The patch titled Subject: buffer: fix more functions for block size > PAGE_SIZE has been added to the -mm mm-unstable branch. Its filename is buffer-fix-more-functions-for-block-size-page_size.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-fix-more-functions-for-block-size-page_size.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: buffer: fix more functions for block size > PAGE_SIZE Date: Thu, 9 Nov 2023 21:06:08 +0000 Both __block_write_full_folio() and block_read_full_folio() assumed that block size <= PAGE_SIZE. Replace the shift with a divide, which is probably cheaper than first calculating the shift. That lets us remove block_size_bits() as these were the last callers. Link: https://lkml.kernel.org/r/20231109210608.2252323-8-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx> Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/buffer.c | 27 ++++++--------------------- 1 file changed, 6 insertions(+), 21 deletions(-) --- a/fs/buffer.c~buffer-fix-more-functions-for-block-size-page_size +++ a/fs/buffer.c @@ -1742,19 +1742,6 @@ unlock_page: } EXPORT_SYMBOL(clean_bdev_aliases); -/* - * Size is a power-of-two in the range 512..PAGE_SIZE, - * and the case we care about most is PAGE_SIZE. - * - * So this *could* possibly be written with those - * constraints in mind (relevant mostly if some - * architecture has a slow bit-scan instruction) - */ -static inline int block_size_bits(unsigned int blocksize) -{ - return ilog2(blocksize); -} - static struct buffer_head *folio_create_buffers(struct folio *folio, struct inode *inode, unsigned int b_state) @@ -1807,7 +1794,7 @@ int __block_write_full_folio(struct inod sector_t block; sector_t last_block; struct buffer_head *bh, *head; - unsigned int blocksize, bbits; + size_t blocksize; int nr_underway = 0; blk_opf_t write_flags = wbc_to_write_flags(wbc); @@ -1826,10 +1813,9 @@ int __block_write_full_folio(struct inod bh = head; blocksize = bh->b_size; - bbits = block_size_bits(blocksize); - block = (sector_t)folio->index << (PAGE_SHIFT - bbits); - last_block = (i_size_read(inode) - 1) >> bbits; + block = div_u64(folio_pos(folio), blocksize); + last_block = div_u64(i_size_read(inode) - 1, blocksize); /* * Get all the dirty buffers mapped to disk addresses and @@ -2355,7 +2341,7 @@ int block_read_full_folio(struct folio * struct inode *inode = folio->mapping->host; sector_t iblock, lblock; struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; - unsigned int blocksize, bbits; + size_t blocksize; int nr, i; int fully_mapped = 1; bool page_error = false; @@ -2369,10 +2355,9 @@ int block_read_full_folio(struct folio * head = folio_create_buffers(folio, inode, 0); blocksize = head->b_size; - bbits = block_size_bits(blocksize); - iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits); - lblock = (limit+blocksize-1) >> bbits; + iblock = div_u64(folio_pos(folio), blocksize); + lblock = div_u64(limit + blocksize - 1, blocksize); bh = head; nr = 0; i = 0; _ Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are mm-add-folio_zero_tail-and-use-it-in-ext4.patch mm-add-folio_fill_tail-and-use-it-in-iomap.patch gfs2-convert-stuffed_readpage-to-stuffed_read_folio.patch mm-remove-test_set_page_writeback.patch afs-do-not-test-the-return-value-of-folio_start_writeback.patch smb-do-not-test-the-return-value-of-folio_start_writeback.patch mm-return-void-from-folio_start_writeback-and-related-functions.patch mm-make-mapping_evict_folio-the-preferred-way-to-evict-clean-folios.patch mm-convert-__do_fault-to-use-a-folio.patch mm-use-mapping_evict_folio-in-truncate_error_page.patch mm-convert-soft_offline_in_use_page-to-use-a-folio.patch mm-convert-isolate_page-to-mf_isolate_folio.patch mm-remove-invalidate_inode_page.patch buffer-return-bool-from-grow_dev_folio.patch buffer-calculate-block-number-inside-folio_init_buffers.patch buffer-fix-grow_buffers-for-block-size-page_size.patch buffer-cast-block-to-loff_t-before-shifting-it.patch buffer-fix-various-functions-for-block-size-page_size.patch buffer-handle-large-folios-in-__block_write_begin_int.patch buffer-fix-more-functions-for-block-size-page_size.patch