| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20220611135203.27992-1-fmdefrancesco@gmail.com>
Date: Sat, 11 Jun 2022 15:52:03 +0200
From: "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To: Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>,
Nick Terrell <terrelln@...com>, linux-btrfs@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: "Fabio M. De Francesco" <fmdefrancesco@...il.com>,
Filipe Manana <fdmanana@...nel.org>,
Ira Weiny <ira.weiny@...el.com>
Subject: [PATCH] btrfs: Replace kmap() with kmap_local_page() in zstd.c
The use of kmap() is being deprecated in favor of kmap_local_page(). With
kmap_local_page(), the mapping is per thread, CPU local and not globally
visible.
Therefore, use kmap_local_page() / kunmap_local() in zstd.c because in
this file the mappings are per thread and are not visible in other
contexts; meanwhile refactor zstd_compress_pages() to comply with nested
local mapping / unmapping ordering rules.
Tested with xfstests on a QEMU + KVM 32 bits VM with 4GB of RAM and
HIGHMEM64G enabled.
Cc: Filipe Manana <fdmanana@...nel.org>
Suggested-by: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
---
Thanks to Ira Weiny for his invaluable help and persevering support.
Thanks also to Filipe Manana for identifying a fundamental detail I had overlooked:
https://lore.kernel.org/lkml/20220611093411.GA3779054@falcondesktop/
tweed32:/usr/lib/xfstests # ./check -g compress
FSTYP -- btrfs
PLATFORM -- Linux/i686 tweed32 5.19.0-rc1-vanilla-debug+ #22 SMP PREEMPT_DYNAMIC Sat Jun 11 14:31:39 CEST 2022
MKFS_OPTIONS -- /dev/loop1
MOUNT_OPTIONS -- /dev/loop1 /mnt/scratch
btrfs/024 1s ... 0s
btrfs/026 3s ... 3s
btrfs/037 1s ... 1s
btrfs/038 1s ... 0s
btrfs/041 0s ... 1s
btrfs/062 34s ... 35s
btrfs/063 18s ... 18s
btrfs/067 33s ... 32s
btrfs/068 10s ... 10s
btrfs/070 [not run] btrfs and this test needs 5 or more disks in SCRATCH_DEV_POOL
btrfs/071 [not run] btrfs and this test needs 5 or more disks in SCRATCH_DEV_POOL
btrfs/072 33s ... 33s
btrfs/073 17s ... 15s
btrfs/074 36s ... 32s
btrfs/076 0s ... 0s
btrfs/103 1s ... 1s
btrfs/106 1s ... 1s
btrfs/109 1s ... 0s
btrfs/113 0s ... 1s
btrfs/138 43s ... 46s
btrfs/149 1s ... 1s
btrfs/183 1s ... 1s
btrfs/205 1s ... 1s
btrfs/234 3s ... 3s
btrfs/246 0s ... 0s
btrfs/251 1s ... 1s
Ran: btrfs/024 btrfs/026 btrfs/037 btrfs/038 btrfs/041 btrfs/062 btrfs/063 btrfs/067 btrfs/068 btrfs/070 btrfs/071 btrfs/072 btrfs/073 btrfs/074 btrfs/076 btrfs/103 btrfs/106 btrfs/109 btrfs/113 btrfs/138 btrfs/149 btrfs/183 btrfs/205 btrfs/234 btrfs/246 btrfs/251
Not run: btrfs/070 btrfs/071
Passed all 26 tests
fs/btrfs/zstd.c | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
index 0fe31a6f6e68..4d50eb3edce5 100644
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -391,6 +391,8 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
*out_pages = 0;
*total_out = 0;
*total_in = 0;
+ workspace->in_buf.src = NULL;
+ workspace->out_buf.dst = NULL;
/* Initialize the stream */
stream = zstd_init_cstream(¶ms, len, workspace->mem,
@@ -403,7 +405,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
/* map in the first page of input data */
in_page = find_get_page(mapping, start >> PAGE_SHIFT);
- workspace->in_buf.src = kmap(in_page);
+ workspace->in_buf.src = kmap_local_page(in_page);
workspace->in_buf.pos = 0;
workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
@@ -415,7 +417,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
goto out;
}
pages[nr_pages++] = out_page;
- workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.dst = kmap_local_page(out_page);
