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iommufd/iova_bitmap: Remove iterator logic

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The newly introduced dynamic pinning/windowing greatly simplifies the code
and there's no obvious performance advantage that has been identified that
justifies maintinaing both schemes.

Remove the iterator logic and have iova_bitmap_for_each() just invoke the
callback with the total iova/length.

Fixes: 2780025e01 ("iommufd/iova_bitmap: Handle recording beyond the mapped pages")
Link: https://lore.kernel.org/r/20240627110105.62325-12-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Matt Ochs <mochs@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Joao Martins 2024-06-27 12:01:05 +01:00 committed by Jason Gunthorpe
parent 7a7bba1624
commit 53e6b65693
1 changed files with 2 additions and 95 deletions
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97
drivers/iommu/iommufd/iova_bitmap.c
View file

@ -116,12 +116,6 @@ struct iova_bitmap {
/* length of the IOVA range for the whole bitmap */
size_t length;
/* length of the IOVA range set ahead the pinned pages */
unsigned long set_ahead_length;
/* true if it using the iterator otherwise it pins dynamically */
bool iterator;
};
/*
@ -354,40 +348,6 @@ static bool iova_bitmap_mapped_range(struct iova_bitmap_map *mapped,
(iova + length - 1) <= (mapped->iova + mapped->length - 1));
}
/*
* Returns true if there's not more data to iterate.
*/
static bool iova_bitmap_done(struct iova_bitmap *bitmap)
{
return bitmap->mapped_base_index >= bitmap->mapped_total_index;
}
static int iova_bitmap_set_ahead(struct iova_bitmap *bitmap,
size_t set_ahead_length)
{
int ret = 0;
while (set_ahead_length > 0 && !iova_bitmap_done(bitmap)) {
unsigned long length = iova_bitmap_mapped_length(bitmap);
unsigned long iova = iova_bitmap_mapped_iova(bitmap);
ret = iova_bitmap_get(bitmap);
if (ret)
break;
length = min(length, set_ahead_length);
iova_bitmap_set(bitmap, iova, length);
set_ahead_length -= length;
bitmap->mapped_base_index +=
iova_bitmap_offset_to_index(bitmap, length - 1) + 1;
iova_bitmap_put(bitmap);
}
bitmap->set_ahead_length = 0;
return ret;
}
/*
* Advances to a selected range, releases the current pinned
* pages and pins the next set of bitmap pages.
@ -409,36 +369,6 @@ static int iova_bitmap_advance_to(struct iova_bitmap *bitmap,
return iova_bitmap_get(bitmap);
}
/*
* Advances to the next range, releases the current pinned
* pages and pins the next set of bitmap pages.
* Returns 0 on success or otherwise errno.
*/
static int iova_bitmap_advance(struct iova_bitmap *bitmap)
{
unsigned long iova = iova_bitmap_mapped_length(bitmap) - 1;
unsigned long count = iova_bitmap_offset_to_index(bitmap, iova) + 1;
bitmap->mapped_base_index += count;
iova_bitmap_put(bitmap);
/* Iterate, set and skip any bits requested for next iteration */
if (bitmap->set_ahead_length) {
int ret;
ret = iova_bitmap_set_ahead(bitmap, bitmap->set_ahead_length);
if (ret)
return ret;
}
if (iova_bitmap_done(bitmap))
return 0;
/* When advancing the index we pin the next set of bitmap pages */
return iova_bitmap_get(bitmap);
}
/**
* iova_bitmap_for_each() - Iterates over the bitmap
* @bitmap: IOVA bitmap to iterate
@ -455,23 +385,7 @@ static int iova_bitmap_advance(struct iova_bitmap *bitmap)
int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,
iova_bitmap_fn_t fn)
{
int ret = 0;
ret = iova_bitmap_get(bitmap);
if (ret)
return ret;
bitmap->iterator = true;
for (; !iova_bitmap_done(bitmap) && !ret;
ret = iova_bitmap_advance(bitmap)) {
ret = fn(bitmap, iova_bitmap_mapped_iova(bitmap),
iova_bitmap_mapped_length(bitmap), opaque);
if (ret)
break;
}
bitmap->iterator = false;
return ret;
return fn(bitmap, bitmap->iova, bitmap->length, opaque);
}
EXPORT_SYMBOL_NS_GPL(iova_bitmap_for_each, IOMMUFD);
@ -492,15 +406,12 @@ void iova_bitmap_set(struct iova_bitmap *bitmap,
unsigned long cur_bit, last_bit, last_page_idx;
update_indexes:
if (unlikely(!bitmap->iterator &&
!iova_bitmap_mapped_range(mapped, iova, length))) {
if (unlikely(!iova_bitmap_mapped_range(mapped, iova, length))) {
/*
* The attempt to advance the base index to @iova
* may fail if it's out of bounds, or pinning the pages
* returns an error.
*
* It is a no-op if within a iova_bitmap_for_each() closure.
*/
if (iova_bitmap_advance_to(bitmap, iova))
return;
@ -523,10 +434,6 @@ void iova_bitmap_set(struct iova_bitmap *bitmap,
unsigned long left =
((last_bit - cur_bit + 1) << mapped->pgshift);
if (bitmap->iterator) {
bitmap->set_ahead_length = left;
return;
}
iova += (length - left);
length = left;
goto update_indexes;