From: Phillip Lougher <phillip@squashfs.org.uk>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org,
Phillip Lougher <phillip@squashfs.org.uk>,
Chris Murphy <lists@colorremedies.com>
Subject: [PATCH] Squashfs: don't call kmalloc in decompressors
Date: Mon, 22 Aug 2022 22:54:30 +0100 [thread overview]
Message-ID: <20220822215430.15933-1-phillip@squashfs.org.uk> (raw)
The decompressors may be called while in an atomic section.
So move the kmalloc() out of this path, and into the "page actor"
init function.
This fixes a regression introduced by commit
f268eedddf35 ("squashfs: extend "page actor" to handle missing pages")
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
fs/squashfs/file.c | 2 +-
fs/squashfs/file_direct.c | 2 +-
fs/squashfs/page_actor.c | 34 +++++++++++++++-------------------
fs/squashfs/page_actor.h | 5 +++++
4 files changed, 22 insertions(+), 21 deletions(-)
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index 98e64fec75b7..e56510964b22 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -593,7 +593,7 @@ static void squashfs_readahead(struct readahead_control *ractl)
res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
- kfree(actor);
+ squashfs_page_actor_free(actor);
if (res == expected) {
int bytes;
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
index be4b12d31e0c..f1ccad519e28 100644
--- a/fs/squashfs/file_direct.c
+++ b/fs/squashfs/file_direct.c
@@ -74,7 +74,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
/* Decompress directly into the page cache buffers */
res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
- kfree(actor);
+ squashfs_page_actor_free(actor);
if (res < 0)
goto mark_errored;
diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c
index b23b780d8f42..54b93bf4a25c 100644
--- a/fs/squashfs/page_actor.c
+++ b/fs/squashfs/page_actor.c
@@ -52,6 +52,7 @@ struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
actor->buffer = buffer;
actor->pages = pages;
actor->next_page = 0;
+ actor->tmp_buffer = NULL;
actor->squashfs_first_page = cache_first_page;
actor->squashfs_next_page = cache_next_page;
actor->squashfs_finish_page = cache_finish_page;
@@ -68,20 +69,9 @@ static void *handle_next_page(struct squashfs_page_actor *actor)
if ((actor->next_page == actor->pages) ||
(actor->next_index != actor->page[actor->next_page]->index)) {
- if (actor->alloc_buffer) {
- void *tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
-
- if (tmp_buffer) {
- actor->tmp_buffer = tmp_buffer;
- actor->next_index++;
- actor->returned_pages++;
- return tmp_buffer;
- }
- }
-
actor->next_index++;
actor->returned_pages++;
- return ERR_PTR(-ENOMEM);
+ return actor->alloc_buffer ? actor->tmp_buffer : ERR_PTR(-ENOMEM);
}
actor->next_index++;
@@ -96,11 +86,10 @@ static void *direct_first_page(struct squashfs_page_actor *actor)
static void *direct_next_page(struct squashfs_page_actor *actor)
{
- if (actor->pageaddr)
+ if (actor->pageaddr) {
kunmap_local(actor->pageaddr);
-
- kfree(actor->tmp_buffer);
- actor->pageaddr = actor->tmp_buffer = NULL;
+ actor->pageaddr = NULL;
+ }
return handle_next_page(actor);
}
@@ -109,8 +98,6 @@ static void direct_finish_page(struct squashfs_page_actor *actor)
{
if (actor->pageaddr)
kunmap_local(actor->pageaddr);
-
- kfree(actor->tmp_buffer);
}
struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_info *msblk,
@@ -121,6 +108,16 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_
if (actor == NULL)
return NULL;
+ if (msblk->decompressor->alloc_buffer) {
+ actor->tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+ if (actor->tmp_buffer == NULL) {
+ kfree(actor);
+ return NULL;
+ }
+ } else
+ actor->tmp_buffer = NULL;
+
actor->length = length ? : pages * PAGE_SIZE;
actor->page = page;
actor->pages = pages;
@@ -128,7 +125,6 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_
actor->returned_pages = 0;
actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
actor->pageaddr = NULL;
- actor->tmp_buffer = NULL;
actor->alloc_buffer = msblk->decompressor->alloc_buffer;
actor->squashfs_first_page = direct_first_page;
actor->squashfs_next_page = direct_next_page;
diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h
index 24841d28bc0f..95ffbb543d91 100644
--- a/fs/squashfs/page_actor.h
+++ b/fs/squashfs/page_actor.h
@@ -29,6 +29,11 @@ extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
extern struct squashfs_page_actor *squashfs_page_actor_init_special(
struct squashfs_sb_info *msblk,
struct page **page, int pages, int length);
+static inline void squashfs_page_actor_free(struct squashfs_page_actor *actor)
+{
+ kfree(actor->tmp_buffer);
+ kfree(actor);
+}
static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
{
return actor->squashfs_first_page(actor);
--
2.35.1
reply other threads:[~2022-08-22 21:56 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220822215430.15933-1-phillip@squashfs.org.uk \
--to=phillip@squashfs.org.uk \
--cc=akpm@linux-foundation.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lists@colorremedies.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox