[01/13] amdgpu: remove -EAGAIN handling for hmm_range_fault

Submitted by Christoph Hellwig on July 30, 2019, 5:51 a.m.

Details

Message ID 20190730055203.28467-2-hch@lst.de
State New
Headers show
Series "Series without cover letter" ( rev: 1 ) in AMD X.Org drivers

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Commit Message

Christoph Hellwig July 30, 2019, 5:51 a.m.
hmm_range_fault can only return -EAGAIN if called with the block
argument set to false, so remove the special handling for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

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diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 12a59ac83f72..f0821638bbc6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -778,7 +778,6 @@  int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 	struct hmm_range *range;
 	unsigned long i;
 	uint64_t *pfns;
-	int retry = 0;
 	int r = 0;
 
 	if (!mm) /* Happens during process shutdown */
@@ -822,7 +821,6 @@  int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 	hmm_range_register(range, mirror, start,
 			   start + ttm->num_pages * PAGE_SIZE, PAGE_SHIFT);
 
-retry:
 	/*
 	 * Just wait for range to be valid, safe to ignore return value as we
 	 * will use the return value of hmm_range_fault() below under the
@@ -831,24 +829,12 @@  int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 	hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT);
 
 	down_read(&mm->mmap_sem);
-
 	r = hmm_range_fault(range, 0);
-	if (unlikely(r < 0)) {
-		if (likely(r == -EAGAIN)) {
-			/*
-			 * return -EAGAIN, mmap_sem is dropped
-			 */
-			if (retry++ < MAX_RETRY_HMM_RANGE_FAULT)
-				goto retry;
-			else
-				pr_err("Retry hmm fault too many times\n");
-		}
-
-		goto out_up_read;
-	}
-
 	up_read(&mm->mmap_sem);
 
+	if (unlikely(r < 0))
+		goto out_free_pfns;
+
 	for (i = 0; i < ttm->num_pages; i++) {
 		pages[i] = hmm_device_entry_to_page(range, pfns[i]);
 		if (unlikely(!pages[i])) {
@@ -864,9 +850,6 @@  int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 
 	return 0;
 
-out_up_read:
-	if (likely(r != -EAGAIN))
-		up_read(&mm->mmap_sem);
 out_free_pfns:
 	hmm_range_unregister(range);
 	kvfree(pfns);

Comments

On Tue, Jul 30, 2019 at 08:51:51AM +0300, Christoph Hellwig wrote:
> hmm_range_fault can only return -EAGAIN if called with the block
> argument set to false, so remove the special handling for it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 23 +++--------------------
>  1 file changed, 3 insertions(+), 20 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>

Jason
On 2019-07-30 1:51 a.m., Christoph Hellwig wrote:
> hmm_range_fault can only return -EAGAIN if called with the block

> argument set to false, so remove the special handling for it.


The block argument no longer exists. You replaced that with the 
HMM_FAULT_ALLOW_RETRY with opposite logic. So this should read 
"hmm_range_fault can only return -EAGAIN if called with the 
HMM_FAULT_ALLOW_RETRY flag set, so remove the special handling for it.

With that fixed, this commit is Reviewed-by: Felix Kuehling 
<Felix.Kuehling@amd.com>

>

> Signed-off-by: Christoph Hellwig <hch@lst.de>

> ---

>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 23 +++--------------------

>   1 file changed, 3 insertions(+), 20 deletions(-)

>

> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

> index 12a59ac83f72..f0821638bbc6 100644

> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

> @@ -778,7 +778,6 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)

>   	struct hmm_range *range;

>   	unsigned long i;

>   	uint64_t *pfns;

> -	int retry = 0;

>   	int r = 0;

>   

>   	if (!mm) /* Happens during process shutdown */

> @@ -822,7 +821,6 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)

>   	hmm_range_register(range, mirror, start,

>   			   start + ttm->num_pages * PAGE_SIZE, PAGE_SHIFT);

>   

> -retry:

>   	/*

>   	 * Just wait for range to be valid, safe to ignore return value as we

>   	 * will use the return value of hmm_range_fault() below under the

> @@ -831,24 +829,12 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)

>   	hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT);

>   

>   	down_read(&mm->mmap_sem);

> -

>   	r = hmm_range_fault(range, 0);

> -	if (unlikely(r < 0)) {

> -		if (likely(r == -EAGAIN)) {

> -			/*

> -			 * return -EAGAIN, mmap_sem is dropped

> -			 */

> -			if (retry++ < MAX_RETRY_HMM_RANGE_FAULT)

> -				goto retry;

> -			else

> -				pr_err("Retry hmm fault too many times\n");

> -		}

> -

> -		goto out_up_read;

> -	}

> -

>   	up_read(&mm->mmap_sem);

>   

> +	if (unlikely(r < 0))

> +		goto out_free_pfns;

> +

>   	for (i = 0; i < ttm->num_pages; i++) {

>   		pages[i] = hmm_device_entry_to_page(range, pfns[i]);

>   		if (unlikely(!pages[i])) {

> @@ -864,9 +850,6 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)

>   

>   	return 0;

>   

> -out_up_read:

> -	if (likely(r != -EAGAIN))

> -		up_read(&mm->mmap_sem);

>   out_free_pfns:

>   	hmm_range_unregister(range);

>   	kvfree(pfns);