diff options
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 510 |
1 files changed, 271 insertions, 239 deletions
@@ -5,6 +5,7 @@ #include <linux/spinlock.h> #include <linux/mm.h> +#include <linux/memfd.h> #include <linux/memremap.h> #include <linux/pagemap.h> #include <linux/rmap.h> @@ -17,6 +18,7 @@ #include <linux/hugetlb.h> #include <linux/migrate.h> #include <linux/mm_inline.h> +#include <linux/pagevec.h> #include <linux/sched/mm.h> #include <linux/shmem_fs.h> @@ -189,6 +191,19 @@ void unpin_user_page(struct page *page) EXPORT_SYMBOL(unpin_user_page); /** + * unpin_folio() - release a dma-pinned folio + * @folio: pointer to folio to be released + * + * Folios that were pinned via memfd_pin_folios() or other similar routines + * must be released either using unpin_folio() or unpin_folios(). + */ +void unpin_folio(struct folio *folio) +{ + gup_put_folio(folio, 1, FOLL_PIN); +} +EXPORT_SYMBOL_GPL(unpin_folio); + +/** * folio_add_pin - Try to get an additional pin on a pinned folio * @folio: The folio to be pinned * @@ -290,7 +305,7 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages, * 1) This code sees the page as already dirty, so it * skips the call to set_page_dirty(). That could happen * because clear_page_dirty_for_io() called - * page_mkclean(), followed by set_page_dirty(). + * folio_mkclean(), followed by set_page_dirty(). * However, now the page is going to get written back, * which meets the original intention of setting it * dirty, so all is well: clear_page_dirty_for_io() goes @@ -400,6 +415,40 @@ void unpin_user_pages(struct page **pages, unsigned long npages) } EXPORT_SYMBOL(unpin_user_pages); +/** + * unpin_folios() - release an array of gup-pinned folios. + * @folios: array of folios to be marked dirty and released. + * @nfolios: number of folios in the @folios array. + * + * For each folio in the @folios array, release the folio using gup_put_folio. + * + * Please see the unpin_folio() documentation for details. + */ +void unpin_folios(struct folio **folios, unsigned long nfolios) +{ + unsigned long i = 0, j; + + /* + * If this WARN_ON() fires, then the system *might* be leaking folios + * (by leaving them pinned), but probably not. More likely, gup/pup + * returned a hard -ERRNO error to the caller, who erroneously passed + * it here. + */ + if (WARN_ON(IS_ERR_VALUE(nfolios))) + return; + + while (i < nfolios) { + for (j = i + 1; j < nfolios; j++) + if (folios[i] != folios[j]) + break; + + if (folios[i]) + gup_put_folio(folios[i], j - i, FOLL_PIN); + i = j; + } +} +EXPORT_SYMBOL_GPL(unpin_folios); + /* * Set the MMF_HAS_PINNED if not set yet; after set it'll be there for the mm's * lifecycle. Avoid setting the bit unless necessary, or it might cause write @@ -413,7 +462,7 @@ static inline void mm_set_has_pinned_flag(unsigned long *mm_flags) #ifdef CONFIG_MMU -#if defined(CONFIG_ARCH_HAS_HUGEPD) || defined(CONFIG_HAVE_GUP_FAST) +#ifdef CONFIG_HAVE_GUP_FAST static int record_subpages(struct page *page, unsigned long sz, unsigned long addr, unsigned long end, struct page **pages) @@ -523,154 +572,7 @@ static struct folio *try_grab_folio_fast(struct page *page, int refs, return folio; } -#endif /* CONFIG_ARCH_HAS_HUGEPD || CONFIG_HAVE_GUP_FAST */ - -#ifdef CONFIG_ARCH_HAS_HUGEPD -static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, - unsigned long sz) -{ - unsigned long __boundary = (addr + sz) & ~(sz-1); - return (__boundary - 1 < end - 1) ? __boundary : end; -} - -/* - * Returns 1 if succeeded, 0 if failed, -EMLINK if unshare needed. - * - * NOTE: for the same entry, gup-fast and gup-slow can return different - * results (0 v.s. -EMLINK) depending on whether vma is available. This is - * the expected behavior, where we simply want gup-fast to fallback to - * gup-slow to take