The patch titled
vfs: introduce noop_llseek()
has been added to the -mm tree. Its filename is
vfs-introduce-noop_llseek.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vfs: introduce noop_llseek()
From: jan Blunck <jblunck@xxxxxxx>
This is an implementation of ->llseek useable for the rare special case
when userspace expects the seek to succeed but the (device) file is
actually not able to perform the seek. In this case you use noop_llseek()
instead of falling back to the default implementation of ->llseek.
Signed-off-by: Jan Blunck <jblunck@xxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/read_write.c | 17 +++++++++++++++++
include/linux/fs.h | 1 +
2 files changed, 18 insertions(+)
diff -puN fs/read_write.c~vfs-introduce-noop_llseek fs/read_write.c
--- a/fs/read_write.c~vfs-introduce-noop_llseek
+++ a/fs/read_write.c
@@ -97,6 +97,23 @@ loff_t generic_file_llseek(struct file *
}
EXPORT_SYMBOL(generic_file_llseek);
+/**
+ * noop_llseek - No Operation Performed llseek implementation
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @origin: type of seek
+ *
+ * This is an implementation of ->llseek useable for the rare special case when
+ * userspace expects the seek to succeed but the (device) file is actually not
+ * able to perform the seek. In this case you use noop_llseek() instead of
+ * falling back to the default implementation of ->llseek.
+ */
+loff_t noop_llseek(struct file *file, loff_t offset, int origin)
+{
+ return file->f_pos;
+}
+EXPORT_SYMBOL(noop_llseek);
+
loff_t no_llseek(struct file *file, loff_t offset, int origin)
{
return -ESPIPE;
diff -puN include/linux/fs.h~vfs-introduce-noop_llseek include/linux/fs.h
--- a/include/linux/fs.h~vfs-introduce-noop_llseek
+++ a/include/linux/fs.h
@@ -2238,6 +2238,7 @@ extern long do_splice_direct(struct file
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 origin);
extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
extern loff_t generic_file_llseek_unlocked(struct file *file, loff_t offset,
_
Patches currently in -mm which might be from jblunck@xxxxxxx are
osst-update-ppos-instead-of-using-file-f_pos.patch
drivers-sbus-char-flashc-flash_read-should-update-ppos-instead-of-file-f_pos.patch
arch-cris-arch-v10-drivers-eepromc-eeprom_read-eeprom_write-should-update-ppos-instead-of-file-f_pos.patch
frv-remove-struct-file-argument-from-sysctl-proc_handler.patch
misdn-remove-unnecessary-test-on-f_pos.patch
zcrypt-use-nonseekable_open.patch
rtc-m41t80-use-nonseekable_open.patch
vfs-introduce-noop_llseek.patch
osst-use-noop_llseek-instead-of-default_llseek.patch
st-use-noop_llseek-instead-of-default_llseek.patch
fs-do-not-fallback-to-default_llseek-when-readdir-uses-bkl.patch
documentation-filesystems-locking-update-documentation-on-llseek-wrt-bkl.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
