linux-kernel - [PATCH 4/6] vm_ops: Rename .split() callback to .may

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Message-Id: <20201013013416.390574-5-dima@arista.com>
Date:   Tue, 13 Oct 2020 02:34:14 +0100
From:   Dmitry Safonov <dima@...sta.com>
To:     linux-kernel@...r.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@...il.com>,
        Dmitry Safonov <dima@...sta.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Brian Geffon <bgeffon@...gle.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Hugh Dickins <hughd@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Minchan Kim <minchan@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Will Deacon <will@...nel.org>, linux-aio@...ck.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 4/6] vm_ops: Rename .split() callback to .may_split()

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@...sta.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