the vma reference first. - */ -static int gup_hugepte(struct vm_area_struct *vma, pte_t *ptep, unsigned long sz, - unsigned long addr, unsigned long end, unsigned int flags, - struct page **pages, int *nr, bool fast) -{ - unsigned long pte_end; - struct page *page; - struct folio *folio; - pte_t pte; - int refs; - - pte_end = (addr + sz) & ~(sz-1); - if (pte_end < end) - end = pte_end; - - pte = huge_ptep_get(ptep); - - if (!pte_access_permitted(pte, flags & FOLL_WRITE)) - return 0; - - /* hugepages are never "special" */ - VM_BUG_ON(!pfn_valid(pte_pfn(pte))); - - page = pte_page(pte); - refs = record_subpages(page, sz, addr, end, pages + *nr); - - if (fast) { - folio = try_grab_folio_fast(page, refs, flags); - if (!folio) - return 0; - } else { - folio = page_folio(page); - if (try_grab_folio(folio, refs, flags)) - return 0; - } - - if (unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) { - gup_put_folio(folio, refs, flags); - return 0; - } - - if (!pte_write(pte) && gup_must_unshare(vma, flags, &folio->page)) { - gup_put_folio(folio, refs, flags); - return -EMLINK; - } - - *nr += refs; - folio_set_referenced(folio); - return 1; -} - -/* - * NOTE: currently GUP for a hugepd is only possible on hugetlbfs file - * systems on Power, which does not have issue with folio writeback against - * GUP updates. When hugepd will be extended to support non-hugetlbfs or - * even anonymous memory, we need to do extra check as what we do with most - * of the other folios. See writable_file_mapping_allowed() and - * gup_fast_folio_allowed() for more information. - */ -static int gup_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, - unsigned long addr, unsigned int pdshift, - unsigned long end, unsigned int flags, - struct page **pages, int *nr, bool fast) -{ - pte_t *ptep; - unsigned long sz = 1UL << hugepd_shift(hugepd); - unsigned long next; - int ret; - - ptep = hugepte_offset(hugepd, addr, pdshift); - do { - next = hugepte_addr_end(addr, end, sz); - ret = gup_hugepte(vma, ptep, sz, addr, end, flags, pages, nr, - fast); - if (ret != 1) - return ret; - } while (ptep++, addr = next, addr != end); - - return 1; -} - -static struct page *follow_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, - unsigned long addr, unsigned int pdshift, - unsigned int flags, - struct follow_page_context *ctx) -{ - struct page *page; - struct hstate *h; - spinlock_t *ptl; - int nr = 0, ret; - pte_t *ptep; - - /* Only hugetlb supports hugepd */ - if (WARN_ON_ONCE(!is_vm_hugetlb_page(vma))) - return ERR_PTR(-EFAULT); - - h = hstate_vma(vma); - ptep = hugepte_offset(hugepd, addr, pdshift); - ptl = huge_pte_lock(h, vma->vm_mm, ptep); - ret = gup_hugepd(vma, hugepd, addr, pdshift, addr + PAGE_SIZE, - flags, &page, &nr, false); - spin_unlock(ptl); - - if (ret == 1) { - /* GUP succeeded */ - WARN_ON_ONCE(nr != 1); - ctx->page_mask = (1U << huge_page_order(h)) - 1; - return page; - } - - /* ret can be either 0 (translates to NULL) or negative */ - return ERR_PTR(ret); -} -#else /* CONFIG_ARCH_HAS_HUGEPD */ -static inline int gup_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, - unsigned long addr, unsigned int pdshift, - unsigned long end, unsigned int flags, - struct page **pages, int *nr, bool fast) -{ - return 0; -} - -static struct page *follow_hugepd(struct vm_area_struct *vma, hugepd_t hugepd, - unsigned long addr, unsigned int pdshift, - unsigned int flags, - struct follow_page_context *ctx) -{ - return NULL; -} -#endif /* CONFIG_ARCH_HAS_HUGEPD */ - +#endif /* CONFIG_HAVE_GUP_FAST */ static struct page *no_page_table(struct vm_area_struct *vma, unsigned int flags, unsigned long address) @@ -786,7 +688,7 @@ static inline bool can_follow_write_pmd(pmd_t pmd, struct page *page, return false; /* ... and a write-fault isn't