clark <robdclark@gmail.com>,
Seung-Woo Kim <sw0312.kim@samsung.com>,
Steven Rostedt <rostedt@goodmis.org>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org, linux-doc@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nvdimm@lists.01.org,
linux-samsung-soc@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: [PATCH v4 1/5] mm: add mkwrite param to vm_insert_mixed()
Date: Fri, 21 Jul 2017 16:39:51 -0600 [thread overview]
Message-ID: <20170721223956.29485-2-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <20170721223956.29485-1-ross.zwisler@linux.intel.com>
To be able to use the common 4k zero page in DAX we need to have our PTE
fault path look more like our PMD fault path where a PTE entry can be
marked as dirty and writeable as it is first inserted, rather than waiting
for a follow-up dax_pfn_mkwrite() => finish_mkwrite_fault() call.
Right now we can rely on having a dax_pfn_mkwrite() call because we can
distinguish between these two cases in do_wp_page():
case 1: 4k zero page => writable DAX storage
case 2: read-only DAX storage => writeable DAX storage
This distinction is made by via vm_normal_page(). vm_normal_page() returns
false for the common 4k zero page, though, just as it does for DAX ptes.
Instead of special casing the DAX + 4k zero page case, we will simplify our
DAX PTE page fault sequence so that it matches our DAX PMD sequence, and
get rid of the dax_pfn_mkwrite() helper. We will instead use
dax_iomap_fault() to handle write-protection faults.
This means that insert_pfn() needs to follow the lead of insert_pfn_pmd()
and allow us to pass in a 'mkwrite' flag. If 'mkwrite' is set insert_pfn()
will do the work that was previously done by wp_page_reuse() as part of the
dax_pfn_mkwrite() call path.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
drivers/dax/device.c | 2 +-
drivers/gpu/drm/exynos/exynos_drm_gem.c | 3 ++-
drivers/gpu/drm/gma500/framebuffer.c | 2 +-
drivers/gpu/drm/msm/msm_gem.c | 3 ++-
drivers/gpu/drm/omapdrm/omap_gem.c | 6 ++++--
drivers/gpu/drm/ttm/ttm_bo_vm.c | 2 +-
fs/dax.c | 2 +-
include/linux/mm.h | 2 +-
mm/memory.c | 27 +++++++++++++++++++++------
9 files changed, 34 insertions(+), 15 deletions(-)
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index e9f3b3e..3973521 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -273,7 +273,7 @@ static int __dev_dax_pte_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
- rc = vm_insert_mixed(vmf->vma, vmf->address, pfn);
+ rc = vm_insert_mixed(vmf->vma, vmf->address, pfn, false);
if (rc == -ENOMEM)
return VM_FAULT_OOM;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index c23479b..bfa6648 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -466,7 +466,8 @@ int exynos_drm_gem_fault(struct vm_fault *vmf)
}
pfn = page_to_pfn(exynos_gem->pages[page_offset]);
- ret = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
+ ret = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV),
+ false);
out:
switch (ret) {
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 7da70b6..6dd865f 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -134,7 +134,7 @@ static int psbfb_vm_fault(struct vm_fault *vmf)
pfn = (phys_addr >> PAGE_SHIFT);
ret = vm_insert_mixed(vma, address,
- __pfn_to_pfn_t(pfn, PFN_DEV));
+ __pfn_to_pfn_t(pfn, PFN_DEV), false);
if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
break;
else if (unlikely(ret != 0)) {
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 65f3554..c187fd1 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -249,7 +249,8 @@ int msm_gem_fault(struct vm_fault *vmf)
VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
pfn, pfn << PAGE_SHIFT);
- ret = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
+ ret = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV),
+ false);
out_unlock:
mutex_unlock(&msm_obj->lock);
diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index 5c5c86d..26eebcd 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -393,7 +393,8 @@ static int fault_1d(struct drm_gem_object *obj,
VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
pfn, pfn << PAGE_SHIFT);
- return vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
+ return vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV),
+ false);
}
/* Special handling for the case of faulting in 2d tiled buffers */
