diff options
author | Christoph Hellwig <hch@lst.de> | 2023-03-07 17:34:10 +0300 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-06 05:42:42 +0300 |
commit | 66dabbb65d673aef40dd17bf62c042be8f6d4a4b (patch) | |
tree | a14c48222ab659cc6a9344ca6a1468a09c09eb42 /mm | |
parent | 48c9d11375fc66f1e59d0e9b27d121e015a50904 (diff) | |
download | linux-66dabbb65d673aef40dd17bf62c042be8f6d4a4b.tar.xz |
mm: return an ERR_PTR from __filemap_get_folio
Instead of returning NULL for all errors, distinguish between:
- no entry found and not asked to allocated (-ENOENT)
- failed to allocate memory (-ENOMEM)
- would block (-EAGAIN)
so that callers don't have to guess the error based on the passed in
flags.
Also pass through the error through the direct callers: filemap_get_folio,
filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio.
[hch@lst.de: fix null-pointer deref]
Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de
Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004
Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nilfs2]
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/filemap.c | 14 | ||||
-rw-r--r-- | mm/folio-compat.c | 2 | ||||
-rw-r--r-- | mm/huge_memory.c | 2 | ||||
-rw-r--r-- | mm/hugetlb.c | 6 | ||||
-rw-r--r-- | mm/memcontrol.c | 2 | ||||
-rw-r--r-- | mm/mincore.c | 2 | ||||
-rw-r--r-- | mm/shmem.c | 4 | ||||
-rw-r--r-- | mm/swap_state.c | 17 | ||||
-rw-r--r-- | mm/swapfile.c | 4 | ||||
-rw-r--r-- | mm/truncate.c | 15 |
10 files changed, 38 insertions, 30 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index ac161b50f5bc..a34abfe8c654 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1907,7 +1907,7 @@ out: * * If there is a page cache page, it is returned with an increased refcount. * - * Return: The found folio or %NULL otherwise. + * Return: The found folio or an ERR_PTR() otherwise. */ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, int fgp_flags, gfp_t gfp) @@ -1925,7 +1925,7 @@ repeat: if (fgp_flags & FGP_NOWAIT) { if (!folio_trylock(folio)) { folio_put(folio); - return NULL; + return ERR_PTR(-EAGAIN); } } else { folio_lock(folio); @@ -1964,7 +1964,7 @@ no_page: folio = filemap_alloc_folio(gfp, 0); if (!folio) - return NULL; + return ERR_PTR(-ENOMEM); if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP)))) fgp_flags |= FGP_LOCK; @@ -1989,6 +1989,8 @@ no_page: folio_unlock(folio); } + if (!folio) + return ERR_PTR(-ENOENT); return folio; } EXPORT_SYMBOL(__filemap_get_folio); @@ -3258,7 +3260,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) * Do we have something in the page cache already? */ folio = filemap_get_folio(mapping, index); - if (likely(folio)) { + if (likely(!IS_ERR(folio))) { /* * We found the page, so try async readahead before waiting for * the lock. @@ -3287,7 +3289,7 @@ retry_find: folio = __filemap_get_folio(mapping, index, FGP_CREAT|FGP_FOR_MMAP, vmf->gfp_mask); - if (!folio) { + if (IS_ERR(folio)) { if (fpin) goto out_retry; filemap_invalidate_unlock_shared(mapping); @@ -3638,7 +3640,7 @@ static struct folio *do_read_cache_folio(struct address_space *mapping, filler = mapping->a_ops->read_folio; repeat: folio = filemap_get_folio(mapping, index); - if (!folio) { + if (IS_ERR(folio)) { folio = filemap_alloc_folio(gfp, 0); if (!folio) return ERR_PTR(-ENOMEM); diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 1754daa85d35..2511c055a35f 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -97,7 +97,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, struct folio *folio; folio = __filemap_get_folio(mapping, index, fgp_flags, gfp); - if (!folio) + if (IS_ERR(folio)) return NULL; return folio_file_page(folio, index); } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 70008dd7f215..2d860e70fe88 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3092,7 +3092,7 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, struct folio *folio = filemap_get_folio(mapping, index); nr_pages = 1; - if (!folio) + if (IS_ERR(folio)) continue; if (!folio_test_large(folio)) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 07abcb6eb203..712e32b38295 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5780,7 +5780,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, */ new_folio = false; folio = filemap_lock_folio(mapping, idx); - if (!folio) { + if (IS_ERR(folio)) { size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto out; @@ -6071,6 +6071,8 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, vma_end_reservation(h, vma, haddr); pagecache_folio = filemap_lock_folio(mapping, idx); + if (IS_ERR(pagecache_folio)) + pagecache_folio = NULL; } ptl = huge_pte_lock(h, mm, ptep); @@ -6182,7 +6184,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, if (is_continue) { ret = -EFAULT; folio = filemap_lock_folio(mapping, idx); - if (!folio) + if (IS_ERR(folio)) goto out; folio_in_pagecache = true; } else if (!