PMEM: Introduce stray write protection for PMEM

[PATCH RFC PKS/PMEM 51/58] kernel: Utilize new kmap_thread()

ira.weiny@intel.com posted 58 patches 5 years, 4 months ago

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[PATCH RFC PKS/PMEM 51/58] kernel: Utilize new kmap_thread()

Posted by ira.weiny@intel.com 5 years, 4 months ago

From: Ira Weiny <ira.weiny@intel.com>

This kmap() call is localized to a single thread.  To avoid the over
head of global PKRS updates use the new kmap_thread() call.

Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 kernel/kexec_core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c19c0dad1ebe..272a9920c0d6 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -815,7 +815,7 @@ static int kimage_load_normal_segment(struct kimage *image,
 		if (result < 0)
 			goto out;
 
-		ptr = kmap(page);
+		ptr = kmap_thread(page);
 		/* Start with a clear page */
 		clear_page(ptr);
 		ptr += maddr & ~PAGE_MASK;
@@ -828,7 +828,7 @@ static int kimage_load_normal_segment(struct kimage *image,
 			memcpy(ptr, kbuf, uchunk);
 		else
 			result = copy_from_user(ptr, buf, uchunk);
-		kunmap(page);
+		kunmap_thread(page);
 		if (result) {
 			result = -EFAULT;
 			goto out;
@@ -879,7 +879,7 @@ static int kimage_load_crash_segment(struct kimage *image,
 			goto out;
 		}
 		arch_kexec_post_alloc_pages(page_address(page), 1, 0);
-		ptr = kmap(page);
+		ptr = kmap_thread(page);
 		ptr += maddr & ~PAGE_MASK;
 		mchunk = min_t(size_t, mbytes,
 				PAGE_SIZE - (maddr & ~PAGE_MASK));
@@ -895,7 +895,7 @@ static int kimage_load_crash_segment(struct kimage *image,
 		else
 			result = copy_from_user(ptr, buf, uchunk);
 		kexec_flush_icache_page(page);
-		kunmap(page);
+		kunmap_thread(page);
 		arch_kexec_pre_free_pages(page_address(page), 1);
 		if (result) {
 			result = -EFAULT;
-- 
2.28.0.rc0.12.gb6a658bd00c9

Re: [PATCH RFC PKS/PMEM 51/58] kernel: Utilize new kmap_thread()

Posted by Eric W. Biederman 5 years, 4 months ago

ira.weiny@intel.com writes:

> From: Ira Weiny <ira.weiny@intel.com>
>
> This kmap() call is localized to a single thread.  To avoid the over
> head of global PKRS updates use the new kmap_thread() call.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>

>
> Cc: Eric Biederman <ebiederm@xmission.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
>  kernel/kexec_core.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index c19c0dad1ebe..272a9920c0d6 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -815,7 +815,7 @@ static int kimage_load_normal_segment(struct kimage *image,
>  		if (result < 0)
>  			goto out;
>  
> -		ptr = kmap(page);
> +		ptr = kmap_thread(page);
>  		/* Start with a clear page */
>  		clear_page(ptr);
>  		ptr += maddr & ~PAGE_MASK;
> @@ -828,7 +828,7 @@ static int kimage_load_normal_segment(struct kimage *image,
>  			memcpy(ptr, kbuf, uchunk);
>  		else
>  			result = copy_from_user(ptr, buf, uchunk);
> -		kunmap(page);
> +		kunmap_thread(page);
>  		if (result) {
>  			result = -EFAULT;
>  			goto out;
> @@ -879,7 +879,7 @@ static int kimage_load_crash_segment(struct kimage *image,
>  			goto out;
>  		}
>  		arch_kexec_post_alloc_pages(page_address(page), 1, 0);
> -		ptr = kmap(page);
> +		ptr = kmap_thread(page);
>  		ptr += maddr & ~PAGE_MASK;
>  		mchunk = min_t(size_t, mbytes,
>  				PAGE_SIZE - (maddr & ~PAGE_MASK));
> @@ -895,7 +895,7 @@ static int kimage_load_crash_segment(struct kimage *image,
>  		else
>  			result = copy_from_user(ptr, buf, uchunk);
>  		kexec_flush_icache_page(page);
> -		kunmap(page);
> +		kunmap_thread(page);
>  		arch_kexec_pre_free_pages(page_address(page), 1);
>  		if (result) {
>  			result = -EFAULT;