required for other reasons. */ - if (vma_soft_dirty_enabled(vma) && !pmd_soft_dirty(pmd)) + if (pmd_needs_soft_dirty_wp(vma, pmd)) return false; return !userfaultfd_huge_pmd_wp(vma, pmd); } @@ -907,7 +809,7 @@ static inline bool can_follow_write_pte(pte_t pte, struct page *page, return false; /* ... and a write-fault isn't required for other reasons. */ - if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte)) + if (pte_needs_soft_dirty_wp(vma, pte)) return false; return !userfaultfd_pte_wp(vma, pte); } @@ -1040,9 +942,6 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, return no_page_table(vma, flags, address); if (!pmd_present(pmdval)) return no_page_table(vma, flags, address); - if (unlikely(is_hugepd(__hugepd(pmd_val(pmdval))))) - return follow_hugepd(vma, __hugepd(pmd_val(pmdval)), - address, PMD_SHIFT, flags, ctx); if (pmd_devmap(pmdval)) { ptl = pmd_lock(mm, pmd); page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap); @@ -1093,9 +992,6 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma, pud = READ_ONCE(*pudp); if (!pud_present(pud)) return no_page_table(vma, flags, address); - if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) - return follow_hugepd(vma, __hugepd(pud_val(pud)), - address, PUD_SHIFT, flags, ctx); if (pud_leaf(pud)) { ptl = pud_lock(mm, pudp); page = follow_huge_pud(vma, address, pudp, flags, ctx); @@ -1121,10 +1017,6 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma, p4d = READ_ONCE(*p4dp); BUILD_BUG_ON(p4d_leaf(p4d)); - if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) - return follow_hugepd(vma, __hugepd(p4d_val(p4d)), - address, P4D_SHIFT, flags, ctx); - if (!p4d_present(p4d) || p4d_bad(p4d)) return no_page_table(vma, flags, address); @@ -1168,10 +1060,7 @@ static struct page *follow_page_mask(struct vm_area_struct *vma, ctx->page_mask = 0; pgd = pgd_offset(mm, address); - if (unlikely(is_hugepd(__hugepd(pgd_val(*pgd))))) - page = follow_hugepd(vma, __hugepd(pgd_val(*pgd)), - address, PGDIR_SHIFT, flags, ctx); - else if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) + if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) page = no_page_table(vma, flags, address); else page = follow_p4d_mask(vma, address, pgd, flags, ctx); @@ -2394,19 +2283,19 @@ struct page *get_dump_page(unsigned long addr) #ifdef CONFIG_MIGRATION /* - * Returns the number of collected pages. Return value is always >= 0. + * Returns the number of collected folios. Return value is always >= 0. */ -static unsigned long collect_longterm_unpinnable_pages( - struct list_head *movable_page_list, - unsigned long nr_pages, - struct page **pages) +static unsigned long collect_longterm_unpinnable_folios( + struct list_head *movable_folio_list, + unsigned long nr_folios, + struct folio **folios) { unsigned long i, collected = 0; struct folio *prev_folio = NULL; bool drain_allow = true; - for (i = 0; i < nr_pages; i++) { - struct folio *folio = page_folio(pages[i]); + for (i = 0; i < nr_folios; i++) { + struct folio *folio = folios[i]; if (folio == prev_folio) continue; @@ -2421,7 +2310,7 @@ static unsigned long collect_longterm_unpinnable_pages( continue; if (folio_test_hugetlb(folio)) { - isolate_hugetlb(folio, movable_page_list); + isolate_hugetlb(folio, movable_folio_list); continue; } @@ -2433,7 +2322,7 @@ static unsigned long collect_longterm_unpinnable_pages( if (!folio_isolate_lru(folio)) continue; - list_add_tail(&folio->lru, movable_page_list); + list_add_tail(&folio->lru, movable_folio_list); node_stat_mod_folio(folio, NR_ISOLATED_ANON + folio_is_file_lru(folio), folio_nr_pages(folio)); @@ -2443,27 +2332,28 @@ static unsigned long collect_longterm_unpinnable_pages( } /* - * Unpins all pages and migrates device coherent pages and movable_page_list. - * Returns -EAGAIN if all