linux-kernel - [PATCH 16/23] s390: gmap use pte_unmap_unlock() not spin

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Message-ID: <5579873-d7b-65e-5de0-a2ba8a144e7@google.com>
Date:   Tue, 9 May 2023 22:02:32 -0700 (PDT)
From:   Hugh Dickins <hughd@...gle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
cc:     Mike Kravetz <mike.kravetz@...cle.com>,
        Mike Rapoport <rppt@...nel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        David Hildenbrand <david@...hat.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Qi Zheng <zhengqi.arch@...edance.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Michal Simek <monstr@...str.eu>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Helge Deller <deller@....de>,
        John David Anglin <dave.anglin@...l.net>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Alexandre Ghiti <alexghiti@...osinc.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
        "David S. Miller" <davem@...emloft.net>,
        Chris Zankel <chris@...kel.net>,
        Max Filippov <jcmvbkbc@...il.com>, x86@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        linux-m68k@...ts.linux-m68k.org, linux-mips@...r.kernel.org,
        linux-parisc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
        linux-sh@...r.kernel.org, sparclinux@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 16/23] s390: gmap use pte_unmap_unlock() not spin_unlock()

pte_alloc_map_lock() expects to be followed by pte_unmap_unlock(): to
keep balance in future, pass ptep as well as ptl to gmap_pte_op_end(),
and use pte_unmap_unlock() instead of direct spin_unlock() (even though
ptep ends up unused inside the macro).

Signed-off-by: Hugh Dickins <hughd@...gle.com>
---
 arch/s390/mm/gmap.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index d198fc9475a2..638dcd9bc820 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -895,12 +895,12 @@ static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
 
 /**
  * gmap_pte_op_end - release the page table lock
- * @ptl: pointer to the spinlock pointer
+ * @ptep: pointer to the locked pte
+ * @ptl: pointer to the page table spinlock
  */
-static void gmap_pte_op_end(spinlock_t *ptl)
+static void gmap_pte_op_end(pte_t *ptep, spinlock_t *ptl)
 {
-	if (ptl)
-		spin_unlock(ptl);
+	pte_unmap_unlock(ptep, ptl);
 }
 
 /**
@@ -1011,7 +1011,7 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
 {
 	int rc;
 	pte_t *ptep;
-	spinlock_t *ptl = NULL;
+	spinlock_t *ptl;
 	unsigned long pbits = 0;
 
 	if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
@@ -1025,7 +1025,7 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
 	pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
 	/* Protect and unlock. */
 	rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
-	gmap_pte_op_end(ptl);
+	gmap_pte_op_end(ptep, ptl);
 	return rc;
 }
 
@@ -1154,7 +1154,7 @@ int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
 				/* Do *NOT* clear the _PAGE_INVALID bit! */
 				rc = 0;
 			}
-			gmap_pte_op_end(ptl);
+			gmap_pte_op_end(ptep, ptl);
 		}
 		if (!rc)
 			break;
@@ -1248,7 +1248,7 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
 			if (!rc)
 				gmap_insert_rmap(sg, vmaddr, rmap);
 			spin_unlock(&sg->guest_table_lock);
-			gmap_pte_op_end(ptl);
+			gmap_pte_op_end(ptep, ptl);
 		}
 		radix_tree_preload_end();
 		if (rc) {
@@ -2156,7 +2156,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
 			tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
 			if (!tptep) {
 				spin_unlock(&sg->guest_table_lock);
-				gmap_pte_op_end(ptl);
+				gmap_pte_op_end(sptep, ptl);
 				radix_tree_preload_end();
 				break;
 			}
@@ -2167,7 +2167,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
 				rmap = NULL;
 				rc = 0;
 			}
-			gmap_pte_op_end(ptl);
+			gmap_pte_op_end(sptep, ptl);
 			spin_unlock(&sg->guest_table_lock);
 		}
 		radix_tree_preload_end();
@@ -2495,7 +2495,7 @@ void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
 				continue;
 			if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
 				set_bit(i, bitmap);
-			spin_unlock(ptl);
+			pte_unmap_unlock(ptep, ptl);
 		}
 	}
 	gmap_pmd_op_end(gmap, pmdp);
-- 
2.35.3