[RFC PATCH v1 07/57] fs: Introduce MAX_BUF_PER_PAGE_SIZE_MAX for array sizing
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From: Ryan Roberts <ryan.roberts@arm.com>
Date: 2024-10-14 10:59:49
Also in:
linux-ext4, linux-fsdevel, linux-mm, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest, vfat/fat/msdos filesystem · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds, OGAWA Hirofumi
To prepare for supporting boot-time page size selection, refactor code to remove assumptions about PAGE_SIZE being compile-time constant. Code intended to be equivalent when compile-time page size is active. Code that previously defined arrays with MAX_BUF_PER_PAGE will no longer work with boot-time page selection because PAGE_SIZE is not known at compile-time. Introduce MAX_BUF_PER_PAGE_SIZE_MAX for this purpose, which is the requirement in the limit when PAGE_SIZE_MAX is the selected page size. Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ (local) fs/buffer.c | 2 +- fs/ext4/move_extent.c | 2 +- fs/ext4/readpage.c | 2 +- fs/fat/dir.c | 4 ++-- fs/fat/fatent.c | 4 ++-- include/linux/buffer_head.h | 1 + 6 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index e55ad471c5306..f00542ad43a5c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c@@ -2371,7 +2371,7 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block) { struct inode *inode = folio->mapping->host; sector_t iblock, lblock; - struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; + struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE_SIZE_MAX]; size_t blocksize; int nr, i; int fully_mapped = 1;
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 204f53b236229..68304426c6f45 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c@@ -172,7 +172,7 @@ mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to) { struct inode *inode = folio->mapping->host; sector_t block; - struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; + struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE_SIZE_MAX]; unsigned int blocksize, block_start, block_end; int i, err, nr = 0, partial = 0; BUG_ON(!folio_test_locked(folio));
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 8494492582abe..5808d85096aeb 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c@@ -221,7 +221,7 @@ int ext4_mpage_readpages(struct inode *inode, sector_t block_in_file; sector_t last_block; sector_t last_block_in_file; - sector_t blocks[MAX_BUF_PER_PAGE]; + sector_t blocks[MAX_BUF_PER_PAGE_SIZE_MAX]; unsigned page_block; struct block_device *bdev = inode->i_sb->s_bdev; int length;
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index acbec5bdd5210..f3e96ecf21c92 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c@@ -1146,7 +1146,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts) { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); - struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct buffer_head *bhs[MAX_BUF_PER_PAGE_SIZE_MAX]; struct msdos_dir_entry *de; sector_t blknr; __le16 date, time;
@@ -1213,7 +1213,7 @@ static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); - struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct buffer_head *bhs[MAX_BUF_PER_PAGE_SIZE_MAX]; sector_t blknr, start_blknr, last_blknr; unsigned long size, copy; int err, i, n, offset, cluster[2];
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 1db348f8f887a..322cf5b8e5590 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c@@ -469,7 +469,7 @@ int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) struct msdos_sb_info *sbi = MSDOS_SB(sb); const struct fatent_operations *ops = sbi->fatent_ops; struct fat_entry fatent, prev_ent; - struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct buffer_head *bhs[MAX_BUF_PER_PAGE_SIZE_MAX]; int i, count, err, nr_bhs, idx_clus; BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */
@@ -557,7 +557,7 @@ int fat_free_clusters(struct inode *inode, int cluster) struct msdos_sb_info *sbi = MSDOS_SB(sb); const struct fatent_operations *ops = sbi->fatent_ops; struct fat_entry fatent; - struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct buffer_head *bhs[MAX_BUF_PER_PAGE_SIZE_MAX]; int i, err, nr_bhs; int first_cl = cluster, dirty_fsinfo = 0;
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 14acf1bbe0ce6..5dff4837b76cd 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h@@ -41,6 +41,7 @@ enum bh_state_bits { }; #define MAX_BUF_PER_PAGE (PAGE_SIZE / 512) +#define MAX_BUF_PER_PAGE_SIZE_MAX (PAGE_SIZE_MAX / 512) struct page; struct buffer_head;
--
2.43.0