pages were successfully migrated or -errno for failure - * (or partial success). + * Unpins all folios and migrates device coherent folios and movable_folio_list. + * Returns -EAGAIN if all folios were successfully migrated or -errno for + * failure (or partial success). */ -static int migrate_longterm_unpinnable_pages( - struct list_head *movable_page_list, - unsigned long nr_pages, - struct page **pages) +static int migrate_longterm_unpinnable_folios( + struct list_head *movable_folio_list, + unsigned long nr_folios, + struct folio **folios) { int ret; unsigned long i; - for (i = 0; i < nr_pages; i++) { - struct folio *folio = page_folio(pages[i]); + for (i = 0; i < nr_folios; i++) { + struct folio *folio = folios[i]; if (folio_is_device_coherent(folio)) { /* - * Migration will fail if the page is pinned, so convert - * the pin on the source page to a normal reference. + * Migration will fail if the folio is pinned, so + * convert the pin on the source folio to a normal + * reference. */ - pages[i] = NULL; + folios[i] = NULL; folio_get(folio); gup_put_folio(folio, 1, FOLL_PIN); @@ -2476,24 +2366,24 @@ static int migrate_longterm_unpinnable_pages( } /* - * We can't migrate pages with unexpected references, so drop + * We can't migrate folios with unexpected references, so drop * the reference obtained by __get_user_pages_locked(). - * Migrating pages have been added to movable_page_list after + * Migrating folios have been added to movable_folio_list after * calling folio_isolate_lru() which takes a reference so the - * page won't be freed if it's migrating. + * folio won't be freed if it's migrating. */ - unpin_user_page(pages[i]); - pages[i] = NULL; + unpin_folio(folios[i]); + folios[i] = NULL; } - if (!list_empty(movable_page_list)) { + if (!list_empty(movable_folio_list)) { struct migration_target_control mtc = { .nid = NUMA_NO_NODE, .gfp_mask = GFP_USER | __GFP_NOWARN, .reason = MR_LONGTERM_PIN, }; - if (migrate_pages(movable_page_list, alloc_migration_target, + if (migrate_pages(movable_folio_list, alloc_migration_target, NULL, (unsigned long)&mtc, MIGRATE_SYNC, MR_LONGTERM_PIN, NULL)) { ret = -ENOMEM; @@ -2501,48 +2391,71 @@ static int migrate_longterm_unpinnable_pages( } } - putback_movable_pages(movable_page_list); + putback_movable_pages(movable_folio_list); return -EAGAIN; err: - for (i = 0; i < nr_pages; i++) - if (pages[i]) - unpin_user_page(pages[i]); - putback_movable_pages(movable_page_list); + unpin_folios(folios, nr_folios); + putback_movable_pages(movable_folio_list); return ret; } /* - * Check whether all pages are *allowed* to be pinned. Rather confusingly, all - * pages in the range are required to be pinned via FOLL_PIN, before calling - * this routine. + * Check whether all folios are *allowed* to be pinned indefinitely (longterm). + * Rather confusingly, all folios in the range are required to be pinned via + * FOLL_PIN, before calling this routine. * - * If any pages in the range are not allowed to be pinned, then this routine - * will migrate those pages away, unpin all the pages in the range and return + * If any folios in the range are not allowed to be pinned, then this routine + * will migrate those folios away, unpin all the folios in the range and return * -EAGAIN. The caller should re-pin the entire range with FOLL_PIN and then * call this routine again. * * If an error other than -EAGAIN occurs, this indicates a migration failure. * The caller should give up, and propagate the error back up the call stack. * - * If everything is OK and all pages in the range are allowed to be pinned, then - * this routine leaves all pages pinned and returns zero for success. + * If everything is OK and all folios in the range are allowed to be pinned, + * then this routine leaves all folios pinned