diff options
| author | Max Kellermann <max.kellermann@ionos.com> | 2023-09-19 09:37:42 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-10-05 13:34:05 +0200 |
| commit | 1b057bd800c3ea0c926191d7950cd2365eddc9bb (patch) | |
| tree | fd2479575d90eea9432fb808cc0ed3119197f9bf /drivers/char/mem.c | |
| parent | 19e3e6cdfdc73400eb68d1102cdbad4f9493f474 (diff) | |
drivers/char/mem: implement splice() for /dev/zero, /dev/full
This allows splicing zeroed pages into a pipe, and allows discarding
pages from a pipe by splicing them to /dev/zero. Writing to /dev/zero
should have the same effect as writing to /dev/null, and a
"splice_write" implementation exists only for /dev/null.
(The /dev/zero splice_read implementation could be optimized by
pushing references to the global zero page to the pipe, but that's an
optimization for another day.)
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Link: https://lore.kernel.org/r/20230919073743.1066313-1-max.kellermann@ionos.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 1052b0f2d4cf..263c19cd6fb9 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -640,6 +640,7 @@ static int open_port(struct inode *inode, struct file *filp) #define full_lseek null_lseek #define write_zero write_null #define write_iter_zero write_iter_null +#define splice_write_zero splice_write_null #define open_mem open_port static const struct file_operations __maybe_unused mem_fops = { @@ -677,6 +678,8 @@ static const struct file_operations zero_fops = { .read_iter = read_iter_zero, .read = read_zero, .write_iter = write_iter_zero, + .splice_read = copy_splice_read, + .splice_write = splice_write_zero, .mmap = mmap_zero, .get_unmapped_area = get_unmapped_area_zero, #ifndef CONFIG_MMU @@ -688,6 +691,7 @@ static const struct file_operations full_fops = { .llseek = full_lseek, .read_iter = read_iter_zero, .write = write_full, + .splice_read = copy_splice_read, }; static const struct memdev { |