From 01f2705daf5a36208e69d7cf95db9c330f843af6 Mon Sep 17 00:00:00 2001 From: Nate Diller Date: Wed, 9 May 2007 02:35:07 -0700 Subject: [PATCH] fs: convert core functions to zero_user_page It's very common for file systems to need to zero part or all of a page, the simplist way is just to use kmap_atomic() and memset(). There's actually a library function in include/linux/highmem.h that does exactly that, but it's confusingly named memclear_highpage_flush(), which is descriptive of *how* it does the work rather than what the *purpose* is. So this patchset renames the function to zero_user_page(), and calls it from the various places that currently open code it. This first patch introduces the new function call, and converts all the core kernel callsites, both the open-coded ones and the old memclear_highpage_flush() ones. Following this patch is a series of conversions for each file system individually, per AKPM, and finally a patch deprecating the old call. The diffstat below shows the entire patchset. [akpm@linux-foundation.org: fix a few things] Signed-off-by: Nate Diller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/loop.c | 6 +---- fs/buffer.c | 56 +++++++++-------------------------------- fs/direct-io.c | 8 ++---- fs/mpage.c | 15 ++++------- include/linux/highmem.h | 28 ++++++++++++++------- mm/filemap_xip.c | 7 +----- mm/truncate.c | 3 ++- 7 files changed, 42 insertions(+), 81 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index af6d7274a7..18cdd8c776 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -243,17 +243,13 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, transfer_result = lo_do_transfer(lo, WRITE, page, offset, bvec->bv_page, bv_offs, size, IV); if (unlikely(transfer_result)) { - char *kaddr; - /* * The transfer failed, but we still write the data to * keep prepare/commit calls balanced. */ printk(KERN_ERR "loop: transfer error block %llu\n", (unsigned long long)index); - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, size); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, size, KM_USER0); } flush_dcache_page(page); ret = aops->commit_write(file, page, offset, diff --git a/fs/buffer.c b/fs/buffer.c index eb820b82a6..fc2d763a8d 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1846,13 +1846,8 @@ static int __block_prepare_write(struct inode *inode, struct page *page, if (block_start >= to) break; if (buffer_new(bh)) { - void *kaddr; - clear_buffer_new(bh); - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr+block_start, 0, bh->b_size); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, block_start, bh->b_size, KM_USER0); set_buffer_uptodate(bh); mark_buffer_dirty(bh); } @@ -1940,10 +1935,8 @@ int block_read_full_page(struct page *page, get_block_t *get_block) SetPageError(page); } if (!buffer_mapped(bh)) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + i * blocksize, 0, blocksize); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, i * blocksize, blocksize, + KM_USER0); if (!err) set_buffer_uptodate(bh); continue; @@ -2086,7 +2079,6 @@ int cont_prepare_write(struct page *page, unsigned offset, long status; unsigned zerofrom; unsigned blocksize = 1 << inode->i_blkbits; - void *kaddr; while(page->index > (pgpos = *bytes>>PAGE_CACHE_SHIFT)) { status = -ENOMEM; @@ -2108,10 +2100,8 @@ int cont_prepare_write(struct page *page, unsigned offset, PAGE_CACHE_SIZE, get_block); if (status) goto out_unmap; - kaddr = kmap_atomic(new_page, KM_USER0); - memset(kaddr+zerofrom, 0, PAGE_CACHE_SIZE-zerofrom); - flush_dcache_page(new_page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, zerofrom, PAGE_CACHE_SIZE - zerofrom, + KM_USER0); generic_commit_write(NULL, new_page, zerofrom, PAGE_CACHE_SIZE); unlock_page(new_page); page_cache_release(new_page); @@ -2138,10 +2128,7 @@ int cont_prepare_write(struct page *page, unsigned offset, if (status) goto out1; if (zerofrom < offset) { - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr+zerofrom, 0, offset-zerofrom); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, zerofrom, offset - zerofrom, KM_USER0); __block_commit_write(inode, page, zerofrom, offset); } return 0; @@ -2340,10 +2327,7 @@ failed: * Error recovery is pretty slack. Clear the page and mark it dirty * so we'll later zero out any blocks which _were_ allocated. */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr, 0, PAGE_CACHE_SIZE); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0); SetPageUptodate(page); set_page_dirty(page); return ret; @@ -2382,7 +2366,6 @@ int nobh_writepage(struct page *page, get_block_t *get_block, loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; - void *kaddr; int ret; /* Is the page fully inside i_size? */ @@ -2413,10 +2396,7 @@ int nobh_writepage(struct page *page, get_block_t *get_block, * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, PAGE_CACHE_SIZE - offset, KM_USER0); out: ret = mpage_writepage(page, get_block, wbc); if (ret == -EAGAIN) @@ -2437,7 +2417,6 @@ int nobh_truncate_page(struct address_space *mapping, loff_t from) unsigned to; struct page *page; const struct address_space_operations *a_ops = mapping->a_ops; - char *kaddr; int ret = 0; if ((offset & (blocksize - 1)) == 0) @@ -2451,10 +2430,8 @@ int nobh_truncate_page(struct address_space *mapping, loff_t from) to = (offset + blocksize) & ~(blocksize - 1); ret = a_ops->prepare_write(NULL, page, offset, to); if (ret == 0) { - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, PAGE_CACHE_SIZE - offset, + KM_USER0); /* * It would be more correct to call aops->commit_write() * here, but this is more efficient. @@ -2480,7 +2457,6 @@ int block_truncate_page(struct address_space *mapping, struct inode *inode = mapping->host; struct page *page; struct buffer_head *bh; - void *kaddr; int err; blocksize = 1 << inode->i_blkbits; @@ -2534,11 +2510,7 @@ int block_truncate_page(struct address_space *mapping, goto unlock; } - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, length); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - + zero_user_page(page, offset, length, KM_USER0); mark_buffer_dirty(bh); err = 0; @@ -2559,7 +2531,6 @@ int block_write_full_page(struct page *page, get_block_t *get_block, loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; - void *kaddr; /* Is the page fully inside i_size? */ if (page->index < end_index) @@ -2585,10 +2556,7 @@ int block_write_full_page(struct page *page, get_block_t *get_block, * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, PAGE_CACHE_SIZE - offset, KM_USER0); return __block_write_full_page(inode, page, get_block, wbc); } diff --git a/fs/direct-io.c b/fs/direct-io.c index d9d0833444..8aa2d8b04e 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -867,7 +867,6 @@ static int do_direct_IO(struct dio *dio) do_holes: /* Handle holes */ if (!buffer_mapped(map_bh)) { - char *kaddr; loff_t i_size_aligned; /* AKPM: eargh, -ENOTBLK is a hack */ @@ -888,11 +887,8 @@ do_holes: page_cache_release(page); goto out; } - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + (block_in_page << blkbits), - 0, 1 << blkbits); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, block_in_page << blkbits, + 1 << blkbits, KM_USER0); dio->block_in_file++; block_in_page++; goto next_block; diff --git a/fs/mpage.c b/fs/mpage.c index fa2441f57b..0fb914fc2e 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -284,11 +284,9 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages, } if (first_hole != blocks_per_page) { - char *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + (first_hole << blkbits), 0, - PAGE_CACHE_SIZE - (first_hole << blkbits)); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, first_hole << blkbits, + PAGE_CACHE_SIZE - (first_hole << blkbits), + KM_USER0); if (first_hole == 0) { SetPageUptodate(page); unlock_page(page); @@ -576,14 +574,11 @@ page_is_mapped: * written out to the file." */ unsigned offset = i_size & (PAGE_CACHE_SIZE - 1); - char *kaddr; if (page->index > end_index || !offset) goto confused; - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, PAGE_CACHE_SIZE - offset, + KM_USER0); } /* diff --git a/include/linux/highmem.h b/include/linux/highmem.h index a515eb0afd..b5f2ab42d9 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -94,17 +94,27 @@ static inline void clear_highpage(struct page *page) /* * Same but also flushes aliased cache contents to RAM. + * + * This must be a macro because KM_USER0 and friends aren't defined if + * !CONFIG_HIGHMEM */ -static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size) +#define zero_user_page(page, offset, size, km_type) \ + do { \ + void *kaddr; \ + \ + BUG_ON((offset) + (size) > PAGE_SIZE); \ + \ + kaddr = kmap_atomic(page, km_type); \ + memset((char *)kaddr + (offset), 0, (size)); \ + flush_dcache_page(page); \ + kunmap_atomic(kaddr, (km_type)); \ + } while (0) + + +static inline void memclear_highpage_flush(struct page *page, + unsigned int offset, unsigned int size) { - void *kaddr; - - BUG_ON(offset + size > PAGE_SIZE); - - kaddr = kmap_atomic(page, KM_USER0); - memset((char *)kaddr + offset, 0, size); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_page(page, offset, size, KM_USER0); } #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index cbb335813e..1b49dab9b2 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -434,7 +434,6 @@ xip_truncate_page(struct address_space *mapping, loff_t from) unsigned blocksize; unsigned length; struct page *page; - void *kaddr; BUG_ON(!mapping->a_ops->get_xip_page); @@ -458,11 +457,7 @@ xip_truncate_page(struct address_space *mapping, loff_t from) else return PTR_ERR(page); } - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, length); - kunmap_atomic(kaddr, KM_USER0); - - flush_dcache_page(page); + zero_user_page(page, offset, length, KM_USER0); return 0; } EXPORT_SYMBOL_GPL(xip_truncate_page); diff --git a/mm/truncate.c b/mm/truncate.c index 0f4b6d18ab..4fbe1a2da5 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include /* grr. try_to_release_page, @@ -46,7 +47,7 @@ void do_invalidatepage(struct page *page, unsigned long offset) static inline void truncate_partial_page(struct page *page, unsigned partial) { - memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial); + zero_user_page(page, partial, PAGE_CACHE_SIZE - partial, KM_USER0); if (PagePrivate(page)) do_invalidatepage(page, partial); } -- 2.39.5