diff options
Diffstat (limited to 'Documentation/filesystems/sysfs.txt')
| -rw-r--r-- | Documentation/filesystems/sysfs.txt | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 4598ef7b622..7f27b8f840d 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -176,8 +176,10 @@ implementations: Recall that an attribute should only be exporting one value, or an array of similar values, so this shouldn't be that expensive. - This allows userspace to do partial reads and seeks arbitrarily over - the entire file at will. + This allows userspace to do partial reads and forward seeks + arbitrarily over the entire file at will. If userspace seeks back to + zero or does a pread(2) with an offset of '0' the show() method will + be called again, rearmed, to fill the buffer. - On write(2), sysfs expects the entire buffer to be passed during the first write. Sysfs then passes the entire buffer to the store() @@ -192,6 +194,9 @@ implementations: Other notes: +- Writing causes the show() method to be rearmed regardless of current + file position. + - The buffer will always be PAGE_SIZE bytes in length. On i386, this is 4096. |