Commit 0ca22723 authored by Vishal Moola (Oracle)'s avatar Vishal Moola (Oracle) Committed by Andrew Morton
Browse files

hugetlb: move vm_fault declaration to the top of hugetlb_fault() 

hugetlb_fault() currently defines a vm_fault to pass to the generic
handle_userfault() function.  We can move this definition to the top of
hugetlb_fault() so that it can be used throughout the rest of the hugetlb
fault path.

This will help cleanup a number of excess variables and function arguments
throughout the stack.  Also, since vm_fault already has space to store the
page offset, use that instead and get rid of idx.

Link: https://lkml.kernel.org/r/20240221234732.187629-3-vishal.moola@gmail.com


Signed-off-by: default avatarVishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 997f0ecb

mm/hugetlb.c

+19 −13
Original line number Diff line number Diff line
@@ -6378,13 +6378,25 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	spinlock_t *ptl;

	vm_fault_t ret;

	u32 hash;

	pgoff_t idx;

	struct folio *folio = NULL;

	struct folio *pagecache_folio = NULL;

	struct hstate *h = hstate_vma(vma);

	struct address_space *mapping;

	int need_wait_lock = 0;

	unsigned long haddr = address & huge_page_mask(h);

	struct vm_fault vmf = {

		.vma = vma,

		.address = haddr,

		.real_address = address,

		.flags = flags,

		.pgoff = vma_hugecache_offset(h, vma, haddr),

		/* TODO: Track hugetlb faults using vm_fault */



		/*

		 * Some fields may not be initialized, be careful as it may

		 * be hard to debug if called functions make assumptions

		 */

	};



	/* TODO: Handle faults under the VMA lock */

	if (flags & FAULT_FLAG_VMA_LOCK) {
@@ -6398,8 +6410,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	 * the same page in the page cache.

	 */

	mapping = vma->vm_file->f_mapping;

	idx = vma_hugecache_offset(h, vma, haddr);

	hash = hugetlb_fault_mutex_hash(mapping, idx);

	hash = hugetlb_fault_mutex_hash(mapping, vmf.pgoff);

	mutex_lock(&hugetlb_fault_mutex_table[hash]);



	/*
@@ -6433,8 +6444,9 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
		 * hugetlb_no_page will drop vma lock and hugetlb fault

		 * mutex internally, which make us return immediately.

		 */

		return hugetlb_no_page(mm, vma, mapping, idx, address, ptep,

				      entry, flags);



		return hugetlb_no_page(mm, vma, mapping, vmf.pgoff, address,

					ptep, entry, flags);

	}



	ret = 0;
@@ -6480,7 +6492,8 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
		/* Just decrements count, does not deallocate */

		vma_end_reservation(h, vma, haddr);



		pagecache_folio = filemap_lock_hugetlb_folio(h, mapping, idx);

		pagecache_folio = filemap_lock_hugetlb_folio(h, mapping,

							     vmf.pgoff);

		if (IS_ERR(pagecache_folio))

			pagecache_folio = NULL;

	}
@@ -6495,13 +6508,6 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) &&

	    (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {

		if (!userfaultfd_wp_async(vma)) {

			struct vm_fault vmf = {

				.vma = vma,

				.address = haddr,

				.real_address = address,

				.flags = flags,

			};



			spin_unlock(ptl);

			if (pagecache_folio) {

				folio_unlock(pagecache_folio);