@@ -486,7 +487,8 @@ static int fault_2d(struct drm_gem_object *obj,
pfn, pfn << PAGE_SHIFT);
for (i = n; i > 0; i--) {
- vm_insert_mixed(vma, vaddr, __pfn_to_pfn_t(pfn, PFN_DEV));
+ vm_insert_mixed(vma, vaddr, __pfn_to_pfn_t(pfn, PFN_DEV),
+ false);
pfn += priv->usergart[fmt].stride_pfn;
vaddr += PAGE_SIZE * m;
}
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index b442d12..e85bfa7 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -248,7 +248,7 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf)
if (vma->vm_flags & VM_MIXEDMAP)
ret = vm_insert_mixed(&cvma, address,
- __pfn_to_pfn_t(pfn, PFN_DEV));
+ __pfn_to_pfn_t(pfn, PFN_DEV), false);
else
ret = vm_insert_pfn(&cvma, address, pfn);
diff --git a/fs/dax.c b/fs/dax.c
index 306c2b6..c844a51 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -899,7 +899,7 @@ static int dax_insert_mapping(struct address_space *mapping,
*entryp = ret;
trace_dax_insert_mapping(mapping->host, vmf, ret);
- return vm_insert_mixed(vma, vaddr, pfn);
+ return vm_insert_mixed(vma, vaddr, pfn, false);
}
/**
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 46b9ac5..3eabc40 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2292,7 +2292,7 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, pgprot_t pgprot);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn);
+ pfn_t pfn, bool mkwrite);
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
diff --git a/mm/memory.c b/mm/memory.c
index 0e517be..d351911 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1646,7 +1646,7 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
EXPORT_SYMBOL(vm_insert_page);
static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn, pgprot_t prot)
+ pfn_t pfn, pgprot_t prot, bool mkwrite)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
@@ -1658,14 +1658,28 @@ static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
if (!pte)
goto out;
retval = -EBUSY;
- if (!pte_none(*pte))
- goto out_unlock;
+ if (!pte_none(*pte)) {
+ if (mkwrite) {
+ if (WARN_ON_ONCE(pte_pfn(*pte) != pfn_t_to_pfn(pfn)))
+ goto out_unlock;
+ entry = *pte;
+ goto out_mkwrite;
+ } else
+ goto out_unlock;
+ }
/* Ok, finally just insert the thing.. */
if (pfn_t_devmap(pfn))
entry = pte_mkdevmap(pfn_t_pte(pfn, prot));
else
entry = pte_mkspecial(pfn_t_pte(pfn, prot));
+
+out_mkwrite:
+ if (mkwrite) {
+ entry = pte_mkyoung(entry);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ }
+
set_pte_at(mm, addr, pte, entry);
update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
@@ -1736,14 +1750,15 @@ int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV));
- ret = insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot);
+ ret = insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot,
+ false);
return ret;
}
EXPORT_SYMBOL(vm_insert_pfn_prot);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn)
+ pfn_t pfn, bool mkwrite)
{
pgprot_t pgprot = vma->vm_page_prot;
@@ -1772,7 +1787,7 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
page = pfn_to_page(pfn_t_to_pfn(pfn));
return insert_page(vma, addr, page, pgprot);
}
- return insert_pfn(vma, addr, pfn, pgprot);
+ return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
}
EXPORT_SYMBOL(vm_insert_mixed);
--
2.9.4
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next prev parent reply other threads:[~2017-07-21 22:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-21 22:39 [PATCH v4 0/5] DAX common 4k zero page Ross Zwisler
2017-07-21 22:39 ` Ross Zwisler [this message]
2017-07-22 16:21 ` [PATCH v4 1/5] mm: add mkwrite param to vm_insert_mixed() Dan Williams
2017-07-24 11:15 ` Jan Kara
2017-07-24 15:13 ` Ross Zwisler
2017-07-24 11:25 ` Jan Kara
2017-07-24 15:23 ` Ross Zwisler
2017-07-24 15:59 ` Jan Kara
2017-07-21 22:39 ` [PATCH v4 2/5] dax: relocate some dax functions Ross Zwisler
2017-07-24 11:35 ` Jan Kara
2017-07-21 22:39 ` [PATCH v4 3/5] dax: use common 4k zero page for dax mmap reads Ross Zwisler
2017-07-24 11:46 ` Jan Kara
2017-07-21 22:39 ` [PATCH v4 4/5] dax: remove DAX code from page_cache_tree_insert() Ross Zwisler
2017-07-24 11:47 ` Jan Kara
2017-07-21 22:39 ` [PATCH v4 5/5] dax: move all DAX radix tree defs to fs/dax.c Ross Zwisler
2017-07-24 11:48 ` Jan Kara
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