From 01f2705daf5a36208e69d7cf95db9c330f843af6 Mon Sep 17 00:00:00 2001 From: Nate Diller Date: Wed, 9 May 2007 02:35:07 -0700 Subject: 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 --- fs/buffer.c | 56 ++++++++++++-------------------------------------------- 1 file changed, 12 insertions(+), 44 deletions(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index eb820b82a636..fc2d763a8d78 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); } -- cgit v1.2.3