mm: prefer vma_[start,end]_pgoff() to vma->vm_pgoff in kernel/

Be consistent in using vma_start_pgoff() and vma_end_pgoff(), which clearly
indicates which part of the VMA the page offset refers to and aids
greppability.

This is part of a broader series laying the ground to provide a virtual
page offset for MAP_PRIVATE-file backed anon folios.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-19-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> # for kernel/dma
Reviewed-by: Gregory Price <gourry@gourry.net>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/dma/coherent.c

@@ -236,14 +236,15 @@ static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
 {
 	if (mem && vaddr >= mem->virt_base && vaddr + size <=
 		   (mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
-		unsigned long off = vma->vm_pgoff;
+		const pgoff_t pgoff_start = vma_start_pgoff(vma);
+		const pgoff_t pgoff_end = vma_end_pgoff(vma);
 		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 		unsigned long user_count = vma_pages(vma);
 		int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 
 		*ret = -ENXIO;
-		if (off < count && user_count <= count - off) {
-			unsigned long pfn = mem->pfn_base + start + off;
+		if (pgoff_start < count && pgoff_end <= count) {
+			unsigned long pfn = mem->pfn_base + start + pgoff_start;
 			*ret = remap_pfn_range(vma, vma->vm_start, pfn,
 					       user_count << PAGE_SHIFT,
 					       vma->vm_page_prot);

kernel/dma/direct.c

@@ -534,6 +534,8 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
 	unsigned long user_count = vma_pages(vma);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr));
+	const pgoff_t pgoff_start = vma_start_pgoff(vma);
+	const pgoff_t pgoff_end = vma_end_pgoff(vma);
 	int ret = -ENXIO;
 
 	vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
@@ -545,9 +547,9 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
 	if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret))
 		return ret;
 
-	if (vma->vm_pgoff >= count || user_count > count - vma->vm_pgoff)
+	if (pgoff_start >= count || pgoff_end > count)
 		return -ENXIO;
-	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
+	return remap_pfn_range(vma, vma->vm_start, pfn + pgoff_start,
 			user_count << PAGE_SHIFT, vma->vm_page_prot);
 }
 

kernel/dma/mapping.c

@@ -761,12 +761,14 @@ EXPORT_SYMBOL_GPL(dma_free_pages);
 int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
 		size_t size, struct page *page)
 {
-	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	const pgoff_t pgoff_start = vma_start_pgoff(vma);
+	const pgoff_t pgoff_end = vma_end_pgoff(vma);
+	const unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 
-	if (vma->vm_pgoff >= count || vma_pages(vma) > count - vma->vm_pgoff)
+	if (pgoff_start >= count || pgoff_end > count)
 		return -ENXIO;
 	return remap_pfn_range(vma, vma->vm_start,
-			       page_to_pfn(page) + vma->vm_pgoff,
+			       page_to_pfn(page) + pgoff_start,
 			       vma_pages(vma) << PAGE_SHIFT, vma->vm_page_prot);
 }
 EXPORT_SYMBOL_GPL(dma_mmap_pages);

kernel/dma/ops_helpers.c

@@ -39,7 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 #ifdef CONFIG_MMU
 	unsigned long user_count = vma_pages(vma);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	unsigned long off = vma->vm_pgoff;
+	unsigned long off = vma_start_pgoff(vma);
 	struct page *page = dma_common_vaddr_to_page(cpu_addr);
 	int ret = -ENXIO;
 
@@ -52,7 +52,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 		return -ENXIO;
 
 	return remap_pfn_range(vma, vma->vm_start,
-			page_to_pfn(page) + vma->vm_pgoff,
+			page_to_pfn(page) + vma_start_pgoff(vma),
 			user_count << PAGE_SHIFT, vma->vm_page_prot);
 #else
 	return -ENXIO;

kernel/events/core.c

@@ -6998,7 +6998,7 @@ static void perf_mmap_open(struct vm_area_struct *vma)
 	refcount_inc(&event->mmap_count);
 	refcount_inc(&event->rb->mmap_count);
 
-	if (vma->vm_pgoff)
+	if (vma_start_pgoff(vma))
 		refcount_inc(&event->rb->aux_mmap_count);
 
 	if (mapped)
@@ -7032,7 +7032,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
 	 * The AUX buffer is strictly a sub-buffer, serialize using aux_mutex
 	 * to avoid complications.
 	 */
-	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
+	if (rb_has_aux(rb) && vma_start_pgoff(vma) == rb->aux_pgoff &&
 	    refcount_dec_and_mutex_lock(&rb->aux_mmap_count, &rb->aux_mutex)) {
 		/*
 		 * Stop all AUX events that are writing to this buffer,
@@ -7192,7 +7192,8 @@ static int map_range(struct perf_buffer *rb, struct vm_area_struct *vma)
 	 */
 	for (pagenum = 0; pagenum < nr_pages; pagenum++) {
 		unsigned long va = vma->vm_start + PAGE_SIZE * pagenum;
-		struct page *page = perf_mmap_to_page(rb, vma->vm_pgoff + pagenum);
+		struct page *page = perf_mmap_to_page(rb,
+				vma_start_pgoff(vma) + pagenum);
 
 		if (page == NULL) {
 			err = -EINVAL;
@@ -7346,6 +7347,7 @@ static int perf_mmap_rb(struct vm_area_struct *vma, struct perf_event *event,
 static int perf_mmap_aux(struct vm_area_struct *vma, struct perf_event *event,
 			 unsigned long nr_pages)
 {
+	const pgoff_t pgoff_start = vma_start_pgoff(vma);
 	long extra = 0, user_extra = nr_pages;
 	u64 aux_offset, aux_size;
 	struct perf_buffer *rb;
@@ -7368,11 +7370,11 @@ static int perf_mmap_aux(struct vm_area_struct *vma, struct perf_event *event,
 	if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
 		return -EINVAL;
 
