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btrfs: replace kmap() with kmap_local_page() in lzo.c

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The use of kmap() is being deprecated in favor of kmap_local_page() where
it is feasible. With kmap_local_page(), the mapping is per thread, CPU
local and not globally visible.

Therefore, use kmap_local_page() / kunmap_local() in lzo.c wherever the
mappings are per thread and not globally visible.

Tested on QEMU + KVM 32 bits VM with 4GB of RAM and HIGHMEM64G enabled.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Fabio M. De Francesco 2022-05-31 16:53:34 +02:00 committed by David Sterba
parent 70826b6bd5
commit 51c0674a56
1 changed files with 12 additions and 16 deletions
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28
fs/btrfs/lzo.c
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@ -155,7 +155,7 @@ static int copy_compressed_data_to_page(char *compressed_data,
out_pages[*cur_out / PAGE_SIZE] = cur_page;
}
kaddr = kmap(cur_page);
kaddr = kmap_local_page(cur_page);
write_compress_length(kaddr + offset_in_page(*cur_out),
compressed_size);
*cur_out += LZO_LEN;
@ -167,7 +167,7 @@ static int copy_compressed_data_to_page(char *compressed_data,
u32 copy_len = min_t(u32, sectorsize - *cur_out % sectorsize,
orig_out + compressed_size - *cur_out);
kunmap(cur_page);
kunmap_local(kaddr);
if ((*cur_out / PAGE_SIZE) >= max_nr_page)
return -E2BIG;
@ -180,7 +180,7 @@ static int copy_compressed_data_to_page(char *compressed_data,
return -ENOMEM;
out_pages[*cur_out / PAGE_SIZE] = cur_page;
}
kaddr = kmap(cur_page);
kaddr = kmap_local_page(cur_page);
memcpy(kaddr + offset_in_page(*cur_out),
compressed_data + *cur_out - orig_out, copy_len);
@ -202,7 +202,7 @@ static int copy_compressed_data_to_page(char *compressed_data,
*cur_out += sector_bytes_left;
out:
kunmap(cur_page);
kunmap_local(kaddr);
return 0;
}
@ -248,12 +248,12 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
/* Compress at most one sector of data each time */
in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);
ASSERT(in_len);
data_in = kmap(page_in);
data_in = kmap_local_page(page_in);
ret = lzo1x_1_compress(data_in +
offset_in_page(cur_in), in_len,
workspace->cbuf, &out_len,
workspace->mem);
kunmap(page_in);
kunmap_local(data_in);
if (ret < 0) {
pr_debug("BTRFS: lzo in loop returned %d\n", ret);
ret = -EIO;
@ -310,7 +310,6 @@ static void copy_compressed_segment(struct compressed_bio *cb,
u32 orig_in = *cur_in;
while (*cur_in < orig_in + len) {
char *kaddr;
struct page *cur_page;
u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
orig_in + len - *cur_in);
@ -318,11 +317,8 @@ static void copy_compressed_segment(struct compressed_bio *cb,
ASSERT(copy_len);
cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE];
kaddr = kmap(cur_page);
memcpy(dest + *cur_in - orig_in,
kaddr + offset_in_page(*cur_in),
copy_len);
kunmap(cur_page);
memcpy_from_page(dest + *cur_in - orig_in, cur_page,
offset_in_page(*cur_in), copy_len);
*cur_in += copy_len;
}
@ -342,9 +338,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
/* Bytes decompressed so far */
u32 cur_out = 0;
kaddr = kmap(cb->compressed_pages[0]);
kaddr = kmap_local_page(cb->compressed_pages[0]);
len_in = read_compress_length(kaddr);
kunmap(cb->compressed_pages[0]);
kunmap_local(kaddr);
cur_in += LZO_LEN;
/*
@ -378,9 +374,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
(cur_in + LZO_LEN - 1) / sectorsize);
cur_page = cb->compressed_pages[cur_in / PAGE_SIZE];
ASSERT(cur_page);
kaddr = kmap(cur_page);
kaddr = kmap_local_page(cur_page);
seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
kunmap(cur_page);
kunmap_local(kaddr);
cur_in += LZO_LEN;
if (seg_len > WORKSPACE_CBUF_LENGTH) {