[v4,02/12] device-dax: Cleanup vm_fault de-reference chains

Message ID	152850183221.38390.15042297366983937566.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> Subject: [PATCH v4 02/12] device-dax: Cleanup vm_fault de-reference chains From: Dan Williams <dan.j.williams@intel.com> To: linux-nvdimm@lists.01.org Cc: hch@lst.de, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, jack@suse.cz Date: Fri, 08 Jun 2018 16:50:32 -0700 Message-ID: <152850183221.38390.15042297366983937566.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk

Message ID

152850183221.38390.15042297366983937566.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive)

State

New, archived

Headers

Subject: [PATCH v4 02/12] device-dax: Cleanup vm_fault de-reference chains
From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: hch@lst.de, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	jack@suse.cz
Date: Fri, 08 Jun 2018 16:50:32 -0700
Message-ID: <152850183221.38390.15042297366983937566.stgit@dwillia2-desk3.amr.corp.intel.com>
In-Reply-To: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com>
References: <152850182079.38390.8280340535691965744.stgit@dwillia2-desk3.amr.corp.intel.com>
User-Agent: StGit/0.18-2-gc94f
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Sender: linux-fsdevel-owner@vger.kernel.org
Precedence: bulk

Commit Message

Dan Williams June 8, 2018, 11:50 p.m. UTC

Define a local 'vma' variable rather than repetitively de-referencing
the passed in 'struct vm_fault *' instance.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/dax/device.c |   30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

Comments

Laurent Dufour June 11, 2018, 5:12 p.m. UTC | #1

On 09/06/2018 01:50, Dan Williams wrote:
> Define a local 'vma' variable rather than repetitively de-referencing
> the passed in 'struct vm_fault *' instance.

Hi Dan,

Why is this needed ?

I can't see the real benefit, having the vma deferenced from the vm_fault
structure is not obfuscating the code and it eases to follow the use of vmf->vma.

Am I missing something ?

Cheers,
Laurent.

> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/dax/device.c |   30 ++++++++++++++++--------------
>  1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> index d44d98c54d0f..686de08e120b 100644
> --- a/drivers/dax/device.c
> +++ b/drivers/dax/device.c
> @@ -247,13 +247,14 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
>  static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
>  				struct vm_fault *vmf)
>  {
> +	struct vm_area_struct *vma = vmf->vma;
>  	struct device *dev = &dev_dax->dev;
>  	struct dax_region *dax_region;
>  	phys_addr_t phys;
>  	pfn_t pfn;
>  	unsigned int fault_size = PAGE_SIZE;
> 
> -	if (check_vma(dev_dax, vmf->vma, __func__))
> +	if (check_vma(dev_dax, vma, __func__))
>  		return VM_FAULT_SIGBUS;
> 
>  	dax_region = dev_dax->region;
> @@ -274,13 +275,14 @@ 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);
> +	return vmf_insert_mixed(vma, vmf->address, pfn);
>  }
> 
>  static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
>  				struct vm_fault *vmf)
>  {
>  	unsigned long pmd_addr = vmf->address & PMD_MASK;
> +	struct vm_area_struct *vma = vmf->vma;
>  	struct device *dev = &dev_dax->dev;
>  	struct dax_region *dax_region;
>  	phys_addr_t phys;
> @@ -288,7 +290,7 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
>  	pfn_t pfn;
>  	unsigned int fault_size = PMD_SIZE;
> 
> -	if (check_vma(dev_dax, vmf->vma, __func__))
> +	if (check_vma(dev_dax, vma, __func__))
>  		return VM_FAULT_SIGBUS;
> 
>  	dax_region = dev_dax->region;
> @@ -310,11 +312,10 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
>  		return VM_FAULT_FALLBACK;
> 
>  	/* if we are outside of the VMA */
> -	if (pmd_addr < vmf->vma->vm_start ||
> -			(pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
> +	if (pmd_addr < vma->vm_start || (pmd_addr + PMD_SIZE) > vma->vm_end)
>  		return VM_FAULT_SIGBUS;
> 
> -	pgoff = linear_page_index(vmf->vma, pmd_addr);
> +	pgoff = linear_page_index(vma, pmd_addr);
>  	phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
>  	if (phys == -1) {
>  		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
> @@ -323,7 +324,7 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
> 
>  	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
> 
> -	return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, pfn,
> +	return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn,
>  			vmf->flags & FAULT_FLAG_WRITE);
>  }
> 
> @@ -332,6 +333,7 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
>  				struct vm_fault *vmf)
>  {
>  	unsigned long pud_addr = vmf->address & PUD_MASK;
> +	struct vm_area_struct *vma = vmf->vma;
>  	struct device *dev = &dev_dax->dev;
>  	struct dax_region *dax_region;
>  	phys_addr_t phys;
> @@ -340,7 +342,7 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
>  	unsigned int fault_size = PUD_SIZE;
> 
> 
> -	if (check_vma(dev_dax, vmf->vma, __func__))
> +	if (check_vma(dev_dax, vma, __func__))
>  		return VM_FAULT_SIGBUS;
> 
>  	dax_region = dev_dax->region;
> @@ -362,11 +364,10 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
>  		return VM_FAULT_FALLBACK;
> 
>  	/* if we are outside of the VMA */
> -	if (pud_addr < vmf->vma->vm_start ||
> -			(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
> +	if (pud_addr < vma->vm_start || (pud_addr + PUD_SIZE) > vma->vm_end)
>  		return VM_FAULT_SIGBUS;
> 
> -	pgoff = linear_page_index(vmf->vma, pud_addr);
> +	pgoff = linear_page_index(vma, pud_addr);
>  	phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
>  	if (phys == -1) {
>  		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
> @@ -375,7 +376,7 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
> 
>  	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
> 
> -	return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, pfn,
> +	return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, pfn,
>  			vmf->flags & FAULT_FLAG_WRITE);
>  }
>  #else
> @@ -390,12 +391,13 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
>  		enum page_entry_size pe_size)
>  {
>  	int rc, id;
> -	struct file *filp = vmf->vma->vm_file;
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct file *filp = vma->vm_file;
>  	struct dev_dax *dev_dax = filp->private_data;
> 
>  	dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
>  			(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
> -			vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
> +			vma->vm_start, vma->vm_end, pe_size);
> 
>  	id = dax_read_lock();
>  	switch (pe_size) {
>