-	if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
+	if (aux_offset != pgoff_start << PAGE_SHIFT)
 		return -EINVAL;
 
 	/* already mapped with a different offset */
-	if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
+	if (rb_has_aux(rb) && rb->aux_pgoff != pgoff_start)
 		return -EINVAL;
 
 	if (aux_size != nr_pages * PAGE_SIZE)
@@ -7402,7 +7404,7 @@ static int perf_mmap_aux(struct vm_area_struct *vma, struct perf_event *event,
 		if (vma->vm_flags & VM_WRITE)
 			rb_flags |= RING_BUFFER_WRITABLE;
 
-		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
+		ret = rb_alloc_aux(rb, event, pgoff_start, nr_pages,
 				   event->attr.aux_watermark, rb_flags);
 		if (ret) {
 			refcount_dec(&rb->mmap_count);
@@ -7459,7 +7461,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 		if (event->state <= PERF_EVENT_STATE_REVOKED)
 			return -ENODEV;
 
-		if (vma->vm_pgoff == 0)
+		if (!vma_start_pgoff(vma))
 			ret = perf_mmap_rb(vma, event, nr_pages);
 		else
 			ret = perf_mmap_aux(vma, event, nr_pages);
@@ -9886,7 +9888,7 @@ static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
 					struct perf_addr_filter_range *fr)
 {
 	unsigned long vma_size = vma->vm_end - vma->vm_start;
-	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
+	unsigned long off = vma_start_pgoff(vma) << PAGE_SHIFT;
 	struct file *file = vma->vm_file;
 
 	if (!perf_addr_filter_match(filter, file, off, vma_size))
@@ -9976,7 +9978,7 @@ void perf_event_mmap(struct vm_area_struct *vma)
 			/* .tid */
 			.start  = vma->vm_start,
 			.len    = vma->vm_end - vma->vm_start,
-			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
+			.pgoff  = (u64)vma_start_pgoff(vma) << PAGE_SHIFT,
 		},
 		/* .maj (attr_mmap2 only) */
 		/* .min (attr_mmap2 only) */

kernel/events/uprobes.c

@@ -144,12 +144,14 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
 
 static unsigned long offset_to_vaddr(struct vm_area_struct *vma, loff_t offset)
 {
-	return vma->vm_start + offset - ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+	return vma->vm_start + offset -
+		((loff_t)vma_start_pgoff(vma) << PAGE_SHIFT);
 }
 
 static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
 {
-	return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start);
+	return ((loff_t)vma_start_pgoff(vma) << PAGE_SHIFT) +
+		(vaddr - vma->vm_start);
 }
 
 /**
@@ -1482,7 +1484,7 @@ static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
 		    file_inode(vma->vm_file) != uprobe->inode)
 			continue;
 
-		offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+		offset = (loff_t)vma_start_pgoff(vma) << PAGE_SHIFT;
 		if (uprobe->offset <  offset ||
 		    uprobe->offset >= offset + vma->vm_end - vma->vm_start)
 			continue;
@@ -2453,7 +2455,8 @@ static struct uprobe *find_active_uprobe_speculative(unsigned long bp_vaddr)
 	if (!vm_file)
 		return NULL;
 
-	offset = (loff_t)(vma->vm_pgoff << PAGE_SHIFT) + (bp_vaddr - vma->vm_start);
+	offset = (loff_t)(vma_start_pgoff(vma) << PAGE_SHIFT) +
+		(bp_vaddr - vma->vm_start);
 	uprobe = find_uprobe_rcu(vm_file->f_inode, offset);
 	if (!uprobe)
 		return NULL;

kernel/kcov.c

@@ -512,7 +512,7 @@ static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
 
 	spin_lock_irqsave(&kcov->lock, flags);
 	size = kcov->size * sizeof(unsigned long);
-	if (kcov->area == NULL || vma->vm_pgoff != 0 ||
+	if (kcov->area == NULL || vma_start_pgoff(vma) ||
 	    vma->vm_end - vma->vm_start != size) {
 		res = -EINVAL;
 		goto exit;

kernel/trace/ring_buffer.c

@@ -7611,7 +7611,8 @@ static int __rb_inc_dec_mapped(struct ring_buffer_per_cpu *cpu_buffer,
 static int __rb_map_vma(struct ring_buffer_per_cpu *cpu_buffer,
 			struct vm_area_struct *vma)
 {
-	unsigned long nr_subbufs, nr_pages, nr_vma_pages, pgoff = vma->vm_pgoff;
+	unsigned long nr_subbufs, nr_pages, nr_vma_pages;
+	pgoff_t pgoff = vma_start_pgoff(vma);
 	unsigned int subbuf_pages, subbuf_order;
 	struct page **pages __free(kfree) = NULL;
 	int p = 0, s = 0;