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KVM: s390: Remove ptep_zap_softleaf_entry()

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Migration entries do not need to be removed.

The swap subsystem has been (and still is being) heavily reworked. The
current implementation of ptep_zap_softleaf_entry() has been slowly
modified and is now wrong, since it unconditionally calls
swap_put_entries_direct() for both swap and migration entries.

Remove ptep_zap_softleaf_entry() altogether, merge the path for proper
swap entries directly in the only caller, and ignore migration entries.

Fixes: 200197908d ("KVM: s390: Refactor and split some gmap helpers")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-11-imbrenda@linux.ibm.com>
This commit is contained in:
Claudio Imbrenda 2026-06-02 16:23:56 +02:00
parent 6ae67dcac7
commit c1edda54a0
1 changed files with 5 additions and 20 deletions
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25
arch/s390/mm/gmap_helpers.c
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@ -16,24 +16,6 @@
#include <linux/ksm.h>
#include <asm/gmap_helpers.h>
/**
* ptep_zap_softleaf_entry() - discard a software leaf entry.
* @mm: the mm
* @entry: the software leaf entry that needs to be zapped
*
* Discards the given software leaf entry. If the leaf entry was an actual
* swap entry (and not a migration entry, for example), the actual swapped
* page is also discarded from swap.
*/
static void ptep_zap_softleaf_entry(struct mm_struct *mm, softleaf_t entry)
{
if (softleaf_is_swap(entry))
dec_mm_counter(mm, MM_SWAPENTS);
else if (softleaf_is_migration(entry))
dec_mm_counter(mm, mm_counter(softleaf_to_folio(entry)));
swap_put_entries_direct(entry, 1);
}
/**
* try_get_locked_pte() - like get_locked_pte(), but atomic and with trylock
* @mm: the mm
@ -111,6 +93,7 @@ void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr)
{
struct vm_area_struct *vma;
spinlock_t *ptl; /* Lock for the host (userspace) page table */
softleaf_t sl;
pte_t *ptep;
mmap_assert_locked(mm);
@ -124,8 +107,10 @@ void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr)
ptep = try_get_locked_pte(mm, vmaddr, &ptl);
if (IS_ERR_OR_NULL(ptep))
return;
if (pte_swap(*ptep)) {
ptep_zap_softleaf_entry(mm, softleaf_from_pte(*ptep));
sl = softleaf_from_pte(*ptep);
if (pte_swap(*ptep) && softleaf_is_swap(sl)) {
dec_mm_counter(mm, MM_SWAPENTS);
swap_put_entries_direct(sl, 1);
pte_clear(mm, vmaddr, ptep);
}
pte_unmap_unlock(ptep, ptl);