mm: add vma_desc_size(), vma_desc_pages() helpers

It's useful to be able to determine the size of a VMA descriptor range
used on f_op->mmap_prepare, expressed both in bytes and pages, so add
helpers for both and update code that could make use of it to do so.

Link: https://lkml.kernel.org/r/5ac75e5ac627c06e62401dfda8c908eadac8dfec.1757534913.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index c1ece707b19511aad66fb3fd4695c29572c88736..86eb88f627149b651a8e10fa5e23e5be104545a9 100644 (file)
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -304,7 +304,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
 
        if (rw) {
                u64 to = min_t(loff_t, i_size_read(inode),
-                              from + desc->end - desc->start);
+                              from + vma_desc_size(desc));
 
                if (is_sparsed(ni)) {
                        /* Allocate clusters for rw map. */

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 892fe5dbf9de02bac4f4fddef7279442834996dc..0b97589aec6d2029d83bf5bf066e6407e2d32047 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3572,6 +3572,16 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
        return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 }
 
+static inline unsigned long vma_desc_size(struct vm_area_desc *desc)
+{
+       return desc->end - desc->start;
+}
+
+static inline unsigned long vma_desc_pages(struct vm_area_desc *desc)
+{
+       return vma_desc_size(desc) >> PAGE_SHIFT;
+}
+
 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
                                unsigned long vm_start, unsigned long vm_end)

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 60137305bc20fdab7d99a91eb6e5fcb413d0d9f6..62066ddb1e9c521271e5f7fdf266ad1c623c79aa 100644 (file)
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -120,7 +120,7 @@ static int secretmem_release(struct inode *inode, struct file *file)
 
 static int secretmem_mmap_prepare(struct vm_area_desc *desc)
 {
-       const unsigned long len = desc->end - desc->start;
+       const unsigned long len = vma_desc_size(desc);
 
        if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
                return -EINVAL;