workspace->out_buf.pos = 0;
workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
@@ -450,9 +452,9 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
if (workspace->out_buf.pos == workspace->out_buf.size) {
tot_out += PAGE_SIZE;
max_out -= PAGE_SIZE;
- kunmap(out_page);
+ kunmap_local(workspace->out_buf.dst);
if (nr_pages == nr_dest_pages) {
- out_page = NULL;
+ workspace->out_buf.dst = NULL;
ret = -E2BIG;
goto out;
}
@@ -462,7 +464,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
goto out;
}
pages[nr_pages++] = out_page;
- workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.dst = kmap_local_page(out_page);
workspace->out_buf.pos = 0;
workspace->out_buf.size = min_t(size_t, max_out,
PAGE_SIZE);
@@ -477,15 +479,16 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
/* Check if we need more input */
if (workspace->in_buf.pos == workspace->in_buf.size) {
tot_in += PAGE_SIZE;
- kunmap(in_page);
+ kunmap_local(workspace->out_buf.dst);
+ kunmap_local((void *)workspace->in_buf.src);
put_page(in_page);
-
start += PAGE_SIZE;
len -= PAGE_SIZE;
in_page = find_get_page(mapping, start >> PAGE_SHIFT);
- workspace->in_buf.src = kmap(in_page);
+ workspace->in_buf.src = kmap_local_page(in_page);
workspace->in_buf.pos = 0;
workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
+ workspace->out_buf.dst = kmap_local_page(out_page);
}
}
while (1) {
@@ -510,9 +513,9 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
tot_out += PAGE_SIZE;
max_out -= PAGE_SIZE;
- kunmap(out_page);
+ kunmap_local(workspace->out_buf.dst);
if (nr_pages == nr_dest_pages) {
- out_page = NULL;
+ workspace->out_buf.dst = NULL;
ret = -E2BIG;
goto out;
}
@@ -522,7 +525,7 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
goto out;
}
pages[nr_pages++] = out_page;
- workspace->out_buf.dst = kmap(out_page);
+ workspace->out_buf.dst = kmap_local_page(out_page);
workspace->out_buf.pos = 0;
workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
}
@@ -538,12 +541,12 @@ int zstd_compress_pages(struct list_head *ws, struct address_space *mapping,
out:
*out_pages = nr_pages;
/* Cleanup */
- if (in_page) {
- kunmap(in_page);
+ if (workspace->out_buf.dst)
+ kunmap_local(workspace->out_buf.dst);
+ if (workspace->in_buf.src) {
+ kunmap_local((void *)workspace->in_buf.src);
put_page(in_page);
}
- if (out_page)
- kunmap(out_page);
return ret;
}
@@ -567,7 +570,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
goto done;
}
- workspace->in_buf.src = kmap(pages_in[page_in_index]);
+ workspace->in_buf.src = kmap_local_page(pages_in[page_in_index]);
workspace->in_buf.pos = 0;
workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
@@ -603,14 +606,15 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
break;
if (workspace->in_buf.pos == workspace->in_buf.size) {
- kunmap(pages_in[page_in_index++]);
+ kunmap_local((void *)workspace->in_buf.src);
+ page_in_index++;
if (page_in_index >= total_pages_in) {
workspace->in_buf.src = NULL;
ret = -EIO;
goto done;
}
srclen -= PAGE_SIZE;
- workspace->in_buf.src = kmap(pages_in[page_in_index]);
+ workspace->in_buf.src = kmap_local_page(pages_in[page_in_index]);
workspace->in_buf.pos = 0;
workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
}
@@ -619,7 +623,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
zero_fill_bio(cb->orig_bio);
done:
if (workspace->in_buf.src)
- kunmap(pages_in[page_in_index]);
+ kunmap_local((void *)workspace->in_buf.src);
return ret;
}
--
2.36.1
Powered by blists - more mailing lists