[PATCH v2 3/7] mm/hmm: replace the block argument to hmm_range_fault with a flags value
Ralph Campbell
rcampbell at nvidia.com
Fri Jul 26 00:56:46 UTC 2019
From: Christoph Hellwig <hch at lst.de>
This allows easier expansion to other flags, and also makes the
callers a little easier to read.
Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Ralph Campbell <rcampbell at nvidia.com>
Cc: "Jérôme Glisse" <jglisse at redhat.com>
Cc: Jason Gunthorpe <jgg at mellanox.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_svm.c | 2 +-
include/linux/hmm.h | 11 +++-
mm/hmm.c | 74 ++++++++++++-------------
4 files changed, 48 insertions(+), 41 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index e51b48ac48eb..12a59ac83f72 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -832,7 +832,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
down_read(&mm->mmap_sem);
- r = hmm_range_fault(range, true);
+ r = hmm_range_fault(range, 0);
if (unlikely(r < 0)) {
if (likely(r == -EAGAIN)) {
/*
diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 79b29c918717..49b520c60fc5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -505,7 +505,7 @@ nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range)
return -EBUSY;
}
- ret = hmm_range_fault(range, true);
+ ret = hmm_range_fault(range, 0);
if (ret <= 0) {
if (ret == 0)
ret = -EBUSY;
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 659e25a15700..15f1b113be3c 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -406,12 +406,19 @@ int hmm_range_register(struct hmm_range *range,
unsigned long end,
unsigned page_shift);
void hmm_range_unregister(struct hmm_range *range);
+
+/*
+ * Retry fault if non-blocking, drop mmap_sem and return -EAGAIN in that case.
+ */
+#define HMM_FAULT_ALLOW_RETRY (1 << 0)
+
long hmm_range_snapshot(struct hmm_range *range);
-long hmm_range_fault(struct hmm_range *range, bool block);
+long hmm_range_fault(struct hmm_range *range, unsigned int flags);
+
long hmm_range_dma_map(struct hmm_range *range,
struct device *device,
dma_addr_t *daddrs,
- bool block);
+ unsigned int flags);
long hmm_range_dma_unmap(struct hmm_range *range,
struct vm_area_struct *vma,
struct device *device,
diff --git a/mm/hmm.c b/mm/hmm.c
index 362944b0fbca..84f2791d3510 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -281,7 +281,7 @@ struct hmm_vma_walk {
struct dev_pagemap *pgmap;
unsigned long last;
bool fault;
- bool block;
+ unsigned int flags;
};
static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
@@ -293,8 +293,11 @@ static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
struct vm_area_struct *vma = walk->vma;
vm_fault_t ret;
- flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY;
- flags |= write_fault ? FAULT_FLAG_WRITE : 0;
+ if (hmm_vma_walk->flags & HMM_FAULT_ALLOW_RETRY)
+ flags |= FAULT_FLAG_ALLOW_RETRY;
+ if (write_fault)
+ flags |= FAULT_FLAG_WRITE;
+
ret = handle_mm_fault(vma, addr, flags);
if (ret & VM_FAULT_RETRY) {
/* Note, handle_mm_fault did up_read(&mm->mmap_sem)) */
@@ -1012,26 +1015,26 @@ long hmm_range_snapshot(struct hmm_range *range)
}
EXPORT_SYMBOL(hmm_range_snapshot);
-/*
- * hmm_range_fault() - try to fault some address in a virtual address range
- * @range: range being faulted
- * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
- * Return: number of valid pages in range->pfns[] (from range start
- * address). This may be zero. If the return value is negative,
- * then one of the following values may be returned:
+/**
+ * hmm_range_fault - try to fault some address in a virtual address range
+ * @range: range being faulted
+ * @flags: HMM_FAULT_* flags
*
- * -EINVAL invalid arguments or mm or virtual address are in an
- * invalid vma (for instance device file vma).
- * -ENOMEM: Out of memory.
- * -EPERM: Invalid permission (for instance asking for write and
- * range is read only).
- * -EAGAIN: If you need to retry and mmap_sem was drop. This can only
- * happens if block argument is false.
- * -EBUSY: If the the range is being invalidated and you should wait
- * for invalidation to finish.
- * -EFAULT: Invalid (ie either no valid vma or it is illegal to access
- * that range), number of valid pages in range->pfns[] (from
- * range start address).
+ * Return: the number of valid pages in range->pfns[] (from range start
+ * address), which may be zero. On error one of the following status codes
+ * can be returned:
+ *
+ * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma
+ * (e.g., device file vma).
+ * -ENOMEM: Out of memory.
+ * -EPERM: Invalid permission (e.g., asking for write and range is read
+ * only).
+ * -EAGAIN: A page fault needs to be retried and mmap_sem was dropped.
+ * -EBUSY: The range has been invalidated and the caller needs to wait for
+ * the invalidation to finish.
+ * -EFAULT: Invalid (i.e., either no valid vma or it is illegal to access
+ * that range) number of valid pages in range->pfns[] (from
+ * range start address).
*
* This is similar to a regular CPU page fault except that it will not trigger
* any memory migration if the memory being faulted is not accessible by CPUs
@@ -1040,7 +1043,7 @@ EXPORT_SYMBOL(hmm_range_snapshot);
* On error, for one virtual address in the range, the function will mark the
* corresponding HMM pfn entry with an error flag.
*/
-long hmm_range_fault(struct hmm_range *range, bool block)
+long hmm_range_fault(struct hmm_range *range, unsigned int flags)
{
const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP;
unsigned long start = range->start, end;
@@ -1086,7 +1089,7 @@ long hmm_range_fault(struct hmm_range *range, bool block)
hmm_vma_walk.pgmap = NULL;
hmm_vma_walk.last = start;
hmm_vma_walk.fault = true;
- hmm_vma_walk.block = block;
+ hmm_vma_walk.flags = flags;
hmm_vma_walk.range = range;
mm_walk.private = &hmm_vma_walk;
end = min(range->end, vma->vm_end);
@@ -1125,25 +1128,22 @@ long hmm_range_fault(struct hmm_range *range, bool block)
EXPORT_SYMBOL(hmm_range_fault);
/**
- * hmm_range_dma_map() - hmm_range_fault() and dma map page all in one.
- * @range: range being faulted
- * @device: device against to dma map page to
- * @daddrs: dma address of mapped pages
- * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
- * Return: number of pages mapped on success, -EAGAIN if mmap_sem have been
- * drop and you need to try again, some other error value otherwise
+ * hmm_range_dma_map - hmm_range_fault() and dma map page all in one.
+ * @range: range being faulted
+ * @device: device to map page to
+ * @daddrs: array of dma addresses for the mapped pages
+ * @flags: HMM_FAULT_*
*
- * Note same usage pattern as hmm_range_fault().
+ * Return: the number of pages mapped on success (including zero), or any
+ * status return from hmm_range_fault() otherwise.
*/
-long hmm_range_dma_map(struct hmm_range *range,
- struct device *device,
- dma_addr_t *daddrs,
- bool block)
+long hmm_range_dma_map(struct hmm_range *range, struct device *device,
+ dma_addr_t *daddrs, unsigned int flags)
{
unsigned long i, npages, mapped;
long ret;
- ret = hmm_range_fault(range, block);
+ ret = hmm_range_fault(range, flags);
if (ret <= 0)
return ret ? ret : -EBUSY;
--
2.20.1
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