From: "Jason A. Donenfeld" Jason@zx2c4.com

Pipe-like behaviour on llseek(2) (i.e. unconditionally failing with -ESPIPE) can be expresses in 3 ways: 1) ->llseek set to NULL in file_operations 2) ->llseek set to no_llseek in file_operations 3) FMODE_LSEEK *not* set in ->f_mode.

Enforce (3) in cases (1) and (2); that will allow to simplify the checks and eventually get rid of no_llseek boilerplate.

Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk (cherry picked from commit e7478158e1378325907edfdd960eca98a1be405b) Conflicts: fs/open.c Cc: stable@vger.kernel.org Signed-off-by: Saeed Mirzamohammadi saeed.mirzamohammadi@oracle.com --- fs/file_table.c | 2 ++ fs/open.c | 4 ++++ 2 files changed, 6 insertions(+)

diff --git a/fs/file_table.c b/fs/file_table.c index e8c9016703ad..f675817be4ad 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -198,6 +198,8 @@ static struct file *alloc_file(const struct path *path, int flags, file->f_mapping = path->dentry->d_inode->i_mapping; file->f_wb_err = filemap_sample_wb_err(file->f_mapping); file->f_sb_err = file_sample_sb_err(file); + if (fop->llseek && fop->llseek != no_llseek) + file->f_mode |= FMODE_LSEEK; if ((file->f_mode & FMODE_READ) && likely(fop->read || fop->read_iter)) file->f_mode |= FMODE_CAN_READ; diff --git a/fs/open.c b/fs/open.c index 1ba1d2ab2ef0..38bf38d41418 100644 --- a/fs/open.c +++ b/fs/open.c @@ -834,6 +834,10 @@ static int do_dentry_open(struct file *f, if ((f->f_mode & FMODE_WRITE) && likely(f->f_op->write || f->f_op->write_iter)) f->f_mode |= FMODE_CAN_WRITE; + if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek) + f->f_mode &= ~FMODE_LSEEK; + if ((f->f_mode & FMODE_LSEEK) && f->f_op->llseek == no_llseek) + f->f_mode &= ~FMODE_LSEEK;

f->f_write_hint = WRITE_LIFE_NOT_SET; f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);

From: "Jason A. Donenfeld" Jason@zx2c4.com

This is already set by anon_inode_getfile(), since dma_buf_fops has non-NULL ->llseek, so we don't need to set it here too.

Acked-by: Daniel Vetter daniel.vetter@ffwll.ch Acked-by: Sumit Semwal sumit.semwal@linaro.org Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk (cherry picked from commit c9eb2d427c1c428e4f4e29f1e635b9a83236c015) Cc: stable@vger.kernel.org Signed-off-by: Saeed Mirzamohammadi saeed.mirzamohammadi@oracle.com --- drivers/dma-buf/dma-buf.c | 1 - 1 file changed, 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 968c3df2810e..3c3d0e2258b4 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -584,7 +584,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) goto err_dmabuf; }

- file->f_mode |= FMODE_LSEEK; dmabuf->file = file;

mutex_init(&dmabuf->lock);

From: "Jason A. Donenfeld" Jason@zx2c4.com

Now that all callers of ->llseek are going through vfs_llseek(), we don't gain anything by keeping no_llseek around. Nothing actually calls it and setting ->llseek to no_lseek is completely equivalent to leaving it NULL.

Longer term (== by the end of merge window) we want to remove all such intializations. To simplify the merge window this commit does *not* touch initializers - it only defines no_llseek as NULL (and simplifies the tests on file opening).

At -rc1 we'll need do a mechanical removal of no_llseek -

git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/<no_llseek>/d' $i done would do it.

Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk (cherry picked from commit 868941b14441282ba08761b770fc6cad69d5bdb7) Conflicts: fs/open.c Cc: stable@vger.kernel.org Signed-off-by: Saeed Mirzamohammadi saeed.mirzamohammadi@oracle.com --- Documentation/filesystems/porting.rst | 8 ++++++++ drivers/gpu/drm/drm_file.c | 3 +-- fs/file_table.c | 2 +- fs/read_write.c | 6 ------ include/linux/fs.h | 2 +- kernel/bpf/bpf_iter.c | 3 +-- 6 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index bf19fd6b86e7..9d362f80a644 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -908,3 +908,11 @@ Calling conventions for file_open_root() changed; now it takes struct path * instead of passing mount and dentry separately. For callers that used to pass <mnt, mnt->mnt_root> pair (i.e. the root of given mount), a new helper is provided - file_open_root_mnt(). In-tree users adjusted. + +--- + +**mandatory** + +no_llseek is gone; don't set .llseek to that - just leave it NULL instead. +Checks for "does that file have llseek(2), or should it fail with ESPIPE" +should be done by looking at FMODE_LSEEK in file->f_mode. diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index ed25168619fc..dc7d2e5b16c8 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -552,8 +552,7 @@ EXPORT_SYMBOL(drm_release_noglobal); * Since events are used by the KMS API for vblank and page flip completion this * means all modern display drivers must use it. * - * @offset is ignored, DRM events are read like a pipe. Therefore drivers also - * must set the &file_operation.llseek to no_llseek(). Polling support is + * @offset is ignored, DRM events are read like a pipe. Polling support is * provided by drm_poll(). * * This function will only ever read a full event. Therefore userspace must diff --git a/fs/file_table.c b/fs/file_table.c index f675817be4ad..652b70841df6 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -198,7 +198,7 @@ static struct file *alloc_file(const struct path *path, int flags, file->f_mapping = path->dentry->d_inode->i_mapping; file->f_wb_err = filemap_sample_wb_err(file->f_mapping); file->f_sb_err = file_sample_sb_err(file); - if (fop->llseek && fop->llseek != no_llseek) + if (fop->llseek) file->f_mode |= FMODE_LSEEK; if ((file->f_mode & FMODE_READ) && likely(fop->read || fop->read_iter)) diff --git a/fs/read_write.c b/fs/read_write.c index b64527211b32..582beb67e48e 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -227,12 +227,6 @@ loff_t noop_llseek(struct file *file, loff_t offset, int whence) } EXPORT_SYMBOL(noop_llseek);

-loff_t no_llseek(struct file *file, loff_t offset, int whence) -{ - return -ESPIPE; -} -EXPORT_SYMBOL(no_llseek); - loff_t default_llseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file_inode(file); diff --git a/include/linux/fs.h b/include/linux/fs.h index 76162f046670..f5eac9d76e9d 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3174,7 +3174,7 @@ extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, extern void file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping); extern loff_t noop_llseek(struct file *file, loff_t offset, int whence); -extern loff_t no_llseek(struct file *file, loff_t offset, int whence); +#define no_llseek NULL extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize); extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence); extern loff_t generic_file_llseek_size(struct file *file, loff_t offset, diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index b2ee45064e06..60e8f611954e 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -80,10 +80,9 @@ static bool bpf_iter_support_resched(struct seq_file *seq) #define MAX_ITER_OBJECTS 1000000

/* bpf_seq_read, a customized and simpler version for bpf iterator. - * no_llseek is assumed for this file. * The following are differences from seq_read(): * . fixed buffer size (PAGE_SIZE) - * . assuming no_llseek + * . assuming NULL ->llseek() * . stop() may call bpf program, handling potential overflow there */ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,