Dan Williams June 11, 2018, 5:14 p.m. UTC | #2

On Mon, Jun 11, 2018 at 10:12 AM, Laurent Dufour
<ldufour@linux.vnet.ibm.com> wrote:
> On 09/06/2018 01:50, Dan Williams wrote:
>> Define a local 'vma' variable rather than repetitively de-referencing
>> the passed in 'struct vm_fault *' instance.
>
> Hi Dan,
>
> Why is this needed ?
>
> I can't see the real benefit, having the vma deferenced from the vm_fault
> structure is not obfuscating the code and it eases to follow the use of vmf->vma.
>
> Am I missing something ?

No, and now that I take another look it's just noise. I'll drop it.

Thanks for the poke.

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index d44d98c54d0f..686de08e120b 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -247,13 +247,14 @@  __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
 static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
 				struct vm_fault *vmf)
 {
+	struct vm_area_struct *vma = vmf->vma;
 	struct device *dev = &dev_dax->dev;
 	struct dax_region *dax_region;
 	phys_addr_t phys;
 	pfn_t pfn;
 	unsigned int fault_size = PAGE_SIZE;
 
-	if (check_vma(dev_dax, vmf->vma, __func__))
+	if (check_vma(dev_dax, vma, __func__))
 		return VM_FAULT_SIGBUS;
 
 	dax_region = dev_dax->region;
@@ -274,13 +275,14 @@  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);
+	return vmf_insert_mixed(vma, vmf->address, pfn);
 }
 
 static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
 				struct vm_fault *vmf)
 {
 	unsigned long pmd_addr = vmf->address & PMD_MASK;
+	struct vm_area_struct *vma = vmf->vma;
 	struct device *dev = &dev_dax->dev;
 	struct dax_region *dax_region;
 	phys_addr_t phys;
@@ -288,7 +290,7 @@  static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
 	pfn_t pfn;
 	unsigned int fault_size = PMD_SIZE;
 
-	if (check_vma(dev_dax, vmf->vma, __func__))
+	if (check_vma(dev_dax, vma, __func__))
 		return VM_FAULT_SIGBUS;
 
 	dax_region = dev_dax->region;
@@ -310,11 +312,10 @@  static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
 		return VM_FAULT_FALLBACK;
 
 	/* if we are outside of the VMA */
-	if (pmd_addr < vmf->vma->vm_start ||
-			(pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
+	if (pmd_addr < vma->vm_start || (pmd_addr + PMD_SIZE) > vma->vm_end)
 		return VM_FAULT_SIGBUS;
 
-	pgoff = linear_page_index(vmf->vma, pmd_addr);
+	pgoff = linear_page_index(vma, pmd_addr);
 	phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
 	if (phys == -1) {
 		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
@@ -323,7 +324,7 @@  static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
 
 	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
 
-	return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, pfn,
+	return vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn,
 			vmf->flags & FAULT_FLAG_WRITE);
 }
 
@@ -332,6 +333,7 @@  static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
 				struct vm_fault *vmf)
 {
 	unsigned long pud_addr = vmf->address & PUD_MASK;
+	struct vm_area_struct *vma = vmf->vma;
 	struct device *dev = &dev_dax->dev;
 	struct dax_region *dax_region;
 	phys_addr_t phys;
@@ -340,7 +342,7 @@  static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
 	unsigned int fault_size = PUD_SIZE;
 
 
-	if (check_vma(dev_dax, vmf->vma, __func__))
+	if (check_vma(dev_dax, vma, __func__))
 		return VM_FAULT_SIGBUS;
 
 	dax_region = dev_dax->region;
@@ -362,11 +364,10 @@  static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
 		return VM_FAULT_FALLBACK;
 
 	/* if we are outside of the VMA */
-	if (pud_addr < vmf->vma->vm_start ||
-			(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
+	if (pud_addr < vma->vm_start || (pud_addr + PUD_SIZE) > vma->vm_end)
 		return VM_FAULT_SIGBUS;
 
-	pgoff = linear_page_index(vmf->vma, pud_addr);
+	pgoff = linear_page_index(vma, pud_addr);
 	phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
 	if (phys == -1) {
 		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
@@ -375,7 +376,7 @@  static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
 
 	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
 
-	return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, pfn,
+	return vmf_insert_pfn_pud(vma, vmf->address, vmf->pud, pfn,
 			vmf->flags & FAULT_FLAG_WRITE);
 }
 #else
@@ -390,12 +391,13 @@  static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
 		enum page_entry_size pe_size)
 {
 	int rc, id;
-	struct file *filp = vmf->vma->vm_file;
+	struct vm_area_struct *vma = vmf->vma;
+	struct file *filp = vma->vm_file;
 	struct dev_dax *dev_dax = filp->private_data;
 
 	dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
 			(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
-			vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
+			vma->vm_start, vma->vm_end, pe_size);
 
 	id = dax_read_lock();
 	switch (pe_size) {

[v4,02/12] device-dax: Cleanup vm_fault de-reference chains

Commit Message

Comments

Patch