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authorKyle Spiers <ksspiers@google.com>2018-04-11 03:02:29 +0300
committerJan Kara <jack@suse.cz>2018-04-11 10:55:40 +0300
commit5ac7c2fd6e7102532104907c0df94abca826ec5c (patch)
tree541480a00b9870bb5b97328c8abca5897e7aa7c7
parent1aa3b3e0cbdb32439f04842e88fc7557a0777660 (diff)
downloadlinux-5ac7c2fd6e7102532104907c0df94abca826ec5c.tar.xz
isofs compress: Remove VLA usage
As part of the effort to remove VLAs from the kernel[1], this changes the allocation of the bhs and pages arrays from being on the stack to being kcalloc()ed. This also allows for the removal of the explicit zeroing of bhs. https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Kyle Spiers <ksspiers@google.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/isofs/compress.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/isofs/compress.c b/fs/isofs/compress.c
index 9bb2fe35799d..10205ececc27 100644
--- a/fs/isofs/compress.c
+++ b/fs/isofs/compress.c
@@ -20,6 +20,7 @@
#include <linux/init.h>
#include <linux/bio.h>
+#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/zlib.h>
@@ -59,7 +60,7 @@ static loff_t zisofs_uncompress_block(struct inode *inode, loff_t block_start,
>> bufshift;
int haveblocks;
blkcnt_t blocknum;
- struct buffer_head *bhs[needblocks + 1];
+ struct buffer_head **bhs;
int curbh, curpage;
if (block_size > deflateBound(1UL << zisofs_block_shift)) {
@@ -80,7 +81,11 @@ static loff_t zisofs_uncompress_block(struct inode *inode, loff_t block_start,
/* Because zlib is not thread-safe, do all the I/O at the top. */
blocknum = block_start >> bufshift;
- memset(bhs, 0, (needblocks + 1) * sizeof(struct buffer_head *));
+ bhs = kcalloc(needblocks + 1, sizeof(*bhs), GFP_KERNEL);
+ if (!bhs) {
+ *errp = -ENOMEM;
+ return 0;
+ }
haveblocks = isofs_get_blocks(inode, blocknum, bhs, needblocks);
ll_rw_block(REQ_OP_READ, 0, haveblocks, bhs);
@@ -190,6 +195,7 @@ z_eio:
b_eio:
for (i = 0; i < haveblocks; i++)
brelse(bhs[i]);
+ kfree(bhs);
return stream.total_out;
}
@@ -305,7 +311,7 @@ static int zisofs_readpage(struct file *file, struct page *page)
unsigned int zisofs_pages_per_cblock =
PAGE_SHIFT <= zisofs_block_shift ?
(1 << (zisofs_block_shift - PAGE_SHIFT)) : 0;
- struct page *pages[max_t(unsigned, zisofs_pages_per_cblock, 1)];
+ struct page **pages;
pgoff_t index = page->index, end_index;
end_index = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -330,6 +336,12 @@ static int zisofs_readpage(struct file *file, struct page *page)
full_page = 0;
pcount = 1;
}
+ pages = kcalloc(max_t(unsigned int, zisofs_pages_per_cblock, 1),
+ sizeof(*pages), GFP_KERNEL);
+ if (!pages) {
+ unlock_page(page);
+ return -ENOMEM;
+ }
pages[full_page] = page;
for (i = 0; i < pcount; i++, index++) {
@@ -357,6 +369,7 @@ static int zisofs_readpage(struct file *file, struct page *page)
}
/* At this point, err contains 0 or -EIO depending on the "critical" page */
+ kfree(pages);
return err;
}