linux-kernel - [PATCH v1 11/14] mm/mshare: unmap vmas in mshare

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Message-Id: <fa5583368b0a6492ecb13180c29d7bfb29f73dd9.1649370874.git.khalid.aziz@oracle.com>
Date:   Mon, 11 Apr 2022 10:05:55 -0600
From:   Khalid Aziz <khalid.aziz@...cle.com>
To:     akpm@...ux-foundation.org, willy@...radead.org
Cc:     Khalid Aziz <khalid.aziz@...cle.com>, aneesh.kumar@...ux.ibm.com,
        arnd@...db.de, 21cnbao@...il.com, corbet@....net,
        dave.hansen@...ux.intel.com, david@...hat.com,
        ebiederm@...ssion.com, hagen@...u.net, jack@...e.cz,
        keescook@...omium.org, kirill@...temov.name, kucharsk@...il.com,
        linkinjeon@...nel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        longpeng2@...wei.com, luto@...nel.org, markhemm@...glemail.com,
        pcc@...gle.com, rppt@...nel.org, sieberf@...zon.com,
        sjpark@...zon.de, surenb@...gle.com, tst@...oebel-theuer.de,
        yzaikin@...gle.com
Subject: [PATCH v1 11/14] mm/mshare: unmap vmas in mshare_unlink

mshare() maps in vma for the calling task. These vmas should be
unmapped when the task calls mshare_unlink(). Add minimal code to
unmap vmas.

Signed-off-by: Khalid Aziz <khalid.aziz@...cle.com>
---
 mm/mshare.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/mm/mshare.c b/mm/mshare.c
index 40c495ffc0ca..ec23d1db79b2 100644
--- a/mm/mshare.c
+++ b/mm/mshare.c
@@ -490,6 +490,17 @@ SYSCALL_DEFINE1(mshare_unlink, const char *, name)
 		mmput(info->mm);
 		kfree(info);
 	} else {
+		/*
+		 * TODO: If mshare'd range is still mapped in the process,
+		 * it should be unmapped. Following is minimal code and
+		 * might need fix up
+		 */
+		unsigned long tmp;
+
+		tmp = info->mm->task_size - info->mm->mmap_base;
+		if (info->host_mm != current->mm)
+			vm_munmap(info->mm->mmap_base, tmp);
+
 		dput(dentry);
 	}
 
-- 
2.32.0