From c51acdb78f92719127995c0fe41108df0552edc3 Mon Sep 17 00:00:00 2001 From: Tal Zussman Date: Fri, 31 Dec 2021 02:57:50 -0500 Subject: fs: Remove FIXME comment in generic_write_checks() This patch removes an unnecessary comment that had to do with block special files from `generic_write_checks()`. The comment, originally added in Linux v2.4.14.9, was to clarify that we only set `pos` to the file size when the file was opened with `O_APPEND` if the file wasn't a block special file. Prior to Linux v2.4, block special files had a different `write()` function which was unified into a generic `write()` function in Linux v2.4. This generic `write()` function called `generic_write_checks()`. For more details, see this earlier conversation: https://lore.kernel.org/linux-fsdevel/Yc4Czk5A+p5p2Y4W@mit.edu/ Currently, block special devices have their own `write_iter()` function and no longer share the same `generic_write_checks()`, therefore rendering the comment irrelevant. Signed-off-by: Tal Zussman Co-authored-by: Xijiao Li Co-authored-by: Hans Montero Suggested-by: Theodore Ts'o Signed-off-by: Al Viro --- fs/read_write.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs') diff --git a/fs/read_write.c b/fs/read_write.c index 0074afa7ecb3..0173dc7183c9 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1637,7 +1637,6 @@ ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) if (!iov_iter_count(from)) return 0; - /* FIXME: this is for backwards compatibility with 2.4 */ if (iocb->ki_flags & IOCB_APPEND) iocb->ki_pos = i_size_read(inode); -- cgit v1.2.3 From 1e2d84644d1ce754d48c58a6184e1dd9ab573f0c Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 18 Jun 2021 20:27:57 -0400 Subject: constify struct path argument of finish_automount()/do_add_mount() Signed-off-by: Al Viro --- fs/internal.h | 2 +- fs/namespace.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/internal.h b/fs/internal.h index 8590c973c2f4..fe0a44c4ab88 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -74,7 +74,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd, * namespace.c */ extern struct vfsmount *lookup_mnt(const struct path *); -extern int finish_automount(struct vfsmount *, struct path *); +extern int finish_automount(struct vfsmount *, const struct path *); extern int sb_prepare_remount_readonly(struct super_block *); diff --git a/fs/namespace.c b/fs/namespace.c index 40b994a29e90..13d025a9ecf5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2876,7 +2876,7 @@ static int do_move_mount_old(struct path *path, const char *old_name) * add a mount into a namespace's mount tree */ static int do_add_mount(struct mount *newmnt, struct mountpoint *mp, - struct path *path, int mnt_flags) + const struct path *path, int mnt_flags) { struct mount *parent = real_mount(path->mnt); @@ -2999,7 +2999,7 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags, return err; } -int finish_automount(struct vfsmount *m, struct path *path) +int finish_automount(struct vfsmount *m, const struct path *path) { struct dentry *dentry = path->dentry; struct mountpoint *mp; -- cgit v1.2.3 From 90b2433edb6d995bd23d6adde753095b4ab26104 Mon Sep 17 00:00:00 2001 From: Maíra Canal Date: Mon, 31 Jan 2022 15:22:42 -0300 Subject: seq_file: fix NULL pointer arithmetic warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Implement conditional logic in order to replace NULL pointer arithmetic. The use of NULL pointer arithmetic was pointed out by clang with the following warning: fs/kernfs/file.c:128:15: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return NULL + !*ppos; ~~~~ ^ fs/seq_file.c:559:14: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return NULL + (*pos == 0); Signed-off-by: Maíra Canal Signed-off-by: Al Viro --- fs/kernfs/file.c | 7 +------ fs/seq_file.c | 4 ++-- include/linux/seq_file.h | 1 + 3 files changed, 4 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 9414a7a60a9f..7aefaca876a0 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -120,13 +120,8 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) if (next == ERR_PTR(-ENODEV)) kernfs_seq_stop_active(sf, next); return next; - } else { - /* - * The same behavior and code as single_open(). Returns - * !NULL if pos is at the beginning; otherwise, NULL. - */ - return NULL + !*ppos; } + return single_start(sf, ppos); } static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) diff --git a/fs/seq_file.c b/fs/seq_file.c index f8e1f4ee87ff..7ab8a58c29b6 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -554,9 +554,9 @@ int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc) } EXPORT_SYMBOL(seq_dentry); -static void *single_start(struct seq_file *p, loff_t *pos) +void *single_start(struct seq_file *p, loff_t *pos) { - return NULL + (*pos == 0); + return *pos ? NULL : SEQ_START_TOKEN; } static void *single_next(struct seq_file *p, void *v, loff_t *pos) diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 88cc16444b43..60820ab511d2 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -162,6 +162,7 @@ int seq_dentry(struct seq_file *, struct dentry *, const char *); int seq_path_root(struct seq_file *m, const struct path *path, const struct path *root, const char *esc); +void *single_start(struct seq_file *, loff_t *); int single_open(struct file *, int (*)(struct seq_file *, void *), void *); int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t); int single_release(struct inode *, struct file *); -- cgit v1.2.3 From 124f75f864f38327e3e7e182e6b6da5105e2bade Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 13 Feb 2022 22:42:30 -0500 Subject: clean overflow checks in count_mounts() a bit Wraparound checks in there are redundant (x + y < x and x + y < y are equivalent when x and y are both unsigned int). IMO more straightforward code would be better here... Signed-off-by: Al Viro --- fs/namespace.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) (limited to 'fs') diff --git a/fs/namespace.c b/fs/namespace.c index 13d025a9ecf5..42d4fc21263b 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2069,22 +2069,23 @@ static int invent_group_ids(struct mount *mnt, bool recurse) int count_mounts(struct mnt_namespace *ns, struct mount *mnt) { unsigned int max = READ_ONCE(sysctl_mount_max); - unsigned int mounts = 0, old, pending, sum; + unsigned int mounts = 0; struct mount *p; + if (ns->mounts >= max) + return -ENOSPC; + max -= ns->mounts; + if (ns->pending_mounts >= max) + return -ENOSPC; + max -= ns->pending_mounts; + for (p = mnt; p; p = next_mnt(p, mnt)) mounts++; - old = ns->mounts; - pending = ns->pending_mounts; - sum = old + pending; - if ((old > sum) || - (pending > sum) || - (max < sum) || - (mounts > (max - sum))) + if (mounts > max) return -ENOSPC; - ns->pending_mounts = pending + mounts; + ns->pending_mounts += mounts; return 0; } -- cgit v1.2.3 From 61e02cdb6ac68a84f1bb95026632d63677f26202 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Mon, 14 Mar 2022 16:46:05 +0100 Subject: aio: drop needless assignment in aio_read() Commit 84c4e1f89fef ("aio: simplify - and fix - fget/fput for io_submit()") refactored aio_read() and some error cases into early return, which made some intermediate assignment of the return variable needless. Drop this needless assignment in aio_read(). No functional change. No change in resulting object code. Signed-off-by: Lukas Bulwahn Signed-off-by: Al Viro --- fs/aio.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs') diff --git a/fs/aio.c b/fs/aio.c index 4ceba13a7db0..3b7cdcc2a02e 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1553,7 +1553,6 @@ static int aio_read(struct kiocb *req, const struct iocb *iocb, file = req->ki_filp; if (unlikely(!(file->f_mode & FMODE_READ))) return -EBADF; - ret = -EINVAL; if (unlikely(!file->f_op->read_iter)) return -EINVAL; -- cgit v1.2.3