and returns zero for success. */ -static long check_and_migrate_movable_pages(unsigned long nr_pages, - struct page **pages) +static long check_and_migrate_movable_folios(unsigned long nr_folios, + struct folio **folios) { unsigned long collected; - LIST_HEAD(movable_page_list); + LIST_HEAD(movable_folio_list); - collected = collect_longterm_unpinnable_pages(&movable_page_list, - nr_pages, pages); + collected = collect_longterm_unpinnable_folios(&movable_folio_list, + nr_folios, folios); if (!collected) return 0; - return migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages, - pages); + return migrate_longterm_unpinnable_folios(&movable_folio_list, + nr_folios, folios); +} + +/* + * This routine just converts all the pages in the @pages array to folios and + * calls check_and_migrate_movable_folios() to do the heavy lifting. + * + * Please see the check_and_migrate_movable_folios() documentation for details. + */ +static long check_and_migrate_movable_pages(unsigned long nr_pages, + struct page **pages) +{ + struct folio **folios; + long i, ret; + + folios = kmalloc_array(nr_pages, sizeof(*folios), GFP_KERNEL); + if (!folios) + return -ENOMEM; + + for (i = 0; i < nr_pages; i++) + folios[i] = page_folio(pages[i]); + + ret = check_and_migrate_movable_folios(nr_pages, folios); + + kfree(folios); + return ret; } #else static long check_and_migrate_movable_pages(unsigned long nr_pages, @@ -2550,6 +2463,12 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages, { return 0; } + +static long check_and_migrate_movable_folios(unsigned long nr_folios, + struct folio **folios) +{ + return 0; +} #endif /* CONFIG_MIGRATION */ /* @@ -3283,15 +3202,6 @@ static int gup_fast_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, pages, nr)) return 0; - } else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) { - /* - * architecture have different format for hugetlbfs - * pmd format and THP pmd format - */ - if (gup_hugepd(NULL, __hugepd(pmd_val(pmd)), addr, - PMD_SHIFT, next, flags, pages, nr, - true) != 1) - return 0; } else if (!gup_fast_pte_range(pmd, pmdp, addr, next, flags, pages, nr)) return 0; @@ -3318,11 +3228,6 @@ static int gup_fast_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, if (!gup_fast_pud_leaf(pud, pudp, addr, next, flags, pages, nr)) return 0; - } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) { - if (gup_hugepd(NULL, __hugepd(pud_val(pud)), addr, - PUD_SHIFT, next, flags, pages, nr, - true) != 1) - return 0; } else if (!gup_fast_pmd_range(pudp, pud, addr, next, flags, pages, nr)) return 0; @@ -3346,13 +3251,8 @@ static int gup_fast_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, if (!p4d_present(p4d)) return 0; BUILD_BUG_ON(p4d_leaf(p4d)); - if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) { - if (gup_hugepd(NULL, __hugepd(p4d_val(p4d)), addr, - P4D_SHIFT, next, flags, pages, nr, - true) != 1) - return 0; - } else if (!gup_fast_pud_range(p4dp, p4d, addr, next, flags, - pages, nr)) + if (!gup_fast_pud_range(p4dp, p4d, addr, next, flags, + pages, nr)) return 0; } while (p4dp++, addr = next, addr != end); @@ -3376,11 +3276,6 @@ static void gup_fast_pgd_range(unsigned long addr, unsigned long end, if (!gup_fast_pgd_leaf(pgd, pgdp, addr, next, flags, pages, nr)) return; - } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { - if (gup_hugepd(NULL, __hugepd(pgd_val(pgd)), addr, - PGDIR_SHIFT, next, flags, pages, nr, - true) != 1) - return; } else if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags, pages, nr)) return; @@ -3687,3 +3582,140 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages, &locked, gup_flags); } EXPORT_SYMBOL(pin_user_pages_unlocked); + +/** + * memfd_pin_folios() - pin folios associated with a memfd + * @memfd: the memfd whose folios are to