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mm: use single SWP_DEVICE_EXCLUSIVE entry type

Browse source 
There is no need for the distinction anymore; let's merge the readable and
writable device-exclusive entries into a single device-exclusive entry
type.

Link: https://lkml.kernel.org/r/20250210193801.781278-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alistair Popple <apopple@nvidia.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lyude <lyude@redhat.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yanteng Si <si.yanteng@linux.dev>
Cc: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2025-02-10 20:37:48 +01:00 • committed by Andrew Morton
parent 9a91459214
commit c25465eb76
5 changed files with 10 additions and 39 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
include/linux/swap.h
View file

@ -74,14 +74,13 @@ static inline int current_is_kswapd(void)
* to a special SWP_DEVICE_{READ|WRITE} entry.
*
* When a page is mapped by the device for exclusive access we set the CPU page
* table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
* table entries to a special SWP_DEVICE_EXCLUSIVE entry.
*/
#ifdef CONFIG_DEVICE_PRIVATE
#define SWP_DEVICE_NUM 4
#define SWP_DEVICE_NUM 3
#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
#define SWP_DEVICE_EXCLUSIVE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
#else
#define SWP_DEVICE_NUM 0
#endif

27
include/linux/swapops.h
View file

@ -186,26 +186,16 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry)
return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
}
static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
}
static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
{
return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
return swp_entry(SWP_DEVICE_EXCLUSIVE, offset);
}
static inline bool is_device_exclusive_entry(swp_entry_t entry)
{
return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
return swp_type(entry) == SWP_DEVICE_EXCLUSIVE;
}
static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
{
return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
}
#else /* CONFIG_DEVICE_PRIVATE */
static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
{
@ -227,12 +217,7 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry)
return false;
}
static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
{
return swp_entry(0, 0);
}
static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
return swp_entry(0, 0);
}
@ -242,10 +227,6 @@ static inline bool is_device_exclusive_entry(swp_entry_t entry)
return false;
}
static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
{
return false;
}
#endif /* CONFIG_DEVICE_PRIVATE */
#ifdef CONFIG_MIGRATION

8
mm/mprotect.c
View file

@ -225,14 +225,6 @@ static long change_pte_range(struct mmu_gather *tlb,
newpte = swp_entry_to_pte(entry);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_writable_device_exclusive_entry(entry)) {
entry = make_readable_device_exclusive_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_soft_dirty(oldpte))
newpte = pte_swp_mksoft_dirty(newpte);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_pte_marker_entry(entry)) {
/*
* Ignore error swap entries unconditionally,

5
mm/page_table_check.c
View file

@ -196,9 +196,8 @@ EXPORT_SYMBOL(__page_table_check_pud_clear);
/* Whether the swap entry cached writable information */
static inline bool swap_cached_writable(swp_entry_t entry)
{
return is_writable_device_exclusive_entry(entry) ||
is_writable_device_private_entry(entry) ||
is_writable_migration_entry(entry);
return is_writable_device_private_entry(entry) ||
is_writable_migration_entry(entry);
}
static inline void page_table_check_pte_flags(pte_t pte)

2
mm/rmap.c
View file

@ -2492,7 +2492,7 @@ struct page *make_device_exclusive(struct mm_struct *mm, unsigned long addr,
* do_swap_page() will trigger the conversion back while holding the
* folio lock.
*/
entry = make_writable_device_exclusive_entry(page_to_pfn(page));
entry = make_device_exclusive_entry(page_to_pfn(page));
swp_pte = swp_entry_to_pte(entry);
if (pte_soft_dirty(fw.pte))
swp_pte = pte_swp_mksoft_dirty(swp_pte);