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From: Dmitry Safonov <dima@arista.com>
To: linux-kernel@vger.kernel.org
Cc: Dmitry Safonov <0x7f454c46@gmail.com>,
	Dmitry Safonov <dima@arista.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Brian Geffon <bgeffon@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@redhat.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Minchan Kim <minchan@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>,
	linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: [PATCH 4/6] vm_ops: Rename .split() callback to .may_split()
Date: Tue, 13 Oct 2020 02:34:14 +0100	[thread overview]
Message-ID: <20201013013416.390574-5-dima@arista.com> (raw)
In-Reply-To: <20201013013416.390574-1-dima@arista.com>

Rename the callback to reflect that it's not called *on* or *after*
split, but rather some time before the splitting to check if it's
possible.

Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 drivers/dax/device.c | 4 ++--
 include/linux/mm.h   | 3 ++-
 ipc/shm.c            | 8 ++++----
 mm/hugetlb.c         | 2 +-
 mm/mmap.c            | 4 ++--
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 1e89513f3c59..223dd1d13d5c 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -276,7 +276,7 @@ static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
 	return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
 }
 
-static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
+static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
 {
 	struct file *filp = vma->vm_file;
 	struct dev_dax *dev_dax = filp->private_data;
@@ -299,7 +299,7 @@ static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
 static const struct vm_operations_struct dax_vm_ops = {
 	.fault = dev_dax_fault,
 	.huge_fault = dev_dax_huge_fault,
-	.split = dev_dax_split,
+	.may_split = dev_dax_may_split,
 	.pagesize = dev_dax_pagesize,
 };
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fd51a4a1f722..90887661ef44 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -549,7 +549,8 @@ enum page_entry_size {
 struct vm_operations_struct {
 	void (*open)(struct vm_area_struct * area);
 	void (*close)(struct vm_area_struct * area);
-	int (*split)(struct vm_area_struct * area, unsigned long addr);
+	/* Called any time before splitting to check if it's allowed */
+	int (*may_split)(struct vm_area_struct *area, unsigned long addr);
 	int (*mremap)(struct vm_area_struct *area, unsigned long flags);
 	vm_fault_t (*fault)(struct vm_fault *vmf);
 	vm_fault_t (*huge_fault)(struct vm_fault *vmf,
diff --git a/ipc/shm.c b/ipc/shm.c
index e25c7c6106bc..febd88daba8c 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -434,13 +434,13 @@ static vm_fault_t shm_fault(struct vm_fault *vmf)
 	return sfd->vm_ops->fault(vmf);
 }
 
-static int shm_split(struct vm_area_struct *vma, unsigned long addr)
+static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
 {
 	struct file *file = vma->vm_file;
 	struct shm_file_data *sfd = shm_file_data(file);
 
-	if (sfd->vm_ops->split)
-		return sfd->vm_ops->split(vma, addr);
+	if (sfd->vm_ops->may_split)
+		return sfd->vm_ops->may_split(vma, addr);
 
 	return 0;
 }
@@ -582,7 +582,7 @@ static const struct vm_operations_struct shm_vm_ops = {
 	.open	= shm_open,	/* callback for a new vm-area open */
 	.close	= shm_close,	/* callback for when the vm-area is released */
 	.fault	= shm_fault,
-	.split	= shm_split,
+	.may_split = shm_may_split,
 	.pagesize = shm_pagesize,
 #if defined(CONFIG_NUMA)
 	.set_policy = shm_set_policy,
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 67fc6383995b..c4dc0e453be1 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3759,7 +3759,7 @@ const struct vm_operations_struct hugetlb_vm_ops = {
 	.fault = hugetlb_vm_op_fault,
 	.open = hugetlb_vm_op_open,
 	.close = hugetlb_vm_op_close,
-	.split = hugetlb_vm_op_split,
+	.may_split = hugetlb_vm_op_split,
 	.pagesize = hugetlb_vm_op_pagesize,
 };
 
diff --git a/mm/mmap.c b/mm/mmap.c
index 50f853b0ec39..a62cb3ccafce 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2693,8 +2693,8 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	struct vm_area_struct *new;
 	int err;
 
-	if (vma->vm_ops && vma->vm_ops->split) {
-		err = vma->vm_ops->split(vma, addr);
+	if (vma->vm_ops && vma->vm_ops->may_split) {
+		err = vma->vm_ops->may_split(vma, addr);
 		if (err)
 			return err;
 	}
-- 
2.28.0



  parent reply	other threads:[~2020-10-13  1:34 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-13  1:34 [PATCH 0/6] mremap: move_vma() fixes Dmitry Safonov
2020-10-13  1:34 ` [PATCH 1/6] mm/mremap: Account memory on do_munmap() failure Dmitry Safonov
2020-10-13  1:34 ` [PATCH 2/6] mm/mremap: For MREMAP_DONTUNMAP check security_vm_enough_memory_mm() Dmitry Safonov
2020-12-28 18:21   ` Brian Geffon
2020-12-28 19:12     ` Dmitry Safonov
2020-12-30 15:43       ` Brian Geffon
2020-10-13  1:34 ` [PATCH 3/6] mremap: Don't allow MREMAP_DONTUNMAP on special_mappings and aio Dmitry Safonov
2020-12-28 18:03   ` Brian Geffon
2020-12-28 19:33     ` Dmitry Safonov
2020-12-28 19:43       ` Dmitry Safonov
2020-10-13  1:34 ` Dmitry Safonov [this message]
2020-10-13  1:34 ` [PATCH 5/6] mremap: Check if it's possible to split original vma Dmitry Safonov
2020-10-13  1:34 ` [PATCH 6/6] mm: Forbid splitting special mappings Dmitry Safonov
2021-01-22 12:58   ` Will Deacon
2021-01-22 13:00     ` Will Deacon
2021-01-22 19:52       ` Dmitry Safonov

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