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>
diff --git a/fs/isofs/compress.c b/fs/isofs/compress.c
index 9bb2fe3..10205ec 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 @@
>> 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 @@
/* 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 @@
b_eio:
for (i = 0; i < haveblocks; i++)
brelse(bhs[i]);
+ kfree(bhs);
return stream.total_out;
}
@@ -305,7 +311,7 @@
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 @@
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 @@
}
/* At this point, err contains 0 or -EIO depending on the "critical" page */
+ kfree(pages);
return err;
}