From: Kalesh Singh <kaleshsingh@xxxxxxxxxx> Subject: procfs/dmabuf: add inode number to /proc/*/fdinfo And 'ino' field to /proc/<pid>/fdinfo/<FD> and /proc/<pid>/task/<tid>/fdinfo/<FD>. The inode numbers can be used to uniquely identify DMA buffers in user space and avoids a dependency on /proc/<pid>/fd/* when accounting per-process DMA buffer sizes. Link: https://lkml.kernel.org/r/20210308170651.919148-2-kaleshsingh@xxxxxxxxxx Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx> Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Acked-by: Christian König <christian.koenig@xxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Jeff Vander Stoep <jeffv@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Hridya Valsaraju <hridya@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Alexey Gladkov <gladkov.alexey@xxxxxxxxx> Cc: Szabolcs Nagy <szabolcs.nagy@xxxxxxx> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> Cc: Andrei Vagin <avagin@xxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Cc: James Morris <jamorris@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/filesystems/proc.rst | 37 ++++++++++++++++++++++----- fs/proc/fd.c | 5 ++- 2 files changed, 34 insertions(+), 8 deletions(-) --- a/Documentation/filesystems/proc.rst~procfs-dmabuf-add-inode-number-to-proc-fdinfo +++ a/Documentation/filesystems/proc.rst @@ -1920,18 +1920,20 @@ if precise results are needed. 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file --------------------------------------------------------------- This file provides information associated with an opened file. The regular -files have at least three fields -- 'pos', 'flags' and 'mnt_id'. The 'pos' -represents the current offset of the opened file in decimal form [see lseek(2) -for details], 'flags' denotes the octal O_xxx mask the file has been -created with [see open(2) for details] and 'mnt_id' represents mount ID of -the file system containing the opened file [see 3.5 /proc/<pid>/mountinfo -for details]. +files have at least four fields -- 'pos', 'flags', 'mnt_id' and 'ino'. +The 'pos' represents the current offset of the opened file in decimal +form [see lseek(2) for details], 'flags' denotes the octal O_xxx mask the +file has been created with [see open(2) for details] and 'mnt_id' represents +mount ID of the file system containing the opened file [see 3.5 +/proc/<pid>/mountinfo for details]. 'ino' represents the inode number of +the file. A typical output is:: pos: 0 flags: 0100002 mnt_id: 19 + ino: 63107 All locks associated with a file descriptor are shown in its fdinfo too:: @@ -1948,6 +1950,7 @@ Eventfd files pos: 0 flags: 04002 mnt_id: 9 + ino: 63107 eventfd-count: 5a where 'eventfd-count' is hex value of a counter. @@ -1960,6 +1963,7 @@ Signalfd files pos: 0 flags: 04002 mnt_id: 9 + ino: 63107 sigmask: 0000000000000200 where 'sigmask' is hex value of the signal mask associated @@ -1973,6 +1977,7 @@ Epoll files pos: 0 flags: 02 mnt_id: 9 + ino: 63107 tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af sdev:7 where 'tfd' is a target file descriptor number in decimal form, @@ -1989,6 +1994,8 @@ For inotify files the format is the foll pos: 0 flags: 02000000 + mnt_id: 9 + ino: 63107 inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d where 'wd' is a watch descriptor in decimal form, i.e. a target file @@ -2011,6 +2018,7 @@ For fanotify files the format is:: pos: 0 flags: 02 mnt_id: 9 + ino: 63107 fanotify flags:10 event-flags:0 fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003 fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4 @@ -2035,6 +2043,7 @@ Timerfd files pos: 0 flags: 02 mnt_id: 9 + ino: 63107 clockid: 0 ticks: 0 settime flags: 01 @@ -2049,6 +2058,22 @@ details]. 'it_value' is remaining time u with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' still exhibits timer's remaining time. +DMA Buffer files +~~~~~~~~~~~~~~~~ + +:: + + pos: 0 + flags: 04002 + mnt_id: 9 + ino: 63107 + size: 32768 + count: 2 + exp_name: system-heap + +where 'size' is the size of the DMA buffer in bytes. 'count' is the file count of +the DMA buffer file. 'exp_name' is the name of the DMA buffer exporter. + 3.9 /proc/<pid>/map_files - Information about memory mapped files --------------------------------------------------------------------- This directory contains symbolic links which represent memory mapped files --- a/fs/proc/fd.c~procfs-dmabuf-add-inode-number-to-proc-fdinfo +++ a/fs/proc/fd.c @@ -54,9 +54,10 @@ static int seq_show(struct seq_file *m, if (ret) return ret; - seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n", + seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n", (long long)file->f_pos, f_flags, - real_mount(file->f_path.mnt)->mnt_id); + real_mount(file->f_path.mnt)->mnt_id, + file_inode(file)->i_ino); /* show_fd_locks() never deferences files so a stale value is safe */ show_fd_locks(m, file, files); _
