From: David Hildenbrand Date: Fri, 23 Apr 2021 07:45:45 +0000 (+0200) Subject: fs: update documentation of get_write_access() and friends X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=592ca09be8333bd226f50100328a905bfc377133;p=uclinux-h8%2Flinux.git fs: update documentation of get_write_access() and friends As VM_DENYWRITE does no longer exists, let's spring-clean the documentation of get_write_access() and friends. Acked-by: "Eric W. Biederman" Acked-by: Christian König Signed-off-by: David Hildenbrand --- diff --git a/include/linux/fs.h b/include/linux/fs.h index 640574294216..e0dc3e96ed72 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3055,15 +3055,20 @@ static inline void file_end_write(struct file *file) } /* + * This is used for regular files where some users -- especially the + * currently executed binary in a process, previously handled via + * VM_DENYWRITE -- cannot handle concurrent write (and maybe mmap + * read-write shared) accesses. + * * get_write_access() gets write permission for a file. * put_write_access() releases this write permission. - * This is used for regular files. - * We cannot support write (and maybe mmap read-write shared) accesses and - * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode - * can have the following values: - * 0: no writers, no VM_DENYWRITE mappings - * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist - * > 0: (i_writecount) users are writing to the file. + * deny_write_access() denies write access to a file. + * allow_write_access() re-enables write access to a file. + * + * The i_writecount field of an inode can have the following values: + * 0: no write access, no denied write access + * < 0: (-i_writecount) users that denied write access to the file. + * > 0: (i_writecount) users that have write access to the file. * * Normally we operate on that counter with atomic_{inc,dec} and it's safe * except for the cases where we don't hold i_writecount yet. Then we need to