be pinned + * @start: the first memfd offset + * @end: the last memfd offset (inclusive) + * @folios: array that receives pointers to the folios pinned + * @max_folios: maximum number of entries in @folios + * @offset: the offset into the first folio + * + * Attempt to pin folios associated with a memfd in the contiguous range + * [start, end]. Given that a memfd is either backed by shmem or hugetlb, + * the folios can either be found in the page cache or need to be allocated + * if necessary. Once the folios are located, they are all pinned via + * FOLL_PIN and @offset is populatedwith the offset into the first folio. + * And, eventually, these pinned folios must be released either using + * unpin_folios() or unpin_folio(). + * + * It must be noted that the folios may be pinned for an indefinite amount + * of time. And, in most cases, the duration of time they may stay pinned + * would be controlled by the userspace. This behavior is effectively the + * same as using FOLL_LONGTERM with other GUP APIs. + * + * Returns number of folios pinned, which could be less than @max_folios + * as it depends on the folio sizes that cover the range [start, end]. + * If no folios were pinned, it returns -errno. + */ +long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, + struct folio **folios, unsigned int max_folios, + pgoff_t *offset) +{ + unsigned int flags, nr_folios, nr_found; + unsigned int i, pgshift = PAGE_SHIFT; + pgoff_t start_idx, end_idx, next_idx; + struct folio *folio = NULL; + struct folio_batch fbatch; + struct hstate *h; + long ret = -EINVAL; + + if (start < 0 || start > end || !max_folios) + return -EINVAL; + + if (!memfd) + return -EINVAL; + + if (!shmem_file(memfd) && !is_file_hugepages(memfd)) + return -EINVAL; + + if (end >= i_size_read(file_inode(memfd))) + return -EINVAL; + + if (is_file_hugepages(memfd)) { + h = hstate_file(memfd); + pgshift = huge_page_shift(h); + } + + flags = memalloc_pin_save(); + do { + nr_folios = 0; + start_idx = start >> pgshift; + end_idx = end >> pgshift; + if (is_file_hugepages(memfd)) { + start_idx <<= huge_page_order(h); + end_idx <<= huge_page_order(h); + } + + folio_batch_init(&fbatch); + while (start_idx <= end_idx && nr_folios < max_folios) { + /* + * In most cases, we should be able to find the folios + * in the page cache. If we cannot find them for some + * reason, we try to allocate them and add them to the + * page cache. + */ + nr_found = filemap_get_folios_contig(memfd->f_mapping, + &start_idx, + end_idx, + &fbatch); + if (folio) { + folio_put(folio); + folio = NULL; + } + + next_idx = 0; + for (i = 0; i < nr_found; i++) { + /* + * As there can be multiple entries for a + * given folio in the batch returned by + * filemap_get_folios_contig(), the below + * check is to ensure that we pin and return a + * unique set of folios between start and end. + */ + if (next_idx && + next_idx != folio_index(fbatch.folios[i])) + continue; + + folio = page_folio(&fbatch.folios[i]->page); + + if (try_grab_folio(folio, 1, FOLL_PIN)) { + folio_batch_release(&fbatch); + ret = -EINVAL; + goto err; + } + + if (nr_folios == 0) + *offset = offset_in_folio(folio, start); + + folios[nr_folios] = folio; + next_idx = folio_next_index(folio); + if (++nr_folios == max_folios) + break; + } + + folio = NULL; + folio_batch_release(&fbatch); + if (!nr_found) { + folio = memfd_alloc_folio(memfd, start_idx); + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); + if (ret != -EEXIST) + goto err; + } + } + } + + ret = check_and_migrate_movable_folios(nr_folios, folios); + } while (ret == -EAGAIN); + + memalloc_pin_restore(flags); + return ret ? ret : nr_folios; +err: + memalloc_pin_restore(flags); + unpin_folios(folios, nr_folios); + + return ret; +} +EXPORT_SYMBOL_GPL(memfd_pin_folios); |