*pagep) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 13ec89c45389..0524add35cae 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5705,7 +5705,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, /* shmem/tmpfs may report page out on swap: account for that too. */ index = linear_page_index(vma, addr); folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index); - if (!folio) + if (IS_ERR(folio)) return NULL; return folio_file_page(folio, index); } diff --git a/mm/mincore.c b/mm/mincore.c index d359650b0f75..2d5be013a25a 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -61,7 +61,7 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t index) * tmpfs's .fault). So swapped out tmpfs mappings are tested here. */ folio = filemap_get_incore_folio(mapping, index); - if (folio) { + if (!IS_ERR(folio)) { present = folio_test_uptodate(folio); folio_put(folio); } diff --git a/mm/shmem.c b/mm/shmem.c index 93cb39852a16..fa6e38f2f55f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -605,7 +605,7 @@ next: index = (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT; folio = filemap_get_folio(inode->i_mapping, index); - if (!folio) + if (IS_ERR(folio)) goto drop; /* No huge page at the end of the file: nothing to split */ @@ -3214,7 +3214,7 @@ static const char *shmem_get_link(struct dentry *dentry, if (!dentry) { folio = filemap_get_folio(inode->i_mapping, 0); - if (!folio) + if (IS_ERR(folio)) return ERR_PTR(-ECHILD); if (PageHWPoison(folio_page(folio, 0)) || !folio_test_uptodate(folio)) { diff --git a/mm/swap_state.c b/mm/swap_state.c index 92234f4b51d2..b76a65ac28b3 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -336,7 +336,7 @@ struct folio *swap_cache_get_folio(swp_entry_t entry, struct folio *folio; folio = filemap_get_folio(swap_address_space(entry), swp_offset(entry)); - if (folio) { + if (!IS_ERR(folio)) { bool vma_ra = swap_use_vma_readahead(); bool readahead; @@ -366,6 +366,8 @@ struct folio *swap_cache_get_folio(swp_entry_t entry, if (!vma || !vma_ra) atomic_inc(&swapin_readahead_hits); } + } else { + folio = NULL; } return folio; @@ -388,23 +390,24 @@ struct folio *filemap_get_incore_folio(struct address_space *mapping, struct swap_info_struct *si; struct folio *folio = filemap_get_entry(mapping, index); + if (!folio) + return ERR_PTR(-ENOENT); if (!xa_is_value(folio)) - goto out; + return folio; if (!shmem_mapping(mapping)) - return NULL; + return ERR_PTR(-ENOENT); swp = radix_to_swp_entry(folio); /* There might be swapin error entries in shmem mapping. */ if (non_swap_entry(swp)) - return NULL; + return ERR_PTR(-ENOENT); /* Prevent swapoff from happening to us */ si = get_swap_device(swp); if (!si) - return NULL; + return ERR_PTR(-ENOENT); index = swp_offset(swp); folio = filemap_get_folio(swap_address_space(swp), index); put_swap_device(si); -out: return folio; } @@ -431,7 +434,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, folio = filemap_get_folio(swap_address_space(entry), swp_offset(entry)); put_swap_device(si); - if (folio) + if (!IS_ERR(folio)) return folio_file_page(folio, swp_offset(entry)); /* diff --git a/mm/swapfile.c b/mm/swapfile.c index c1b97436f811..00b3e46becad 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -136,7 +136,7 @@ static int __try_to_reclaim_swap(struct swap_info_struct *si, int ret = 0; folio = filemap_get_folio(swap_address_space(entry), offset); - if (!folio) + if (IS_ERR(folio)) return 0; /* * When this function is called from scan_swap_map_slots() and it's @@ -2095,7 +2095,7 @@ retry: entry = swp_entry(type, i); folio = filemap_get_folio(swap_address_space(entry), i); - if (!folio) + if (IS_ERR(folio)) continue; /* diff --git a/mm/truncate.c b/mm/truncate.c index 7b4ea4c4a46b..86de31ed4d32 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -375,7 +375,7 @@ void truncate_inode_pages_range(struct address_space *mapping, same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT); folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0); - if (folio) { + if (!IS_ERR(folio)) { same_folio = lend < folio_pos(folio) + folio_size(folio); if (!truncate_inode_partial_folio(folio, lstart, lend)) { start = folio->index + folio_nr_pages(folio); @@ -387,14 +387,15 @@ void truncate_inode_pages_range(struct address_space *mapping, folio = NULL; } - if (!same_folio) + if (!same_folio) { folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT, FGP_LOCK, 0); - if (folio) { - if (!truncate_inode_partial_folio(folio, lstart, lend)) - end = folio->index; - folio_unlock(folio); - folio_put(folio); + if (!IS_ERR(folio)) { + if (!truncate_inode_partial_folio(folio, lstart, lend)) + end = folio->index; + folio_unlock(folio); + folio_put(folio); + } } index = start; |