From: Joao Martins <joao.m.martins@oracle.com> To: linux-nvdimm@lists.01.org Cc: 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 05/10] device-dax: Do not enforce MADV_DONTFORK on mmap() Date: Fri, 10 Jan 2020 19:03:08 +0000 [thread overview] Message-ID: <20200110190313.17144-6-joao.m.martins@oracle.com> (raw) In-Reply-To: <20200110190313.17144-1-joao.m.martins@oracle.com> Currently check_vma() checks for VM_DONTCOPY for a device-dax when the dax region is not backed by devmap (i.e. PFN_MAP is not set). VM_DONTCOPY is set through madvise(MADV_DONTFORK) and it only sets it at an address returned from mmap(). check_vma() is called at devdax mmap hence checking VM_DONTCOPY prevents a process from mmap-ing the device. Let's not enforce MADV_DONTFORK at mmap(), but rather when it actually gets used (on fault). The assumptions don't change, as it is expected to still retain/madvise MADV_DONTFORK after mmap. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- drivers/dax/device.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 1af823b2fe6b..c6a7f5e12c54 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -14,7 +14,7 @@ #include "dax-private.h" #include "bus.h" -static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, +static int check_vma_mmap(struct dev_dax *dev_dax, struct vm_area_struct *vma, const char *func) { struct dax_region *dax_region = dev_dax->region; @@ -41,17 +41,29 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, return -EINVAL; } - if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV - && (vma->vm_flags & VM_DONTCOPY) == 0) { + if (!vma_is_dax(vma)) { dev_info_ratelimited(dev, - "%s: %s: fail, dax range requires MADV_DONTFORK\n", + "%s: %s: fail, vma is not DAX capable\n", current->comm, func); return -EINVAL; } - if (!vma_is_dax(vma)) { - dev_info_ratelimited(dev, - "%s: %s: fail, vma is not DAX capable\n", + return 0; +} + +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, + const char *func) +{ + int rc; + + rc = check_vma_mmap(dev_dax, vma, func); + if (rc < 0) + return rc; + + if ((dev_dax->region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV + && (vma->vm_flags & VM_DONTCOPY) == 0) { + dev_info_ratelimited(&dev_dax->dev, + "%s: %s: fail, dax range requires MADV_DONTFORK\n", current->comm, func); return -EINVAL; } @@ -315,7 +327,7 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) * fault time. */ id = dax_read_lock(); - rc = check_vma(dev_dax, vma, __func__); + rc = check_vma_mmap(dev_dax, vma, __func__); dax_read_unlock(id); if (rc) return rc; -- 2.17.1 _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
WARNING: multiple messages have this Message-ID (diff)
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 05/10] device-dax: Do not enforce MADV_DONTFORK on mmap() Date: Fri, 10 Jan 2020 19:03:08 +0000 [thread overview] Message-ID: <20200110190313.17144-6-joao.m.martins@oracle.com> (raw) In-Reply-To: <20200110190313.17144-1-joao.m.martins@oracle.com> Currently check_vma() checks for VM_DONTCOPY for a device-dax when the dax region is not backed by devmap (i.e. PFN_MAP is not set). VM_DONTCOPY is set through madvise(MADV_DONTFORK) and it only sets it at an address returned from mmap(). check_vma() is called at devdax mmap hence checking VM_DONTCOPY prevents a process from mmap-ing the device. Let's not enforce MADV_DONTFORK at mmap(), but rather when it actually gets used (on fault). The assumptions don't change, as it is expected to still retain/madvise MADV_DONTFORK after mmap. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- drivers/dax/device.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 1af823b2fe6b..c6a7f5e12c54 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -14,7 +14,7 @@ #include "dax-private.h" #include "bus.h" -static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, +static int check_vma_mmap(struct dev_dax *dev_dax, struct vm_area_struct *vma, const char *func) { struct dax_region *dax_region = dev_dax->region; @@ -41,17 +41,29 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, return -EINVAL; } - if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV - && (vma->vm_flags & VM_DONTCOPY) == 0) { + if (!vma_is_dax(vma)) { dev_info_ratelimited(dev, - "%s: %s: fail, dax range requires MADV_DONTFORK\n", + "%s: %s: fail, vma is not DAX capable\n", current->comm, func); return -EINVAL; } - if (!vma_is_dax(vma)) { - dev_info_ratelimited(dev, - "%s: %s: fail, vma is not DAX capable\n", + return 0; +} + +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, + const char *func) +{ + int rc; + + rc = check_vma_mmap(dev_dax, vma, func); + if (rc < 0) + return rc; + + if ((dev_dax->region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV + && (vma->vm_flags & VM_DONTCOPY) == 0) { + dev_info_ratelimited(&dev_dax->dev, + "%s: %s: fail, dax range requires MADV_DONTFORK\n", current->comm, func); return -EINVAL; } @@ -315,7 +327,7 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) * fault time. */ id = dax_read_lock(); - rc = check_vma(dev_dax, vma, __func__); + rc = check_vma_mmap(dev_dax, vma, __func__); dax_read_unlock(id); if (rc) return rc; -- 2.17.1
next prev parent reply other threads:[~2020-01-10 19:06 UTC|newest] Thread overview: 53+ 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 ` Joao Martins 2020-01-10 19:03 ` [PATCH RFC 01/10] mm: Add pmd support for _PAGE_SPECIAL Joao Martins 2020-01-10 19:03 ` Joao Martins 2020-02-03 21:34 ` Matthew Wilcox 2020-02-03 21:34 ` Matthew Wilcox 2020-02-04 16:14 ` Joao Martins 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 2020-01-10 19:03 ` Joao Martins 2020-02-03 21:37 ` Matthew Wilcox 2020-02-03 21:37 ` Matthew Wilcox 2020-02-04 16:17 ` Joao Martins 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 ` 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 ` Joao Martins 2020-01-10 19:03 ` Joao Martins [this message] 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 2020-01-10 19:03 ` [PATCH RFC 07/10] device-dax: Add support for PFN_SPECIAL flags Joao Martins 2020-01-10 19:03 ` Joao Martins 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 ` Joao Martins 2020-01-10 19:03 ` [PATCH RFC 09/10] vfio/type1: Use follow_pfn for VM_FPNMAP VMAs Joao Martins 2020-01-10 19:03 ` Joao Martins 2020-02-07 21:08 ` Jason Gunthorpe 2020-02-11 16:23 ` Joao Martins 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 2020-01-10 19:03 ` Joao Martins 2020-02-04 15:28 ` Barret Rhoden 2020-02-04 15:28 ` Barret Rhoden 2020-02-04 16:44 ` Dan Williams 2020-02-04 16:44 ` Dan Williams 2020-02-04 16:44 ` Dan Williams 2020-02-04 18:20 ` Barret Rhoden 2020-02-04 18:20 ` Barret Rhoden 2020-02-04 19:24 ` Joao Martins 2020-02-04 19:24 ` Joao Martins 2020-02-04 21:43 ` Dan Williams 2020-02-04 21:43 ` Dan Williams 2020-02-04 21:43 ` Dan Williams 2020-02-04 21:57 ` Barret Rhoden 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 1:24 ` Dan Williams 2020-02-04 1:24 ` Dan Williams 2020-02-04 19:07 ` Joao Martins 2020-02-04 19:07 ` Joao Martins
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